Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world.
Compiled 14 September
A more indicative measure of ENSO
ENSO stands for ElNinoSouthernOsciallation
The EN part of this parameter deals with sea temperature. We have been using the sea surface temperature measured in the Nino3-4 area as the parameter for deciding if the atmosphere is being driven by El Nino or La Nino or is in between the two in neutral gear. The SO part deals with the isobaric pressure difference between Darwin and Tahiti… located on this map:

However, climate change has been raising the world's average sea temperate in a roller-coaster fashion

Too try and remove this trend from the measurements, BoM have introduced a new measure called the RELATIVE NINO INDICIES.
As seen on their web site https://www.bom.gov.au/climate/enso/
Relative Niño indices
Traditional Niño index values were used at the Bureau of Meteorology until September 2025. From September 2025, the Bureau uses Relative Niño indices, which measure sea surface temperature anomalies in the tropical Pacific Ocean in the Niño regions, but calculated relative to the global tropical region temperature anomaly. This is to relate the indices more closely to the localised processes associated with ENSO, rather than larger-scale tropical SST features such as global warming.
Example: The Relative Niño3.4 index calculation:
Relative Niño3.4 = S x [(Niño3.4obs – Niño3.4clim) – (Tropical Meanobs – Tropical Meanclim)]
Where Niño3.4obs and Tropical Meanobs are the SST averages over the Niño3.4 region and the 20°S to 20°N tropical mean SST, respectively, while Niño3.4clim and Tropical Meanclim are the climatological values for the appropriate day/month depending on the dataset. S is a scaling factor applied so the variance of the relative Niño index matches that of the traditional index.
Sustained monthly Relative Niño3 or Niño3.4 index values above +0.8 °C as typical of El Niño conditions, with values of below −0.8 °C as typical of La Niña. These values are approximately one standard deviation from the long-term mean (e.g., around 70% of all monthly Niño3.4 values, lie between −0.8 °C and +0.8 °C).

This is what REL NINO 3-4 looks like going back to April 2021

It gives a good view of the El Nino in late 23/early 24
and the La Nina of late24/early 25 and shows a neutral trend in recent data.

BoM reports that there is now a negative IOD event and it is expected to continue during spring, until at least the next month. This is likely to bring wet conditions to parts of southern and eastern Australia.

TROPICS
The latest cyclone activity report is at zoom.earth and tropic.ssec.wisc.edu and Tropical Cyclone Potential is from https://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

•A tornado spawned by Tropical Storm Peipah southwest of Tokyo tore roofs off homes and flipped cars.
• China's Guangdong province was drenched by Typhoon Tapah
• Hurricane Kiko weakened to a tropical storm just before skirting the northern Hawaiian Islands.
• MARIO is moving out to sea off south of Baja California.

Weather Zones
Mid-week GFS model showing isobars, winds, waves (purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge), SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Rain accumulation this week from Windy.com below shows well defined SPCZ between Solomon Islands and Funafuti and again east of Samoa. The eastern branch is forecast to shift south and form a depression L1 near the Southern Cooks late in the week.
Intense rain is forecast for Southern Alps in New Zealand especially with trough 2 on Tuesday and Wednesday.

Wind accumulation from windy.com below shows a windy area from Samoa to Southern Cooks late in the week with development of L1 from off the SPC. The disturbed westerlies south of 35S are typical of spring.

LOWS and HIGHS
There is a steady easterly migration with trough 1 followed by H1, then trough 2 and High2 then trough 3.

Trough 2 is expected over NZ on Tuesday and Wednesday preceded by NW winds, accompanied by rain heavy over the mountains and followed by a day or so of chilly SW winds. Then H2 crosses north island on Friday and Saturday. The sequence then repeats next week.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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Bob Blog

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world.
Compiled 07 September
Blood moon tonight
We are having a full moon locally Monday morning (6am in Auckland). And lunar perigee (closest earth-moon distance for the month) is on Wednesday. The moon is passing thru the earth's shadow tonight= a lunar eclipse. And since we are near perigee the moon is larger than normal so will receive some light that has gone thru the earth's atmosphere when in the outer or penumbral ring of the earth's shadow. This light is a brownish red (the blue part of its spectrum has been scattered away). Hence we are having A BLOOD MOON.

Timing in UTC on 7 September 2025
P1 Penumbral begins 1528UTC
U1 Partial begins 1627UTC
U2 Total begins 1730UTC
GE Greatest eclipse 1811UTC
U3 Total ends 1852UTC
U4 Partial ends 1956UTC
P4 Penumbral ends 2055 UTC
Moonset in Auckland is at 6:37am/ 1837UTC and in Sydney at 6:11am/2011UTC
So the kiwi may see a brief reddish glow on the setting moon, and the kangaroo gets to see most of the eclipse --- if the clouds don't get in the way.

A fortnight later we get the corresponding solar eclipse (moon shadow) which will be visible in New Zealand.
The sun will rise already partially eclipsed on Mon 22 Sep. In Auckland about 60% of the sun's disk will be covered. in Stewart Island as much as 75%
And this solar eclipse occurs one day before the vernal equinox.




TROPICS


. Minimal Tropical Storm Nongfa drenched parts of Vietnam that were already left soggy by Typhoon Kajiki a week before.
. Hurricane Kiko intensified to Category-3 force midway between Baja California and Hawaii and is expected to take a path north of Hawaii.
. Hurricane Lorena raked Baja California


Weather Zones

 Rain accumulation this week from Windy.com shows well defined SPCZ between Solomon Islands and Funafuti. There is a passing trough early this week between Tonga and Niue weakening late in the week over Southern Cooks and another over southern French Polynesia.

Wind accumulation from windy.com shows a windy area south of French Polynesia, and another over Coral Sea and west of Vanuatu. There are some gale wind zones southwest of NZ on the backside of L2 and also on the backside of L1.
Equinoctial gales.

LOWS and HIGHS
LOW L1 crossed NZ on Saturday and is expected to travel steadily to the east. Associated trough in the tropics expected to spread from Tonga to Niue next few days then fade over Southern Cooks. It is followed by a burst of rough SW swell.
HIGH H1 is expected to travel east and drift south to 35S.
Low L2 should travel quickly along 50S crossing NZ mid-week.
HIGH H2 is expected to travel east to northeast between 35S and 25S following the trough of L1.
Low L3 is expected to deepen into a storm over Vic/NSW on Wednesday and then weaken as it crosses the Tasman Sea May reach North Island on Friday, followed by a strong southwest flow.
H3 is expected to follow L3 across Vic/NSW by the weekend then travel NE across the Tasman Sea.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the
patterned world.
Compiled 31 August 2025
A review of last month's weather
Here is a link to a YouTube clip giving an animated loop of the isobars and
streamlines in the South Pacific for the last month
www.youtube.com/watch?v=DQheG_B2I24
Lows crossed NZ on1,8,17 and 27 August, with healthy Highs in-between ..
The Low on 27 August was especially squally and thundery:

A back trajectory analysis shows that the air then arriving over NZ was a
clash between air from the north and air from the south:

The 500hPa heights and anomalies shows three healthy HIGHS crossing NZ in
August.
From http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.shtml

Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml


North Pacific just continues to war. North Atlantic has cooled. And there
seems to be some strong cooling along the southern polar circle.
There is now a NEGATIVE IOD (Indian Ocean Dipole) (west cool/east warm).
this may bring some rain to central/southern AUSTRALIA.
Also, the SAM/AAO index has gone negative over last few days , consistent
with a burst of polar air onto NZ. However, this is NOT expected to last
long.


The monthly pressure pattern and anomalies are
from http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html

During August the Subtropical ridge in both hemispheres weakened in
intensity. However, it resumed over the Tasman Sea after lower-than-normal
isobars there in July.
The monsoon is moving steadily east across Asia.

Pressure anomalies for past month
Shows a major zone of Higher isobars over NZ and lower isobars east of NZ.
with strong cold SW winds in-between.

And a zoom in on the SW Pacific
There is a new 1020 isobar over Australia and NZ , but the 1025 isobar has
faded away.
The 1015 isobar is drifting NORTH over north Australia.

TROPICS
. At least three people perished as Typhoon Kajiki battered northern and
central Vietnam with fierce winds and torrential rainfall that collapsed
homes, felled trees and turned streets in the capital of Hanoi into rivers.
. Tropical Storm Fernand formed over the North Atlantic, while Juliette
passed well off Baja California.

WEATHER ZONES
Rain accumulation this week from Windy.com below shows well defined SPCZ
between Solomon Islands and Tulavu (north of Samoa).Also a convergence zone
around the Niue area.

Wind accumulation from windy.com below shows squash zones in the tropics one
to north of Fiji and one from Tonga to the Southern Cooks. These are
associated with the passage of HIGH H1 from 35 to 30S after Wednesday.

LOWS and HIGHS
LOW L1 crossed central NZ today and is travelling quickly off to the
southeast.

HIGH H1 is expected to cross the Tasman Sea on Monday and Tuesday and NZ on
Wednesday, then travel from 35S to 30S when east of NZ. This should produce
squash zones of enhanced Se winds further north. between Tonga and Southern
Cooks late in the week. Be aware.
A Low L2 should travel quickly along 50S mid-week.
Another Low L3 is expected to form west pf H1 and then the trough of L3
should cross NZ on Friday, followed by High H2 coming from central
Australia.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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(subscribe/unsubscribe at bottom).
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>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.

Compiled 24 August 2025

NASA Extends PREFIRE Mission to 2026

NASA's PREFIRE (Polar Radiant Energy in the Far-InfraRed Experiment)
mission uses two CubeSats spectrophotometers, each no larger than a

The satellites are in what's called an asynchronous near-polar orbit,
traveling near the poles with each pass but hours apart from one
another. This provides two snapshots of the same area over time,
enabling the mission to capture phenomena that occur on short
timescales, such as cloud cover's temporary effects on the temperature
of the area beneath it.

While the tropics take in the greatest share of the Sun's energy,
winds, storms, and ocean currents carry much of that heat toward the
colder polar regions, which receive far less sunlight. Ice, snow, and
clouds in these regions then release some of the heat into space,
primarily as far-infrared radiation. The difference between the heat
absorbed in the tropics and the heat radiated out at the poles
strongly influences global temperatures and helps drive Earth's
climate and weather systems.

The global energy budget is interesting….

Note there is incoming of 341.3 W/m2 and outgoing of
101.9+238.5W/m2=340.4 .

The data collected gives new details about the changing glow found in
processes such as the melting and freezing of surface ice, seasonal
snow changes, and variations in cloud cover.

"The PREFIRE satellites show that at these longer wavelengths, the
amount of radiation going into space can differ from one type of ice
to another by as much as 5%," said Brian Drouin, PREFIRE's project
scientist at JPL. "Measurements that look at the same areas but with
shorter wavelengths do not show this difference."

"We have the capacity to collect data for the whole world, not just
the poles. What we'll be able to do is look at the size of ice
particles in clouds that affect energy exchange between Earth and
space," said PREFIRE's principal investigator, Tristan L'Ecuyer of the
University of Wisconsin–Madison. "We'll be able to incorporate the
data into weather prediction models to improve forecasts and improve
our understanding of how moisture circulates, which affects where
storms form and how precipitation moves around the world."

TROPICS

The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is
from www.ospo.noaa.gov/products/ocean/tropical/tcfp/

• Hurricane ERIN underwent one of the most rapid intensifications of
any Atlantic basin storm in history, exploding in force from a
tropical storm to a Category5 hurricane in just 25 hours.

• Tropical Storm Lingling drenched southern Japan's Kyushu Island and
nearby smaller islands.

WEATHER ZONES

Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge),
SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Rain accumulation this week from Windy.com below shows well defined
SPCZ between Solomon Islands and Fiji and a passing trough south of
Fiji and another south of French Polynesia.   Also, a large dry zone
over Australia.

Wind accumulation from windy.com below shows generally OK ailing winds
in the tropics. And the roaring forties extending  north almost to
Noumea at times .

LOWS and HIGHS

HIGH H1 centred east of NZ tonight is now moving off to the east or
northeast leaving a ridge over central NZ and a squash zone of East to
NE winds between Northland and New Caledonia.

Low L1 is tonight between Lord Howe and Noumea, and by Wednesday is
expected to be north of Northland with Front crossing Fiji.  Front
reaching Tonga area on Thursday.  Avoid.

Later in the week it should travel off to the southeast of NZ,
followed by a westerly flow.

Then L2 from the Aussie Bight is expected to cross Tasmania by Friday
and NZ on Friday /Saturday

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.com
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 17 August 2025
Are the Oceans now struggling to store extra earth heating?

See climatereanalyzer.org/clim/sst_daily/
Since July 2023 it is as if the global averaged sea temperature has
jumped into a new regime. We still cannot tell if this is a
fundamental change that may adversely energise further weather events.
In the first half of August the rise in daily global has been
extremely rapid.
Until now, 90 per cent of the excess heat created by greenhouse gas
emissions has been drawn down into the ocean. Under this new regime it
seems that this capacity for heat absorption is being lost. SO where
will the extra heat now get stored?

The Cape Reinga region over Far North New Zealand is having a winter
heatwave. However, Hauraki Gulf is just slightly above normal
See www.moanaproject.org/marine-heatwave-forecast
The rain accumulation for year to date shows that it has been wetter
than normal in northern NZ --- with the "wetter" kicking in around 21
April, and % excess much more in Auckland than around Kerikeri.
See Visual crossing data

TROPICS
. Southern Taiwan was lashed by Category-2 Typhoon Podul, which
weakened over the island before striking China's Fujian and Guangdong
provinces.
. Mexico's central Pacific coast was brushed by passing Tropical Storm
Ivo.
. Tropical Storm Awo formed briefly near Seychelles.
. Hurricane Erin is strengthening to Category-3 force north of Puerto
Rico.


WEATHER ZONES
Rain accumulation this week from Windy.com below shows well defined
SPCZ between Solomon Islands and Samo/Niue and a passing trough over
French Polynesia. Also, an area of rain along eastern seaboard of
Australia in onshore winds.

Wind accumulation from windy.com below shows a burst of strong
southerly winds over NZ in the wake of L1. Also, generally OK ailing
winds in the tropics.

LOWS and HIGHS
Low L1 is moving off to the east of New Zealand.
H1 starts off in Australian Bight and travel east along 45S across
South Tasman Sea mid-week and onto NZ next weekend.
L2 is expected to follow H1
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 10 Aug

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 10 August 2025
TROPICS
The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
http://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

Tropical storm development across the Northern Hemisphere increased,
with Typhoon Krosa and Tropical Storm Bailu churning the western
Pacific.
. Hurricane Gil formed off Mexico, while Tropical Storm Henriette
passed northeast of Hawaii.
. Tropical Storm Dexter spun up over the Atlantic.
WEATHER ZONES
Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge),
SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Rain accumulation this week from Windy.com shows well defined SPCZ
between Solomon Islands and Tuvalu. Also, heavy rain along 25S from
175E to Rarotonga (avoid).

Wind accumulation from windy.com shows zones of strong wind around L1.
There are also bursts of wind expected south of New Caledonia and off
Sydney later in the week. (avoid).

LOWS and HIGHS
Low L1 is deepening near New Caledonia tonight and expected to travel
slowly to East-southeast reaching 29S 175W by mid-week.
Another Low is expected to form between New Caledonia and Norfolk by
Friday and trave to Tonga 16/17 August (avoid).
HIGH H1 is expected to travel steadily east along 35 to 40S, starting
this week west of Perth, reaching Adelaide by Mid-week and crossing NZ
on Friday 15 Aug.
By then there may be a squash zone of strong easterly winds around 30S
between the High over NZ and the new Low then near Fiji. Avoid.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
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(subscribe/unsubscribe at bottom).
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>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 3 Aug 2025

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 3 August 2025

A review of last month's weather

Here is a link to a YouTube clip giving an animated loop of the
isobars and streamlines in the South Pacific for the last month
youtu.be/gjWlhQmSeTs

Lows crossed NZ on 4-5, 11, 17 and 29-31 July …. Almost continuing a
weekly cycle, but also a blocking HIGH between 20 and 29 July.

The Low on 29-31 brought heavy rain to Tasman/Nelson/Marlborough area
and Bay of Plenty area.

The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern,

From http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.
shtml

Sea Surface temperature anomalies
 from psl.noaa.gov/map/clim/sst.shtml

The build-up of heat east of Japan an in the north Atlantic is
continuing.

The cooling /upwelling off Peru has finished.

The Sothern Annual Mode /AAO spent first half of July positive,
accentuating the polar vortex.

The monthly pressure pattern and anomalies are

from http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html

During July the roaring 40s in the southern hemisphere moved north.
The Subtropical ridge across the south Indian ocean intensified.

Pressure anomalies for past month Shows the pressure rise in south
Indian ocean to be part of a roller coast with lows over Australia and
larger Highs SE of NZ.   Deeper lows over Asia.

The 1015 isobar has shifted north to cover the south half of Tasman
Sea.
A 1025 Isobar has formed in the Indian Ocean.

TROPICS

The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is
from http://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

After lashing the far northern Philippines as a Category-1 cyclone,
Tropical Storm Co-May drenched Okinawa before bringing heavy rain and
gales to the Chinese coast around Shanghai.

 • Typhoon Krosa skirted the Japanese coast near Tokyo as a tropical
storm.

• Hurricane Iona and Tropical Storm Keli churned the open Pacific
Ocean, well to the south of Hawaii.

WEATHER ZONES

Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge),
SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Rain accumulation this week from Windy.com shows well defined SPCZ
between Solomon Islands and Tuvalu.  Also, a frontal zone from Tonga
to Austral Islands (avoid).

Wind accumulation from windy.com shows zones of strong wind around L1
and L2 and a frontal zone along 20S (avoid).

LOWS and HIGHS

Low L1 near 40S 160E, well south of Tahiti is moving off to the
southeast but leaving behind lots of southerly swell getting as far as
20S.

HIGH H1 has been travelling across New Zealand last few days and
should continue a steady eastward migration along 45S

Low 2 is the one that affected the third rugby test Wallabies beating
the British and Irish Lions in Stadium Australia, Sydney … a game
delayed by lightning and influenced by rain.  This Low is being
steered east along 28S… an uncommon path for a low. So, there is a
squash zone between it and H1 with strong easterly winds and large
swells at 30S. Avoid. 

Further west over Australia several troughs should travel southeast
across Tasmania and the South Tasman Sea reaching southern NZ by end
of the week and a large High H2 moves into the Aussie Bight and then
follows those troughs.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.

Compiled 27 July 2025

The three limbs of climate change- extreme heat, extreme drought and
flash flooding have led to increasing food prices around the world.

The Barcelona Supercomputer centre BSC has produced the following map
of these food price spikes.
See
https://www.bsc.es/news/bsc-news/countries-across-the-world-see-food-p
rice-shocks-climate-extremes-research-involving-bsc-shows

TROPICS
TC WIPHA affected northern Philippine floods, killing at least three
people. Then it lashed Hong Kong and China's Guangdong province. It
then unleashed severe flooding across the northern half of Vietnam. .
Tropical storm Francisco formed near Japan's southernmost islands,
while Typhoon Co-May raked the northern Philippine, and TC KROSA
formed further east.

WEATHER ZONES
Rain accumulation above shows well defined SPCZ between Solomon
Islands and Tuvalu/Tokelau/Samoa with another arm of convergence from
Fiji to Tonga to Southern Cooks where it has peak intensity.
Also, dry zones in Coral Sea and over eastern South Island.

The wind accumulation shows gales with L3 near Lord Howe Island, a
possible mini-squash zone between Lau /Tonga /Niue and windy squalls
over Southern Cooks.
Also, a zone of light winds around Vanuatu and SE of South Island.

LOWS and HIGHS

HIGH H1 has brought a week of wintry frosty weather /light winds to NZ
and is now moving off to the east /southeast. It is pushing a large
Low L1 on its eastern side off to the southeast. There are some
min-squash zones on its northern side.

LOW2 has been blocked by HI1and its associated frontal zone has been
lingering in the Tasman Sea. L2 should travel of to the south and the
associated frontal zone is expected to cross Noumea on Monday, Fiji to
New Zealand on Tuesday and Wednesday, then Tonga on Thursday - maybe
with a small supporting Low. Then fade as it moves further east.
Avoid.

HIGH H2 is expected to travel east along 20S - this is almost as far
north as these Highs get. It should move across the Coral Sea /Noumea
area mid-week then fade.

LOW L3 has an interesting expected-track. Coming from a low that
deepens south of Albany on Monday, it is expected to get steered
across central Australia as a weakening feature on Tuesday and
Wednesday, then to deepen rapidly whilst crossing Tasman Sea on
Thursday and reach another peak in intensity below 990hPa when
crossing Northland on Friday. Avoid.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
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Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 20K=July 2025

Bob McDavitt's ideas for sailing around the South Pacific. 20 July
2025
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.

Calving Icebergs

Authorities in Innaarsuit, a tiny village in northwestern Greenland,
warned residents to be cautious as a pair of massive icebergs loomed
just offshore. There were fears that the massive chunks of ice could
create large waves that could sweep ashore. Government photos show
towering wedges of ice overshadowing homes and businesses in the
village, which has fewer than 200 people and relies heavily on
fishing.

https://www.bbc.com/news/world-europe-44831663

TROPICS

The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is
from http://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

Tropical Storm Nari skirted the coast of Japan's Honshu Island before
becoming the first such storm to make landfall on Hokkaido since 2016

EATHER ZONES

Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge),
SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Rain accumulation this week from Windy.com

Rain accumulation above shows well defined SPCZ between Solomon
Islands and northern Vanuatu, and convergence zones between Samoa and
Southern cooks. 

Also  dry zones over NW Australia , in Coral sea and over NZ.

Wind and rain accumulation this week from Windy.com

The wind accumulation shows a squash zone along 30S between 180 and
160E.

Also, a zone of light winds over New Zealand. NO

LOWS and HIGHS

FINALLY, and for the first time this winter, we have a winter HIGH
over New Zealand this week.  Light winds, often clear skies… good for
overnight frosts and valley fogs.

Low L1 near Norfolk on Monday is travelling east along 29S and taking
a trough/Convergence zone eastwards across Vanuatu on Monday then
Fiji/Tonga on local Wednesday then  Niue on local Wednesday and
Southern cooks on local Thursday 35S and 145W (to southeast of French
Polynesia) is travelling southeast and associated trough is expected
to pass by Tahiti late this week, bringing small squalls and then a
lull.

HIGH H1 crossing New Zealand is expected to develop a squash zone of
strong easterly winds on its northern side along 30S between 180 and
160E for a time.

Trough T1 crossing the Tasman Sea following H1 this week may stall
near 160E and fade.

HIGH H2 is expected to cross central Australia this week and fade over
northern Tasman Sea this weekend as a developing Low from Australian
Bight moves into South Tasman Sea by early next week.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world.

Today, 13 July is "Seafarers Sunday". On this day several churches pray special prayers for mariners and those who livelihood involves working on the ocean. This often-dangerous job, at mercy of winds and waves, requires spending weeks away from loved ones.

Over the centuries, seafarers have worked out rules to help avoiding sailing into the right parts of passing storms. Storms are often related to passing depressions or low-pressure systems as seen on a weather map. One of these rules is the "law of storms" as compiled in the mid-19th century (see metbob.wordpress.com/2025/06/16/bob-blog-15-june/)

Basically, this can be summarised that the way to go, to evade the roughest weather is to the right of the incoming wind.
Buys-Ballot law was compiled at much the same time. In the Southern hemisphere it can be stated thus: If you look into the wind then the LOW is on the left. This means concurs with the "law of storms" to go right or put wind on port in order to evade the worst of the storm.

However, when your voyage involves encountering a passing trough then the best thing to do is to put the incoming wind on starboard and sail directly into the approaching rain. By so doing we MINIMISE the time spent in the peak conditions of the trough. This is a case where the way to go is on a starboard tack, the opposite to the law of storms. My illustrated edition today at metbob.wordpress.com/2025/07/14/bob-blog-13-july/ gives more details of this exception.


TROPICS

* Typhoon Danas in Taiwan killed two people, and more than 300 were injured.
* Two deaths are being blamed on the flooding unleashed over the Carolinas by Tropical storm Chantal.
* TC NARI is affecting east coast of Japan.

WEATHER ZONES
Rain accumulation this week from Windy.com shows well defined SPCZ between Solomon Islands and Samoa. Also a passing trough southeast of French Polynesia .

The wind accumulation shows NO squash zones in the tropics, but the westerly winds of the "roaring 40s" are extending north of 30S around the south Pacific.
LOWS and HIGHS
Low L1 near 35S and 145W (to southeast of French Polynesia) is travelling southeast and associated trough is expected to pass by Tahiti late this week, bringing small squalls and then a lull.
HIGH H1 near 25S over Queensland is expected to stretch eastwards and keep a weak subtropical ridge between 25 and 30S across the South Pacific. taking a southern route from South of NZ along 45S.
Low tonight to NE of New Zealand is expected to travel south along 180. From mid-week on its front a secondary Low L2 is expected to form near35S and south of the Cooks Islands (near 160W).
Low L3 is expected to form over inland Australia on Tuesday then cross the Tasman on Wednesday and NZ on Thursday. Later in the week is may expand into a multi-system trough east of NZ.
L3 is followed by HIGH H travelling along 3o to 40S S and reaching NZ around Sun/Mon 19/20 July.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 6 June 2025

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 6 July 2025

FNMOC is no more….

On June 25, 2025, the Trump administration issued a service change
notice announcing that the Defense Meteorological Satellite Program,
DMSP, and the Navy's Fleet Numerical Meteorology and Oceanography
Center would terminate data collection, processing and distribution of
all DMSP data no later than June 30. The data termination was
postponed until July 31 following a request from the head of NASA's
Earth Science Division.

The 2025 Atlantic hurricane season, which runs from June 1 to Nov. 30,
is forecast to be above average, with six to 10 hurricanes. The most
active part of the season runs from the middle of August to the middle
of October, after the DMSP satellite data is set to be turned off.
Hurricane forecasters will continue to use all available tools,
including satellite, radar, weather balloon and dropsonde data, to
monitor the tropics and issue hurricane forecasts. But the loss of
satellite data, along with other cuts to data, funding and staffing,
will make the forecasting harder.

A review of last month's weather

Here is a link to a YouTube clip giving an animated loop of the
isobars and streamlines in the South Pacific for the last month
youtu.be/y5BpNdbsX0E
Lows crossed NZ on 4-5, 12-13,20-21 and 27-28 June…. A weekly cycle
The Low on 27-28 brough heavy flowing to Tasman/Nelson/Marlborough
area and wind and rain damage to Taranaki.

The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern,

From http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.
shtml

Sea Surface temperature anomalies as at 30 May
from psl.noaa.gov/map/clim/sst.shtml
The build up of heat east of Japan an in the north Atlantic is
concerning.
The cooling /upwelling off Peru is interesting.

The monthly pressure pattern and anomalies are
from http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html

During June the sub-tropical ridge in southern hemisphere has widened
and shifted north. The heat low over Asia has intensified and
pressures have fallen over Siberia.

Pressure anomalies for past month Shows lows forming around south
Australia. Also, higher than normal pressures around Indonesia.  
The 1020 isobar has disappeared off NZ and shifted north (and shrunk)
over Australia.
The isobars are closer together over the Southern Ocean in June than
they were in May .

TROPICS

The latest cyclone activity report

Barry was a tropical storm for only about 12 hours after it formed in
Mexico's Bay of Campeche. It brought moderate rain to northeastern
Mexico.
• Hurricane Flossie intensified rapidly off Mexico's Pacific coast as
Typhoon Mun and Dunas formed near Japan.

WEATHER ZONES

Rain accumulation this week from Windy.com shows well defined SPCZ
between Solomon Islands and Samoa.  Also a passing trough south of
French Polynesia .

The wind accumulation shows NO squash zones in the tropics, but there
is a windy passing trough east of New Caledonia and south of Fiji.
Also, a windy zone associated with the passing trough south of Tahiti.

LOWS and HIGHS

HIGH H1 is taking a southern route from South of NZ along 45S.

Low L1 is an amalgam of several smaller lows all under one large upper
trough.  Some of these are the remains of the East coast low that
thrashed Sydney last Thursday.  It gets onto the western side of the
upper trough and thus is steered NE towards 25S before then turning
south again mid-week.  This is likely to bring a few days of northerly
then westerly winds to islands in Southern Cooks… not nice.

Not shown on that Wednesday map is a weak east coast low forming off
Sydney tonight then fading in Tasman Sea on Tuesday but associated
front and westerly winds bring strong winds to Tasman Sea south of
30S.

L1 is followed by H2 from central Australia but H2 fades away in north
Tasman Sea.

The reverse is expected further south, with L2 from the Australian
bight moving south of Tasmania by mid-week and forming a secondary L3
on its NW shoulder/ L3 then deepens in 3 days and travels across NZ
next Friday and weekend, keeping with the weekly pattern.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 29 June 20025

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 29 June 2025
WMO report on state of our planet in 2024
https://wmo.int/sites/default/files/2025-03/WMO-1368-2024_en.pdf
2024 was 1.55C above the 1850-1900 average and the warmest year in the
175-year observational record, beating the previous record set only
the year before.
One year over 1.5C does not indicate that the long-term temperature
goals of the Paris Agreement are out of reach but is a wake-up call.
The Antarctic sea ice reached the second-lowest extent ever recorded.

The observed ocean heat content reached a new record high. It has
increased by 16ZJ (ZITAJOULES) since last year. O if only we could
harness this. the human annual world energy consumption is measured to
be around 0.5ZJ

In 2024, the global mean sea level reached a record high in the
satellite record (from 1993 to present).

The minimum daily extent of sea-ice in the Antarctic region in 2024
was 1.99 million km2 on 20 February, which tied for the second lowest
minimum in the satellite era and marked the third consecutive year
that minimum Antarctic sea-ice extent dropped below 2 million km2.

There were droughts and floods but no obvious pattern in the rain.


TROPICS
The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
http://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

There are two tropical depressions tonight near the Mexican coast, TD6
on the west and TD2 on the east.
Super Hurricane Erick weakened to a Category-3 storm just before
making landfall on Mexico's Oaxaca state, killing one person in flash
flooding. Erick was the first storm on record of Category-3 force or
greater to strike Mexico before July.
. Tropical Storm Andrea, the first named storm of the Atlantic
hurricane season, formed briefly in the mid-Atlantic.
. Tropical Storm Sepat lost force before its remnants brushed the Jap

WEATHER ZONES
Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), STR (Subtropical Ridge), SPCZ (South Pacific
Convergence Zone) CZ (Convergence Zone)



Rain accumulation this week from Windy.com shows a well-defined South
Pacific Convergence zone over southern parts of French Polynesia.
Also, some heavy rain for Northland to Bay of Plenty and about coast
new South Wales from L2. And a rebuilding pf the SPCZ over Solomon
Islands

Wind accumulation this week from Windy.com shows a weak squash zone in
the tropics over Niue to Southern Cooks and a strong one over southern
Fresch Polynesia. Lows also have strong to gale winds around them.

LOWS and HIGHS
LOW L1 tonight is south of Chatham Islands and moving off to the east
along 45S to 40S and expected to be south of 155W by end of the week
HIGH H1 should briefly cross NZ on Tuesday and then move off to the
east quickly followed by NE winds between it and L2. Only quick yachts
can use this window to get from Northland to the tropics.
Low L2 is an east coast low deepening rapidly off coastal New South
Wales on Tuesday . Avoid the Tasman this week. Associated trough
should cross NZ on Friday.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world.
Compiled 22 June 2025
SOLSTICE and the state of Greenland Ice melt
The Solstice this weekend marked the longest day of the year in the northern hemisphere and the shortest in the southern.
At this time of the year the Pleiades cluster is visible in the eastern sky just before sunrise (so long night light is not swamped by a full moon). This is taken by Polynesians in the southern hemisphere to be the start of a new year. Their name for that cluster is MATARIKI. In New Zealand we celebrated MATARIKI with a Friday holiday and long weekend. Tahiti will celebrate its first Matari'i National Public Holiday in 2026. In Hawaiian culture, the star cluster is known as Makahiki and its rising is also considered the start of the new year for agricultural purposes.



After the solstice there is a thermal lag until ground temperatures reach their annual minimum. For the next six weeks we can say that when the "days get longer the cold gets stronger". In the northern hemisphere a similar heat lag occurs, and ground temperature do not reach their annual PEAK until "the dog days" when the dog star Sirus rises just before dawn. When stargazing, if you can find Orion's belt then look left and up to find Sirus and then look right and down almost twice as far to find Pleiades/Matariki/Matari'I/Makahiki.

So, we are just beginning to move into the period of maximum ice melt in Greenland.
Sadly, the data shows that we are already forming new maximum melt recordings.

See https://nsidc.org/ice-sheets-today
During a May heat wave Greenland's ice sheet melted 17 times faster than normal, according to a new report by World Weather Attribution. In Iceland, temperatures soared past 79 degrees, breaking records and straining infrastructure not designed for such warmth on the island.


TROPICS
Typhoon Wutip left at least six people dead in Vietnam from downpours and flooding. The storm also damaged crops on China's island province of Hainan. * The most active region for tropical cyclone development continues to be off Mexico's Pacific coast, with Tropical Storm Dalila passing offshore and Eric striking Acapulco as a Category-2 hurricane.

WEATHER ZONES
Weather Zones Mid-week GFS model showing isobars, winds, waves (purple), rain (red), STR (Subtropical Ridge), SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Rain accumulation this week from Windy.com shows a well-defined South Pacific Convergence zone from Solomons to Samoa.

Wind and rain accumulation this week from Windy.com show a storm on the back side of a low east of NZ. They also show an active squash zone between Niue and Tonga and then a tropical trough forming over Southern cooks after mid-week. Avoid.
LOWS and HIGHS
LOW L1 tonight has a 990hPa centre east of Auckland and south of Niue with gale winds near its centre. It is expected to move off to the SE.
HIGH H1 in central Tasman Sea is expected to also travel SE across north Island next few days mid-week. A squash zone of enhanced trade winds is expected between Niue and Tonga. Avoid.
Low L2 is expected to cross Tasmania on Tuesday and then stall over NZ from Thursday to Saturday..
HIGH H2 is expected to slowly spread across the Aussie Bight this week.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 15 June

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 15 June 2025
HOW TO EVADE THE WORST
The "Law of storms" or more pedantically correct "Law of Gyration,"
(or the law of the rotation of winds) was compiled in 1860s to help
sailing master mariners know which way to sail when encountering the
winds that rotate around storms. These were compiled soon after the
birth of weather maps with isobars and around 50 years before the
birth of weather maps with fronts.
Here is a link to the original article thanks to STARPATH
https://www.starpath.com/resources2/Practical_Matters_from_Dove.pdf
Around 30 years ago during the (in those days) Queens Birthday in
early June 1994 a fleet of yachts sailing from New Zealand to Fiji
encountered a deepening Low that formed off the southeast of Ne
Caledonia.
This became known as the "Pacific Storm" and prompted me to collect
together notes about South Pacific sailing as the MetService Mariners
Met Pack. This is still available at
http://about.metservice.com/our-company/learning-centre/mariners-met-p
ack/

As part of that booklet, I revisited Dove's "Law of storms" and
produced these two flow charts, reproduced in my illustrated
weathergram for your educational enjoyment at
https://metbob.wordpress.com/2025/06/16/bob-blog-15-june/



TROPICS
The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
http://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

Tropical Storm Wutip drenched South China's Hainan and Guangdong
provinces as the first named storm of the typhoon season. . Tropical
Storm Cosme , short-lived Hurricane Barbara spun up off Mexico's
Pacific coast followed by DELILA

WEATHER ZONES
Rain accumulation this week from Windy.com shows a well-defined South
Pacific Convergence zone from Solomons to Samoa.

Wind and rain accumulation this week from Windy.com shows enhanced SE
winds in the Coral Sea and around L1 east of New Zealand.
LOWS and HIGHS
LOW L1 tonight comprises of several tight centres forming under a jet
stream between 25 and 30S and in area north of NZ. These should gel
into one on Monday and then travel southeast and deepen in the
subtropics. There is likely to be a lull on the tropical side of L1
along with a passing trough over Niue on Monday/Tuesday and Southern
Cooks mid-week. This passing trough is looking to be mediocre in the
tropics. However, L1 has strong winds around it
HIGH H1 in south Tasman Sea is expected to spread across central NZ
mid-week and then travel east from 40S to 30S when east of NZ. After
Wednesday it may enhance the trade winds on its northern side,
especially between Niue and southern Cooks.
Low L2 is expected to cross Tasmania on Tuesday and then southern New
Zealand on Thursday followed by a southerly flow over NZ on Friday.
This is followed by H2 travelling between 30 and 40S crossing New
South Wales on Wednesday and northern NZ on Saturday/Sunday.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 8 June 2025
A review of last month's weather
A recent report summarises an investigation into how fast the planet's
land areas are heating up.
https://www.climatecentral.org/report/climate-change-and-the-escalatio
n-of-global-extreme-heat-2025

In particular it studies 67 extreme heat events in 247 countries in
the year ending 1 May 2025

The only areas with little change are the south coast of Australia,
parts of coastal Antarctica, a zone near Moscow, and spots in USA and
Brazil.

The study was able to calculate the contribution of Climate change,
using the Climate shift index. For more information on their
methodology please read the report.


Basically, the main impact of climate change on temperature is in the
equatorial zone.

TROPICS

Cyclone Barbara is travelling NW parallel to Mexican west coast and
expected to peel off to the west at 20S.
WEATHER ZONES
Rain accumulation this week from Windy.com shows a well-defined South
Pacific Convergence zone from Solomons to Samoa.
Wind and rain accumulation this week from Windy.com shows enhanced
SE winds in the Coral Sea and a well-defined squash zone near 25S
between Fiji and New Zealand.
LOWS and HIGHS
HIGH H1 is tonight centred on25S south of Fiji, and this week expected
to travel off to the east. Associated ridge may briefly cross New
Zealand on Monday night.
Deep Low now east of New Zealand is moving off to the east.
Low L1 is expected to form off southern New South Wales coast by
Monday and coast on Monday and deepen as it crosses NZ slowly from
Tuesday to Friday, with a southerly flow in Tasman Sea.
HIGH H2 in Aussie bight should move NE across New South Wales on
Thursday and weaken in the northern Tasman Sea by end of the week,
enhancing SE winds in the Coral Sea.
Gulf of Panama: light winds becoming mainly SW 15 to 20kt.
8N to 2N: Squally often westerly or SW winds and a sea drifting to
east
2N to Galapagos: Winds from between SE and S and a sea drifting to the
NW/west
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.

Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.

Compiled 1 June 2025

A review of last month's weather

Here is a link to a YouTube clip giving an animated loop of the
isobars and streamlines in the South Pacific for the last month at
youtu.be/TZUof6eDnBY

The highlight of the month for the South Pacific tropics was a chain
of lows that formed around 10 May.  Further south it was a series of
Lows and Highs

The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern,

From http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.
shtml

Sea Surface temperature anomalies as at 30 May
from psl.noaa.gov/map/clim/sst.shtml

The Galapagos area is now showing warm anomalies.

There is a cold anomaly along the Canadian east coast

Also stronger upwelling and cold water off Baja California.

The Kuroshio current is warmer than normal..

From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html

During May the main changes have been season.  The Sub tropical ridge
in southern hemisphere has weakened. The heat low over Asia has
intensified and pressures have risen over Siberia.

Pressure anomalies for past month (below)

Shows the reversal of those anomalous  April lows in Tasman Sea and
mid-South Atlantic,.


The 1020 isobar has shifted northwards .

TROPICS

The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is
from http://www.ospo.noaa.gov/products/ocean/tropical/tcfp/

A quiet time for tropical cyclones. Tropical Storm Alvin, the first
named storm of the eastern North Pacific hurricane season, formed off
the coast of southern Mexico.

WEATHER ZONES

Rain accumulation this week from Windy.com shows well defined SPCZ
between Solomon Islands and Samoa.  Also a passing trough near French
Polynesia.

Wind and rain accumulation this week from Windy.com

The wind accumulation shows a small squash zone ner Southern Cooks on
north side of a traveling High mainly on 4 and 5 June. Also bands of
strong winds off east of NZ around a deep low mainly after Wednesday.
 

LOWS and HIGHS

HIGH H1 has been crossing by north of NZ today and is expected to
travell east along 30 to 35S stalling south of French Polynesia late
in the week

 Low L1, is expected top form off Queensland coast on Monday and
deepen crossing NZ on Thursday and Friday then lingering east of NZ at
end of the week with a southerly flow over NZ.

HIGH H2 in Aussie bight should move NE across New South Wales on
Thursday and weaken in the northern Tasman Sea by end of the week.

LowlL2 should follow H2, reaching New South Wales at end of the week.

Gulf of Panama:   SW 10kt becoming light winds after Thursday, but
oulook next week  is for SW up to 20kt .

6N to 2N: Showery, often westerly or SW winds and a sea drifting to
east

2N to Galapagos: Winds from between SE and S and a sea drifting to the
NW/west

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 

If you would like more details about your voyage, check metbob.com

Or Facebook at /www.facebook.com/metbobnz/

Weathergram with graphics is at metbob.wordpress.com

(subscribe/unsubscribe at bottom).

Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.

Contact is bob@metbob.com or text 64277762212.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt' ideas for sailing around the South Pacific.

Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 25May 2025

Tahiti to Tonga
Now that many yachts are about to travel west from Tahiti to Tonga, it
is time to review the weather, in general terms, for this route.

The main players:
1. Getting from the Tahiti area to Tonga/Fiji means crossing the South
Pacific Convergence zone, SPCZ
This zone may be weak or may contain squally showers. In the models it
is portrayed as a zone of light winds. To see a forecast for this
zone, use windy.com and rain accumulation for a period over five days.
This zone may linger in the north (it does this in an El Nino, or it
usually hovers between Samoa and Southern cooks. To avoid it choose a
different latitude or aim for gaps in the zone.
The SPCZ goes thru periods of activity and inactivity and is active
when there is the positive phase of an MJO (Madden Julian
Oscillation).
Occasionally a tropical low/passing trough will travel east/southeast
along the zone, making for a burst of wind/rain travelling east from
Fiji to Niue then SE across Southern cooks. These occur on occasions
even at this time of the year and can be forecast beforehand and
avoided.

2. Another thing to avoid is a SQUASH ZONE when a large High travels
east along 30S.
When the central pressure in the High is 1030hpa or above, it gets
dirty (above ten thirty is dirty) and squeezes the isobars north of
the high in the trade wind zone closer together making a "squash zone"
of enhanced winds and rough seas. These usually occur around 20 to 25
South and may last for several days. They are reasonably easy to
forecast and are worth avoiding. If caught in one, change your
latitude rather than your longitude.

3. The third thing to avoid is the PASSING TROUGH or passing low.
The systems tend to form on the eastern end of the SPCZ in which case
they travel southeast, propelled by upper NW winds as a steering
field. OR they may form on the NW (back) corner of a travelling HIGH.,
in which case they may get shunted south or sometime to the southwest.
They often have their own mini-squash zones (on their polar/southern
side), and calm zones (on their equatorial/northern side). Isobars
give a clue about the intensity of a passing trough: those above
1010hP are usually weak and those below 1007 are worth avoiding.

There are three routes between Tahiti and Tonga, the northern, central
and southern:

Sometimes the northern route via Suwarrow/Samoa is favoured, and
sometimes not.
The northern route goes via Suwarrow to Samoa. Often this is covered
by the SPCZ, but when the SPCZ is further south the northern route and
its northeast winds may be best.

The middle-route offers stopovers such a Palmerston Island and Niue
and is a good alternative when the SPCZ is further north. Watch out
for passing troughs and squash zones … these come and go. The middle
route allows short hops.

The southern route tends to get higher swells from the Southern Ocean

 SO, all in all, the "best voyage" changes every few days … sometimes
it's worth waiting for something that suits, sometimes it isn't.

Basically, avoid passing troughs and squash zones, and go thru the
SPCZ when it is weak. This may mean taking short hops rather than
getting direct from Tahiti to Tonga in one go.

=-=-=-=-=-=-=-=-=-=-=-

Onset of this year's Indian Monsoon
This week the monsoon is advancing onto southern Indian (blue lines
below)

It is around 7 to 10 days earlier than normal
From https://mausam.imd.gov.in/imd_latest/contents/monsoon.php

TROPICS


Last week an unnamed tropical storm spun up for a few hours along the
southern coast Another quiet week but note the potential areas around
India due to the early Monsoon, and hints of potential off Mexico west
coast. Also, a strange blob of potential around Niue, where L1 forms
this week.

WEATHER ZONES

Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge),
SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)

Wind and rain accumulation this week from Windy.com

Rain accumulation this week from Windy.com shows weak SPCZ and blobs
of rain with L1 and near Niue. Also -- Jet driven rain with L2
especially over South Island. A large DRY zone over New Caledonia,
Vanuatu and Fiji.

The wind accumulation shows a windy zone attached to L2 when it is
east of New Zealand. After the recent squash zone over Minerva, this
week is looking quiet especially around New Caledonia, Fiji and Tonga.

LOWS and HIGHS

HIGH H1 spent last few days over Tasman Sea and New Zealand. It helped
form last week's EASTIE which turned BEASTERLY over New South Wales.
H1 is this week expected to exit stage right and migrate off to the
east.

Low L1 and its associated troughs is expected to form on the NW corner
of HI, forming east of Niue and travelling south to southwest around
H1. Avoid.

Low L2 bred in the Southern Ocean and isa well supported feature
driven by jet streams feeding moisture into it from the Indian Ocean.
After going thru the normal 3-day life cycle of a low in the
Australian bight it is expected to do another three-day life cycle as
it crosses NZ Tuesday to Thursday dropping to below 980. Avoid.

Gulf of Panama: Just light winds Healthy current going to South then
west.

Panama to 2N: Squally convergence zone. South of 6N there is a strong
east to NE going current.

2N to Galapagos: Southerly winds, and sea drifting to the N or NW.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 18 May 2025

The QBO (stratospheric Quasi Biennial Oscillation)
Last week in my weathergram I showed that our recent South pacific
cyclone season was one of the quietest ever. Maybe the QBO can partly
explain this
The Quasi-Biennial Oscillation (QBO) is a natural climate pattern
that causes a shift in the direction of the equatorial stratospheric
winds, switching between easterly and westerly winds. These winds are
read twice daily by radiosondes released from Singapore. This
oscillation, with an average period of about 28 months, can have an
impact on weather patterns and is considered a valuable component of
long-range weather forecasting.

From acd-ext.gsfc.nasa.gov/Data_services/met/qbo/qbo.html
During the last cyclone season the equatorial stratosphere had
westerly winds. more than normal, and there was a slightly lower
troposphere than normal. These factors make it harder for tropical
cyclones to develop.
TROPICS

This week the monsoon is advancing onto southern Indian (blue lines
below)
From mausam.imd.gov.in/imd_latest/contents/monsoon.php

WEATHER ZONE

Wind and rain accumulation this week from Windy.com
The wind accumulation shows a windy zone attached to that "Eastie"
which briefly forms off the New South Wales coast, and a lot of
southerly winds onto Chatham Island east of NZ, on the back end of L1
There is also zone of enhanced trade winds mainly between 20 and 25S
south to south of Fiji.

The rain accumulation also shows a rain band associated with "Eastie"
and a rather uniform SPCZ north of Fiji
LOWS and HIGHS
Low L1 and its associated troughs has got east of New Zealand today
and Monday and is expected to travel steadily eastwards this week.

HIGH H1 is over Bass strait tonight and expected to take its time
travelling east across the Tasman Sea then cross central NZ next
weekend. By then it will have a weak squash zone in the trade winds on
its north side. GFS has a trough/low forming near Minerva reef
Mon/Tue 26-27 May but other models disagree. Watch that space and be
prepared to brace accordingly.

Gulf of Panama: Just light winds Health current going to SW.
6N to 2N: Not as showery as last week South to SW winds. Variable
currents
2N to Galapagos: Winds from S/SE and sea drifting to the WNW.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram 11 May

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 11 May 2025
A review of the cyclone season

We can compare the timing of these cyclones with the active phases of
the MJO on the South Pacific shown here in Blue.

The 2024–25 South Pacific cyclone season was one of the least active
seasons on record within the South Pacific Ocean to the east of 160°E.
Just four named storms formed (compared with an average of 7). None
intensified into severe tropical cyclones, the first such failure
since the 2008–09 season.

TROPICS
A second quiet week for tropical cyclones world-wide.

WEATHER ZONES

Rain accumulation this week from Windy.com shows well defined SPCZ and
blobs of rain with L1
The wind accumulation shows a windy zone attached to L1 as it moves
out of the tropics. Only patches of wind in the Tasman but a period NW
winds late in the week for eastern North Island.

LOWS and HIGHS
Low L1 has formed tonight just south of Fiji with an active wind and
rain band over Minerva and Tonga tonight and Monday then moving ESE to
reach Southern Cooks on their local Monday and Tuesday. Stay put for
that.

A FRONT with strong westerly winds is crossing south end of NZ on
Monday and then travelling east to merge with L1. This gives a SW
flow over NZ on Monday and a weakening southerly on Wednesday.
Large HIGH H1 in Tasman Sea expected to stay put until mid-week then
cross central NZ on Wednesday and travel off to the east from
Thursday/

The Trough following this HIGH should reach Tasmania on Wednesday and
NZ on Sat/Sun as a well-formed Low.
HIGH H2 in Aussie Bight by mid-week is expected to spread east onto
Melbourne area this weekend.

Gulf of Panama: Maybe some useful northerly winds on local Monday
else light winds or southerly winds. Health current going to SW.
6N to 2N: Showery, South to SW winds. Variable currents
2N to Galapagos: Winds from SE and sea drifting to the WNW.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bob blog

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.

Compiled 4 May 2025

A review of last month's weather

Here is a link to a YouTube clip giving an animated loop of the
isobars and streamlines in the South Pacific for the last month at
youtu.be/M72SdfJhSnk

In Mid-April Cyclone TAM formed near Vanuatu and travelled south into
the Tasman Sea where it was held in place for several days by a HIGH
east of NZ, affecting NZ on the approach of Easter.

Then at the end of the month another LOW from the Tasman Sea
explosively deepened near Cook Strait bringing floods to Christchurch
area and damaging winds to Wellington

The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern, with the Highs showing either wave 2 to 3

Sea Surface temperature anomalies as at 2 May
from psl.noaa.gov/map/clim/sst.shtml
show that The Galapagos area is now showing some warm anomalies.
And there is a cold anomaly along the Canadian east coast.
Around 85percent of the globe is showing warm anomalies.

From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html

A ridge has turned into a trough in the Tasman Sea, else just small
differences from last month.

Pressure anomalies for past month shows deep anomalous lows in Tasman
Sea and mid-South Atlantic, and a switch from trough to ridge over
USA.

The 1010 isobar has retreated off Australia.
The northern 1015 line has moved north across Australia, but south in
the Tasman Sea.
The southern 1015 line is in much the same position.

TROPICS
A quiet week for tropical cyclones

WEATHER ZONES
Rain accumulation this week from Windy.com shows well defined SPCZ and
blobs of rain with L2 and L4
The wind accumulation shows a squash zone between 20 and 25S from near
Vanuatu to Southern Cooks. It also shows strong northerly winds near
NZ with L2.

LOWS and HIGHS

Low L1, the remains of the low that affected wellington and
Christchurch last Thursday, is travelling off to the east

HIGH H1 travelling east across central NZ next few days is expected to
form a squash zone of strong east to SE wind on its northern side
between 20 and 25S. Avoid.

Low 2 is expected to form over Vanuatu area late in the week and might
travel as a trough towards Northland this weekend as low L3 travels
east across southern NZ.

Since L2 might turn the winds between NZ and Tonga to be from NE late
this week it may be more comfortable to wait until early next week or
when this threat passes away before departing Northland for the
tropics.

now south of Southern Cooks is moving slowly SE.  Associated trough is
expected travel from Niue to Southern Cross this week, and the
southerly swells on its backside are expected to reach French
Polynesia late in the week.

HIGH H2 is expected to move into Tasman Sea by end of this week.

And there is expected to be a low L4 forming south of Tahiti by end of
the week.

Gulf of Panama:  Maybe some useful northerly winds from 8 to 15May,
else light winds.
Some light winds next few days then useful NE winds after Tuesday.
Showery.
6N to 2N: Showery, often westerly or SW winds and a sea drifting to
east
2N to Galapagos: Winds from between SW and S and a sea drifting to the
NW.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Bobgram

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 27 April 2025

WESTWARD HO … for those planning to get from Tahiti to Tonga

An introduction to the South Pacific Convergence Zone (What and Why)

Now that the cyclone season finishes mid-week, many yachts are about
to travel west from Tahiti to Tonga, and are thus about to sail thru
or around the SPCZ, this obstacle has become a talking point…as if it
guards the eastern entrance to the South Pacific like a protective
dragon or demon, and some have asked what is it, why is it there, how
does it differ from the ITCZ and what makes it tick.

Weather is a mix of pattern and chaos, and meteorologists concentrate
on the pattern.
In tropical meteorology the first idea given is the Hadley cell.

Recipe for the ITCZ

Because the sun is most directly overhead near the equator, that's
where the warmest seas are, and this causes rising air. 

Once the rising air reaches high enough it spreads outwards and
sideways to the north or south, where it sinks at dries out. 

The sinking air reaches the surface again around 30N or 30S
(subtropical ridge) and then recirculates back to the equator as
surface winds know as trade winds. 

The trade winds from each hemisphere converge together in a zone, and
this convergence narrows the zone of rising air into a feature called
the Intertropical Convergence Zone or ITCZ

But in the Southern Hemisphere, the Andes of South America cause a
split in the trade winds. They block a HIGH near 30S around 90 to
110W, or south of Easter Island.  It is quasi stationary, just like
the High between California and Hawaii, and has a gyre that collects a
rubbish heap just as badly (see Henderson Island: 
blogs.fco.gov.uk/lauraclarke/2018/04/10/henderson-island-plastic-pollu
tion-in-paradise/).

Recipe for the SPCZ
There are easterly winds on the north side of this "Andes" High: they
are dry due to continental outflow from off South America.   These
easterly winds travel well to west of the dateline along around 10 to
15S.

 And there are migratory Highs that travel east along the subtropical
ridge from Australia to east of NZ, with a zone of south to southeast
winds on their northern side. These South/SE winds come and go
according to the migratory high and are usually found around 15 to
25S. 

The convergence zone between these easterly and Southeasterly winds is
called the South pacific Convergence Zone, or SPCZ.

It is typically located from the Solomon Islands south-eastwards to
the Southern Cooks, and is around 1 to 5 degrees latitude wide, but
sometimes may have large gaps or be very quiet.

It is affected by many things:
the Pacific Decadal Oscillation or PDO which takes many years to
switch.
the El Nino/La Nina which lasts a year or so.
the strongest cycle is the ANNUAL cycle as earth orbits the sun,
making the seasons.
and the MJO which comes for a week or so every six weeks or so.
Read more about it at
en.wikipedia.org/wiki/South_Pacific_convergence_zone

see www-gte.larc.nasa.gov/pem/pemt_flt.htm

I have found that the easiest way to determine the position and
severity of the SPCZ is to use satellite imagery, and the easiest way
to decide what it may do over next few days is to use the 5day rain
accumulation parameter on windy.com.

The latest Satellite image of the SPCZ is available as a small
attachment via an email request.

Send an email to query@saildocs.com with the message (no subject line
needed)

SEND  https://www.y2ksail.com/himawari/latest-SpacificLarge-small.jpg

Max puts together the Y2K links page and has recently updated it at
https://www.y2ksail.com/meteo-link.html

In a future blog I'll compare and contrast the three routes from
Tahiti to Tonga: when to take or avoid the northern, direct or
southern route and how to decide which is best over the week ahead.

NORTHWARD HO

Those gearing up to depart Northland. New Zealand for the tropics will
be often arranging a voyage across the subtropical ridge into the
tropics.

Usually, a good weather pattern to depart is in the SW flow found on
the back end of a passing trough/front/low as it moves off the east or
southeast of Northland.

However, if the following HIGH is TOO FAR south, as is the case this
week, then it may build east of New Zealand and make a squash zone of
strong east to NE winds near Tonga within a week after departure.
 Avoid these departures.

TROPICS

The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
www.ospo.noaa.gov/products/ocean/tropical/tcfp/

There are no named Topical cyclones around at present.

Subtropical Storm Kanto formed well to the south of Madagascar as the
first such system in the region since Issa spun up during the southern
Indian Ocean's 2021-22 cyclone season. While Kanto formed far from
land, Issa caused significant death and destruction in parts of South
Africa.

 • After reaching Category-5 force for a few hours, Super Cyclone
Errol weakened to a minimal tropical storm before making landfall on
Australia

WEATHER ZONES

Wind accumulation shows windy conditions south of 30S  and a squash
zone developing in Coral Sea,

Rain accumulation this week from Windy.com shows a rather weak SPCZ 
and  a trail of rain with L1 also a wet trough southeast of Society
Islands/Tahiti.  

LOWS and HIGHS

 The High H1 south of Tahiti and near 40S should exit stage right this
week and allow Low L1 which has formed off eastern New South Wales to
slowly travel east toward Northland by Tuesday and then off to the
southeast.  There is a good voyage from Brisbane to Noumea riding on
the backside of L1.

Watch H2 which follows L1.  It is expected to reach central Tasman Sea
this weekend.  It is too far south to allow for a n easy voyage for
Northland to the tropics after L1.

Already by this weekend is expected to cause a squash zone in the
Coral Sea. And next week it may cause a squash zone or a new trough
over Tonga. There are several options and some of them allow an OK
voyage departing Northland around Wed or Thursday, but most options
don't.,

Gulf of Panama:  OK Northerly winds until Wednesday then light winds.

5N to Galapagos:  The convergence zone with squally showers and light
winds in-between them is from 6N to 2N. SW to S winds this week are
likely south of 3N.

Current around Galapagos are strong and this week go to the west.

Avoid the HEAD current near 5N 83W

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 
If you would like more details about your voyage, check metbob.co
Or Facebook at /www.facebook.com/metbobnz
Weathergram with graphics is at metbob.wordpress.co
(subscribe/unsubscribe at bottom)
Weathergram archive (with translator) is at weathergram.blogspot.co.nz
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>

Bobgram 20 April

Bob McDavitt's ideas for sailing around the South Pacific.
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 20 April 2025
Ten Tips for Weather Comms while Cruising South Pacific
TEN TIPS FOR CRUISING SAILORS
Now that cruising sailors are on their final preparations for
departing New Zealand for the warmth of the tropical Islands, 'tis is
a good time to review the ways to obtain weather forecasts and/or
provide position reports when at sea.
1. ZLM/Taupo Maritime Radio offer a continuous 7/24 Trip
reporting service, see
www.maritimenz.govt.nz/about/what-we-do/safety-and-response/maritime-r
adio.asp
The HIGH SEAS forecast for the area SUBTROPIC from MetService is read
out in English via ZLM at 0903hr, and 2103hr NZST/NZDT on 6224 and
12356KHz and repeated an hour later on 8297 and 16531 KHz.
(www.metservice.com/marine/radio-schedule)
NZ MetService ceased their ZKLF Radio fax 1 July 2023
Australia's Bureau of Meteorology still sends weather maps by HF Radio
fax. The nearest transmitter to the South Pacific is VMC in
Charleville, schedule is at
www.bom.gov.au/marine/radio-sat/radio-fax-schedule.shtml
2. Gulf Harbour Radio ZMH286 check in service with weather.
Patricia and David keep track of boats that listen to their
rollcall/weather service. Firstly, contact them via email or radio
with your details - boat name, MMSI, boat type and length. Then let
them know when you are about to take off and whether you will be on
air each night. They operate on 8752USB at 0515 UTC which is 5:15pm
NZST and an hour later during daylight saving, 6:15pm. Each broadcast
is live streamed so friends and family can hear your check in and
follow along. David gives a weather update each night for the passage
routes and the islands. And there are articles of general interest and
specifically on weather in their web site, www.ghradio.co.nz
ghradio@xtra.co.nz
3. Passage Guardian passageguardian.nz
peter@passageguardian.nz
Passage Monitoring is operated by Peter Mott and provides a global
free-of-charge service (donations welcome) that monitors the progress
of recreational vessels conducting ocean passages.
Peter uses a range of tools, including satellite trackers, AIS and
email, and multiple maritime radio frequencies to keep a constant
watch on yachts that have filed a float plan prior to departure. The
service has a formal policy for dealing with a missed check in.
Whilst available to all yachts, Passage Monitoring is especially
suited to shorthanded and solo sailors, in particular
circumnavigators.
4. AMATEUR RADIO/Ham net: PACSEANET pacseanet.gmail.com
The Pacific Seafarers Net is a ham (amateur radio) network providing a
free of charge check in service on amateur frequency 14300KHz USB in
the 20-metre band at 0300UTC. To participate, operator needs to hold
an Amateur Radio Operators Certificate (General class or above). In
the amateur radio service, the callsign is assigned to the licensed
operator, so this is a different callsign from using a maritime
callsign. Position reports are received and reported in the well-know
YOTREPS format (but missed calls may not be followed up). They have 12
listening station dotted between Australia and Alabama. See
pacseanet.blogspot.com
5. EMAIL via HF requires a PACTOR modem See
https://sailmail.com/

6. INTERNET via EMAIL
if you only have email, Saildocs (saildocs.com) relays details of a
TEXT BASED webpage. See weather.mailasail.com/Franks-Weather/Home
They allow you to download, e.g., the latest Fiji Met Service High
Seas by sending an email, no subject necessary, to query@saildocs.com
with message: SEND http://www.met.gov.fj/aifs_prods/10140.txt
For a list of useful links see https://www.y2ksail.com/meteo-link.html

7.. Fiji Fleet code. How to download a map via HF (thru email)
This is real old school stuff, but it still works if you need it.
To download the latest Nadi Fleet Code, send an email to
query@saildocs.com, no subject needed, saying SEND nadi-fleetcode
Or SEND https://tgftp.nws.noaa.gov/data/raw/as/asps20.nffn.txt
This can be viewed within the Fleet Code plug in OpenCPN.
Download this at opencpn.org/OpenCPN/info/downloadopencpn.html
Open the email and select and copy the data (right click, Contral A
then Control C on a PC). Then, in OpenCPN's Fleet code plugin, there
are 4 options: Files, Text, Raw and Downloads. Select Raw and then
<paste> or CTRL-V and Voila! the map appears.
I still have a copy of the old, no longer supported Fleet code viewing
program call Phys Plot. If you want to try it, let me know.
8. Smart phone apps: Some satellite phones now provide Wi-Fi that
allow nearby smart phones to use apps.
www.predictwind.com provides an app that supplies forecast model
data, observations and, at the Professional Account level, tools for
routing and comparing departure dates. It also has a position
tracking tool and can help with iridium Go! and some other GPS
devices. A moderate subscription gives access to its universal AIS
package with a regional search option.
9. The Windy.com App has a free basic option. It also has a
subscription option that can be used to compile route plots.
To make one: - "right click" anywhere on the map, this will open a
small context window. - choose "Distance & Planning"; - place your
points on the map; chose 'Boat' and enter your average likely speed,
click on "more options" bottom left and in the "table of points" you
just made, click the button label "share" in the bottom right corner;
- remember and use the short URL link provided or the long URL in the
top of your browser. You can also make one by building the URL
manually if you are familiar with this. Each time you plug this URL
in your browser, Windy will show the map and your planned route.
Shift the start time to see which gives the best voyage.
10. YiT, Yachts in Transit, at www.yit.nz or mike@yit.nz has a
smart phone app, and offers a subscription service to plot your
reports and blogs on the web and to request weather information via
coded emails. They also provide info on how to use iridium Go!, YB
Tracking, or Garmin inReach for communications. This site was closed
for a while but is back again this year.


TROPICS
The latest cyclone activity report is at zoom.earth and
tropic.ssec.wisc.edu and Tropical Cyclone Potential is from
www.ospo.noaa.gov/products/ocean/tropical/tcfp/

There are no named Topical cyclones around at present. Tropical
Depression 31 is heading for top end of Queensland.
Cyclone Errol exploded in strength to Category-4 force between Bali
and northwestern Australia. It drifted southeast-ward and weakened
before striking the Australian coast near Broome during the following
week. Tropical Storm Tam drenched much of the Vanuatu archipelago
without inflicting significant damage. But its remnants later knocked
out power and triggered local flooding across New Zealand's North
Island.
WEATHER ZONES
Weather Zones Mid-week GFS model showing isobars, winds, waves
(purple), rain (red), MT (Monsoonal trough), STR (Subtropical Ridge),
SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone)




Wind accumulation shows a demarcation line along the SPCZ. Also, the
track of L1 leaves a wind trail.

Rain accumulation this week from Windy.com shows heaviest rain may be
near northern Australia and along the SPCZ. A dry slot between BZ and
Fiji/Tonga.


LOWS and HIGHS
The remains of Cyclone TAM are finally moving across N Z on Monday.

The High H1 south of Tahiti and near 35S is quasi-stationary this
week and shepherding a small Low L1 from near Kermadecs southwards
then southeast-wards bringing a southerly flow to NZ on Tuesday, an OK
pattern for departing Northland for Fiji/Tonga.

However, by mid-week small lows on the SPCZ may form, L2 near southern
Cooks and L3 near Vanuatu.
L3 can make for stronger E to NE winds in area north of NZ by the
weekend so if you are unable to make a Tuesday departure from NZ then
for comforts sake it may be better to wait for next agreeable pattern
High H2 from Aussie Bight is expected to cross southern Tasman Se and
central NZ on Thursday and Friday then build east of NZ this weekend
with a squash zone on its northern side.

Gulf of Panama: Light winds until local Monday then useful NE winds
for several days
5N to Galapagos: The convergence zone with squally showers and light
winds in-between them is from 6N to 2N. Light south to southeast winds
around Galapagos.
Current around Galapagos is mainly from SE. Avoid the HEAD current
near 5N 83W
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, check metbob.com
Or Facebook at /www.facebook.com/metbobnz/
Weathergram with graphics is at metbob.wordpress.com
(subscribe/unsubscribe at bottom).
Weathergram archive (with translator) is at
weathergram.blogspot.co.nz.
Contact is bob@metbob.com or text 64277762212.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>