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 30 March 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/BeSWQwlK3qg
At the start of MARCH an MJO was affecting the South Pacific and
Cyclone ALFRED brought damaging wind and rain to the Brisbane area.
By mid-month the MJO moved on, but for the rest of the month a
monsoonal trough affected inland Australia and large anticyclones
travelled across central NZ.
March 2025 with its well-defined highs in the Tasman was a very good
weather pattern for Kiwi Grant "Axe' Rawlinson and Tasmania Luke
Richmond to row from Northland, NZ to Coffs harbour, arriving at beer
o'clock last Friday.
www.nbnnews.com.au/2025/03/29/record-breaking-row-across-tasman-sea/
axeoneverest.com/2025/03/28/tasman-2025-success-arrived-survived/
The trip took 22 days 4 hours and 40 minutes, and that's about 9days
faster than the 2007 trans-Tasman row.
The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern, with the Highs showing either wave 2 or wave 4 ,
briefly wave 3, see
http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_sh_anim.shtm
l
Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
show that the Galapagos area is now showing some warm anomalies.
There is a cold anomaly along the Canadian east coast. Around
80percent of the globe is showing warm anomalies.
At http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
The Aleutian low and Greenland lows have relaxed since last month.
The subtropical ridges in both the Northern and Southern hemisphere is
well defined.
Pressure anomalies for past month (below)
The anomaly pressure pattern shows the monsoonal trough over
Australia.
The 1020 isobar covers the Tasman Sea.
The 1015 line has moved north across southern Australia
The 1010 isobar has retreated from Fiji westwards to Queensland.
TROPICS
Cyclone COURTNEY is over the open Indian Ocean.
WEATHER ZONES
Rain accumulation this week from Windy.com shows heaviest rain with L2
on South Island north and west coasts. Avoid.
The wind accumulation shows where to avoid the trails of wind mapped
out by L1 and L2
LOWS and HIGHS
Low L1 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 H1 should travel east from South Tasman Sea to eats of the North
Island blocking L2
Low L2 is an east coast low that formed off Sydney today. It is
trapped in the Tasman Sea and is expected to finally cross Southland
area late this week. Avoid.
HIGH H2 is expected to maintain a ridge in the Australian Bight.
Low L3 is contained within the Monsoonal trough over inland Australia.
It is expected to become an East coast low off Brisbane o Wednesday
and then cross North Island late Friday followed by a westerly flow.
Gulf of Panama: Some light winds next few days then useful NE winds
after Tuesday. Showery.
5N to Galapagos: Light winds often from behind. Good tail currents
towards 2N, but a head current to the east about the Galapagos.
Showery south of 2N
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
30 March 2025
23 March 2025
Bobgram 23 March
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 23 March 2025
WMD
Today is the 75th World Meteorological day
On 23 March each year all meteorologists around the world commemorate
the commencement of WMO on this date in 1950.
The weather does NOT acknowledge any national boundaries and to gather
a working knowledge of what's happening we need observations from all
nations. Hence the WMO is needed to settle standards of observation
and share all weather data for our mutual benefit.
It has become a day whereby WMO can educate us all about important
matters. This year's theme is "Closing the early warning gap
together".
Over the past decade Governments around the word have been working on
how to get severe weather warnings enacted as quick and effectively as
possible. Even though the number intensity and cost of severe weather
events has been trending UP, the number of fatalities has been much
the same or even falling
WMO is now at the halfway mark of their Early Warnings for All
initiative, and significant progress has been made in saving lives,
protecting livelihoods, and strengthening community resilience. As
climate risks escalate, the urgency of the initiative continues to
grow.
These numbers show where we are
55%
As of 2024, 108 countries report having some capacity for multi-hazard
early warning systems, more than double the 52 countries in 2015.
Vulnerable Nations Progress
The least developed countries have shown the most significant
improvements, with landlocked developing countries and small island
developing states also surpassing the global rate.
+39%
The global average score for the comprehensiveness of multi-hazard
early warning systems has risen from 0.35 to 0.49, an increase of 39%.
Here is a link to a You Tube video on Severe Weather Warnings
https://youtu.be/35FvB7lst6o
"EVERY DOLLAR SPENT ON EARLY WARNING SAVES ON AVERAGE TEN DOLLARS IN
AVOIDABLE LOSSES."
TROPICS
. Tropical Storm Jude: After leaving at least nine people dead in
Mozambique and Malawi during the previous week, it drifted back over
the Mozambique Channel, where near-record high sea surface
temperatures fueled its regrowth. Jude then drenched southern
Madagascar, becoming the third tropical cyclone to rake the same
region so far this year.
. An unnamed tropical storm spun up near Australia's remote Cocos
Islands Indian Ocean territory.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ and
the heavy rain especially from NW Australia to Queensland. Yes, we
have the extra oomph of a MJO over northern Australia this week and
YES, it is expected to cross the Pacific over the following two weeks.
Wind accumulation this week from Windy.com
The wind accumulation shows a white trail with the Low in the Indian
Ocean. There is also extra wind and swell associated with the low near
the Kermadecs.
LOWS and HIGHS
Low L1 is expected to form just east of the Kermadecs by Tuesday and
then travel southeast this week
Hights H1, H2 and H3 are located between 40 and 45S and by mid-week
should be near 145W, 160E and 120E -consistent with a steady "wave 4"
around the planet.
The trough between Highs 2 and 3 is expected to cross NZ on Thursday
with some brief rain and a one-day southerly.
The SAM index/AAO index is positive and its trend this week is to
remain positive, so the fronts and SW wind bursts are not expected to
get far north this week.
High H1 in Tasman Sea is expected this week to travel across NZ on
Wednesday and Thursday. Before this there is a weak cold front/SW
change on Monday and Tuesday, but this is expected to weaken.
Panama Gulf to Galapagos: Good NE winds for starters and to 5N then OK
easterly or light winds and a good tail current to Galapagos.
Scattered tropical showers.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 23 March 2025
WMD
Today is the 75th World Meteorological day
On 23 March each year all meteorologists around the world commemorate
the commencement of WMO on this date in 1950.
The weather does NOT acknowledge any national boundaries and to gather
a working knowledge of what's happening we need observations from all
nations. Hence the WMO is needed to settle standards of observation
and share all weather data for our mutual benefit.
It has become a day whereby WMO can educate us all about important
matters. This year's theme is "Closing the early warning gap
together".
Over the past decade Governments around the word have been working on
how to get severe weather warnings enacted as quick and effectively as
possible. Even though the number intensity and cost of severe weather
events has been trending UP, the number of fatalities has been much
the same or even falling
WMO is now at the halfway mark of their Early Warnings for All
initiative, and significant progress has been made in saving lives,
protecting livelihoods, and strengthening community resilience. As
climate risks escalate, the urgency of the initiative continues to
grow.
These numbers show where we are
55%
As of 2024, 108 countries report having some capacity for multi-hazard
early warning systems, more than double the 52 countries in 2015.
Vulnerable Nations Progress
The least developed countries have shown the most significant
improvements, with landlocked developing countries and small island
developing states also surpassing the global rate.
+39%
The global average score for the comprehensiveness of multi-hazard
early warning systems has risen from 0.35 to 0.49, an increase of 39%.
Here is a link to a You Tube video on Severe Weather Warnings
https://youtu.be/35FvB7lst6o
"EVERY DOLLAR SPENT ON EARLY WARNING SAVES ON AVERAGE TEN DOLLARS IN
AVOIDABLE LOSSES."
TROPICS
. Tropical Storm Jude: After leaving at least nine people dead in
Mozambique and Malawi during the previous week, it drifted back over
the Mozambique Channel, where near-record high sea surface
temperatures fueled its regrowth. Jude then drenched southern
Madagascar, becoming the third tropical cyclone to rake the same
region so far this year.
. An unnamed tropical storm spun up near Australia's remote Cocos
Islands Indian Ocean territory.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ and
the heavy rain especially from NW Australia to Queensland. Yes, we
have the extra oomph of a MJO over northern Australia this week and
YES, it is expected to cross the Pacific over the following two weeks.
Wind accumulation this week from Windy.com
The wind accumulation shows a white trail with the Low in the Indian
Ocean. There is also extra wind and swell associated with the low near
the Kermadecs.
LOWS and HIGHS
Low L1 is expected to form just east of the Kermadecs by Tuesday and
then travel southeast this week
Hights H1, H2 and H3 are located between 40 and 45S and by mid-week
should be near 145W, 160E and 120E -consistent with a steady "wave 4"
around the planet.
The trough between Highs 2 and 3 is expected to cross NZ on Thursday
with some brief rain and a one-day southerly.
The SAM index/AAO index is positive and its trend this week is to
remain positive, so the fronts and SW wind bursts are not expected to
get far north this week.
High H1 in Tasman Sea is expected this week to travel across NZ on
Wednesday and Thursday. Before this there is a weak cold front/SW
change on Monday and Tuesday, but this is expected to weaken.
Panama Gulf to Galapagos: Good NE winds for starters and to 5N then OK
easterly or light winds and a good tail current to Galapagos.
Scattered tropical showers.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
16 March 2025
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 16 March 2025
How goes our Modoki La Nina
Looking at the ocean...
Modoki is a Japanese word loosely translated to "similar, but
different" or in New Zealand slang "Yeah, nah". Professor Toshio
Yamagata and a colleague named the phenomenon while investigating the
causes of Japan's hot summer in 2004.
This occurs when the Sea surface temperature SST in the central
equatorial Pacific cools, while the SST in the western and eastern
parts warm.
This differs from the regular La Nina where the cool zone is in the
eastern equatorial Pacific near the Galapagos.
A recent time section of SST anomalies near the equator and across the
Pacific, shows the cool zone of this La Nina is edging towards the 180
longitude. See psl.noaa.gov/map/clim/sst.shtml
The ENSO trend is followed by forecasting the SST for region NINO 3.4,
with values less than 0.5 needed for a La Nina event..
The combo of forecasts as calculated by IRI shows that
The Dynamic average forecast (red) stays below the La Nina threshold
(neutral)
and the Static model average (green) stays just over the La Nina
threshold until December this year.
I suppose we are somewhere in between.
Looking at the atmosphere...
The SOI index over the past month has been positive but trending to
zero.
TROPICS
There are no named cyclones around at present
In the past week Category-1
. Cyclone Jude killed at least six people when it roared onto
Mozambique's northeastern coast with winds of up to 75 mph, causing
significant flooding and extensive damage.
. Cyclone Ivone churned the open waters of the central Indian Ocean.
At present the MJO is poised to bring a new boost of energy onto
northern Australia over next few weeks and then into the Pacific by
early April
As seen at
www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/forca.shtml
WEATHER ZONES
The wind accumulation shows that the windy signature around the lows
and convergence zones.
The South Pacific Convergence zone SPCZ and tropical convergence is
very active over northern Australia. There was an active convergence
zone over Fiji /Samoa last week and it has travelled south and can be
seen going SE in the wind and rain accumulation forecasts.
This week is looking relatively quiet in the South Pacific tropics.
LOWS and HIGHS
An active Low and Front labelled L1 south of Tahiti is expected to go
off to the SSE.
The HIGH H1 now east of the North Island and with a ridge over
northern NZ, is expected to move off to the SE.
The Low labelled L2 east of Tasmania and its associated front is
expected to travel over NZ on Monday/Tuesday followed by a southerly
flow on Wednesday.
HIGH H2 now in Australian Bight is expected to follow L2 and cross NZ
on Thursday and Friday.
L3 is expected to travel east so that associated front reaches NZ on
Sat/Sunday.
In Gulf of Panama: Useful NE winds for starters but they may be over
20kt between Tuesday and Saturday.
From Panama to Galapagos.. SW swells 1 to 2m. Tail currents and mostly
a tail wind.
May be showery between 4 and 1N
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 16 March 2025
How goes our Modoki La Nina
Looking at the ocean...
Modoki is a Japanese word loosely translated to "similar, but
different" or in New Zealand slang "Yeah, nah". Professor Toshio
Yamagata and a colleague named the phenomenon while investigating the
causes of Japan's hot summer in 2004.
This occurs when the Sea surface temperature SST in the central
equatorial Pacific cools, while the SST in the western and eastern
parts warm.
This differs from the regular La Nina where the cool zone is in the
eastern equatorial Pacific near the Galapagos.
A recent time section of SST anomalies near the equator and across the
Pacific, shows the cool zone of this La Nina is edging towards the 180
longitude. See psl.noaa.gov/map/clim/sst.shtml
The ENSO trend is followed by forecasting the SST for region NINO 3.4,
with values less than 0.5 needed for a La Nina event..
The combo of forecasts as calculated by IRI shows that
The Dynamic average forecast (red) stays below the La Nina threshold
(neutral)
and the Static model average (green) stays just over the La Nina
threshold until December this year.
I suppose we are somewhere in between.
Looking at the atmosphere...
The SOI index over the past month has been positive but trending to
zero.
TROPICS
There are no named cyclones around at present
In the past week Category-1
. Cyclone Jude killed at least six people when it roared onto
Mozambique's northeastern coast with winds of up to 75 mph, causing
significant flooding and extensive damage.
. Cyclone Ivone churned the open waters of the central Indian Ocean.
At present the MJO is poised to bring a new boost of energy onto
northern Australia over next few weeks and then into the Pacific by
early April
As seen at
www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/forca.shtml
WEATHER ZONES
The wind accumulation shows that the windy signature around the lows
and convergence zones.
The South Pacific Convergence zone SPCZ and tropical convergence is
very active over northern Australia. There was an active convergence
zone over Fiji /Samoa last week and it has travelled south and can be
seen going SE in the wind and rain accumulation forecasts.
This week is looking relatively quiet in the South Pacific tropics.
LOWS and HIGHS
An active Low and Front labelled L1 south of Tahiti is expected to go
off to the SSE.
The HIGH H1 now east of the North Island and with a ridge over
northern NZ, is expected to move off to the SE.
The Low labelled L2 east of Tasmania and its associated front is
expected to travel over NZ on Monday/Tuesday followed by a southerly
flow on Wednesday.
HIGH H2 now in Australian Bight is expected to follow L2 and cross NZ
on Thursday and Friday.
L3 is expected to travel east so that associated front reaches NZ on
Sat/Sunday.
In Gulf of Panama: Useful NE winds for starters but they may be over
20kt between Tuesday and Saturday.
From Panama to Galapagos.. SW swells 1 to 2m. Tail currents and mostly
a tail wind.
May be showery between 4 and 1N
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
09 March 2025
Bobgram 9 March
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 9 March 2025
The March of the Sun in March
During March the latitude of the overhead sun (also known as the sun's
declination) changes from 10S to 5N. On the 21st it is over the
equator, and we call that event the equinox (10:01pm, Tuesday 20 March
NZDT).
When the overhead sun is between 10 and 5S in early March it often is
associated with the formation of a convergence zone located SW of
Galapagos. This convergence zone mimics the intensity and mirrors the
position of the Intertropical convergence zone:
This year it has produced a strong east going surface current around
the Galapagos:
This poses challenges to anyone attempting the Panama to Galapagos
voyage over the next few weeks
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/
GARANCE got to Cat 3 near the island of Réunion killing at least 5
people.
HONDE left at least three people dead and numerous buildings wrecked
in southern Madagascar. •
ALFRED brought a storm surge and heavy rain to Brisbane, killing at
least one person.
We can see how the track of cyclone stutters by watching ALFRED
approach Brisbane…
Last Tuesday/Wednesday what date/place would you have picked for
landfall, and how wrong would you have been?
JUDE is skirting around Madagascar
IVONE is over open sea in mid-south Indian Ocean.
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 The SPCZ active over
Vanuatu and Fiji. Alos there is another active convergence zone over
Samoa with flood warning.
And there is that "mirror convergence zone" at 5S to SW of Galapagos.
heavy rain from Tonga to Niue and with ALFRED.
Wind accumulation this week from Windy.com
The wind/rain accumulation shows trails of wind and rain mapped out by
L1
LOWS and HIGHS
Low L1 is expected to form (from under an upper cut off) to the NE of
northland on Monday and then travel to SE
A cold front /trough is expected to cross NZ on Monday/Tuesday
followed by a southerly flow. In this cold air a Low is expected to
form neat Chatham Island by late Thursday and then move off to the
east.
HIGH H1 south of Tasmania on Monday is expected to be diverted so that
is travels slowly north across the Tasman Sea this week. It should
push a ridge over southern and central NZ on Thursday and then weaken
into a ridge over Northland by end o week.
ALFRED is moving slowly south and MIGHT go inland late in the week
near Brisbane.
HIGH H1 now over North Island is moving off to the ESE.
This allows an active cold front to travel NE over NZ on Monday and
Tuesday and then form a Low L2 near Chathams on Wednesday with a
strong SE flow over NZ.
That should be followed by H2 now in Australian Bight and travelling
east across South Tasman mid-week then onto Northland for the weekend.
Low L2 in Australian Bight is expected to travel SE. Associated FRONT
is expected to travel east and cross NZ on Friday and Saturday
followed by a westerly with some strong winds.
HIGH H2 in Aussies bight is expected to be diverted to north of Hobart
and then northward to merge with H1.
Gulf of Panama: A useful NE flow for starters
Galapagos: There is a "mirror" CONVERGENCE ZONE with squalls a about
and mainly to SW of the group. Strong East to SE flowing surface
current around the group 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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 9 March 2025
The March of the Sun in March
During March the latitude of the overhead sun (also known as the sun's
declination) changes from 10S to 5N. On the 21st it is over the
equator, and we call that event the equinox (10:01pm, Tuesday 20 March
NZDT).
When the overhead sun is between 10 and 5S in early March it often is
associated with the formation of a convergence zone located SW of
Galapagos. This convergence zone mimics the intensity and mirrors the
position of the Intertropical convergence zone:
This year it has produced a strong east going surface current around
the Galapagos:
This poses challenges to anyone attempting the Panama to Galapagos
voyage over the next few weeks
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/
GARANCE got to Cat 3 near the island of Réunion killing at least 5
people.
HONDE left at least three people dead and numerous buildings wrecked
in southern Madagascar. •
ALFRED brought a storm surge and heavy rain to Brisbane, killing at
least one person.
We can see how the track of cyclone stutters by watching ALFRED
approach Brisbane…
Last Tuesday/Wednesday what date/place would you have picked for
landfall, and how wrong would you have been?
JUDE is skirting around Madagascar
IVONE is over open sea in mid-south Indian Ocean.
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 The SPCZ active over
Vanuatu and Fiji. Alos there is another active convergence zone over
Samoa with flood warning.
And there is that "mirror convergence zone" at 5S to SW of Galapagos.
heavy rain from Tonga to Niue and with ALFRED.
Wind accumulation this week from Windy.com
The wind/rain accumulation shows trails of wind and rain mapped out by
L1
LOWS and HIGHS
Low L1 is expected to form (from under an upper cut off) to the NE of
northland on Monday and then travel to SE
A cold front /trough is expected to cross NZ on Monday/Tuesday
followed by a southerly flow. In this cold air a Low is expected to
form neat Chatham Island by late Thursday and then move off to the
east.
HIGH H1 south of Tasmania on Monday is expected to be diverted so that
is travels slowly north across the Tasman Sea this week. It should
push a ridge over southern and central NZ on Thursday and then weaken
into a ridge over Northland by end o week.
ALFRED is moving slowly south and MIGHT go inland late in the week
near Brisbane.
HIGH H1 now over North Island is moving off to the ESE.
This allows an active cold front to travel NE over NZ on Monday and
Tuesday and then form a Low L2 near Chathams on Wednesday with a
strong SE flow over NZ.
That should be followed by H2 now in Australian Bight and travelling
east across South Tasman mid-week then onto Northland for the weekend.
Low L2 in Australian Bight is expected to travel SE. Associated FRONT
is expected to travel east and cross NZ on Friday and Saturday
followed by a westerly with some strong winds.
HIGH H2 in Aussies bight is expected to be diverted to north of Hobart
and then northward to merge with H1.
Gulf of Panama: A useful NE flow for starters
Galapagos: There is a "mirror" CONVERGENCE ZONE with squalls a about
and mainly to SW of the group. Strong East to SE flowing surface
current around the group 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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
02 March 2025
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 2 March 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/R1DQQPwkNYE
During February the climate modellers agreed the Pacific is in ENSO
neutral territory. The MJO travelled across the South Pacific during
the month activating the South Pacific Convergence zone and forming a
series of 7 tropical lows with 3 of them becoming cyclones in the last
week.
The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern, after a troughy January.
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 fading blue tongue along the central Pacific shows we are in ENSO
neutral territory.
Average isobars for past month (below)
From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
The Aleutian low and Greenland low have deepened.
The subtropical ridge in the Southern hemisphere has recovered after
its December extreme.
Pressure anomalies for past month (below)
The anomaly pressure pattern highlights these differences.
The 1015 isobar has expanded to cover NZ.
Ridge axis seems to have moved north of Tasmania.
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/
Cyclone RAE caused some crop damage in Fiji.
Cyclone SERU went over mainly open water between Vanuatu and Fiji.
ALFRED is a slow mover currently going south and MIGHT go inland near
Brisbane mid-week.
Cyclone BIANCA formed off northwestern Australia. Cyclone Garance
started near Réunion as Cyclone Honde threatened southern Madagascar.
WEATHER ZONES
Rain accumulation this week from Windy.com shows heavy rain from Tonga
to Niue and with ALFRED.
Wind accumulation this week from Windy.com
The wind accumulation shows trails of wind mapped out by ALFRED and L1
LOWS and HIGHS
Low L1 now near Fiji is the remains of SERU and is moving slowly east
.
ALFRED is moving slowly south and MIGHT go inland late in the week
near Brisbane.
HIGH H1 now over North Island is moving off to the ESE.
This allows an active cold front to travel NE over NZ on Monday and
Tuesday and then form a Low L2 near Chathams on Wednesday with a
strong SE flow over NZ.
That should be followed by H2 now in Australian Bight and travelling
east across South Tasman mid-week then onto NZ for the weekend.
Low L3 should form near Bass Strait on Wednesday, followed another
HIGH H3.
Low l4 should remain slow-moving over inland Australia, but the
monsoonal trough is rather dry this week.
Gulf of Panama: A useful NE flow for starters
Galapagos: A low has formed to the SW and there is a CONVERGENCE ZONE
with squalls over the group and another between 6 and 9S from 95W to
106W
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 2 March 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/R1DQQPwkNYE
During February the climate modellers agreed the Pacific is in ENSO
neutral territory. The MJO travelled across the South Pacific during
the month activating the South Pacific Convergence zone and forming a
series of 7 tropical lows with 3 of them becoming cyclones in the last
week.
The 500hPa heights and anomalies shows last month's typical ridge
/trough pattern, after a troughy January.
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 fading blue tongue along the central Pacific shows we are in ENSO
neutral territory.
Average isobars for past month (below)
From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
The Aleutian low and Greenland low have deepened.
The subtropical ridge in the Southern hemisphere has recovered after
its December extreme.
Pressure anomalies for past month (below)
The anomaly pressure pattern highlights these differences.
The 1015 isobar has expanded to cover NZ.
Ridge axis seems to have moved north of Tasmania.
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/
Cyclone RAE caused some crop damage in Fiji.
Cyclone SERU went over mainly open water between Vanuatu and Fiji.
ALFRED is a slow mover currently going south and MIGHT go inland near
Brisbane mid-week.
Cyclone BIANCA formed off northwestern Australia. Cyclone Garance
started near Réunion as Cyclone Honde threatened southern Madagascar.
WEATHER ZONES
Rain accumulation this week from Windy.com shows heavy rain from Tonga
to Niue and with ALFRED.
Wind accumulation this week from Windy.com
The wind accumulation shows trails of wind mapped out by ALFRED and L1
LOWS and HIGHS
Low L1 now near Fiji is the remains of SERU and is moving slowly east
.
ALFRED is moving slowly south and MIGHT go inland late in the week
near Brisbane.
HIGH H1 now over North Island is moving off to the ESE.
This allows an active cold front to travel NE over NZ on Monday and
Tuesday and then form a Low L2 near Chathams on Wednesday with a
strong SE flow over NZ.
That should be followed by H2 now in Australian Bight and travelling
east across South Tasman mid-week then onto NZ for the weekend.
Low L3 should form near Bass Strait on Wednesday, followed another
HIGH H3.
Low l4 should remain slow-moving over inland Australia, but the
monsoonal trough is rather dry this week.
Gulf of Panama: A useful NE flow for starters
Galapagos: A low has formed to the SW and there is a CONVERGENCE ZONE
with squalls over the group and another between 6 and 9S from 95W to
106W
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
23 February 2025
Bobgram 23 Feb
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 23 February2025
Sea Ice is now at its lowest on record in the Arctic and also near a
record low in the Antarctic.
See
nsidc.org/sea-ice-today/sea-ice-tools/charctic-interactive-sea-ice-gra
ph
TROPICS
Cyclone Zelia roared ashore as a Category-4 storm just east of Port
Hedland on northwestern Australia's Pilbara coast but failed to
inflict significant damage in the remote sparsely populated region.
Tropical depression Number 18 is in the Coral Sea, TD19 is near Niue
and TD20 is in the South Indian Ocean.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ with
heavy rain especially in Coral Sea from TD18 and near Southern
Tonga/Niue from TD19.
Wind accumulation this week from Windy.com
The wind accumulation gives a good indication of the possible path to
be taken by TD18 and the max winds associated with TD19. That green
zone from Coffs to Bay of Islands shows OK winds for sailing mid
Tasman this week. Light winds this week for Vanuatu
LOWS and HIGHS
Tropical Depression 18 in Coral Sea is expected to move slowly south
this week.
Tropical depression 19 is expected to travel slowly southeast
affecting southern Tong and Niue.
Another tropical Low L1 is expected to travel southeast and remain
south of Tahiti
A trough is crossing South Island on Monday and Tuesday then fading
over North Island on Wednesday as HIGH H1 travels east from Aussie
Bight to Tasman Sea. Later in the week H1 travels across southern NZ.
Panama gulf---- some useful northerly winds this week.
Galapagos: An unusual LOW is sitting to SW of Galapagos maintaining
a west to SW flow over the group along with a east-going current over
2kt at 1degree South latitude.. Be AWARE.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 23 February2025
Sea Ice is now at its lowest on record in the Arctic and also near a
record low in the Antarctic.
See
nsidc.org/sea-ice-today/sea-ice-tools/charctic-interactive-sea-ice-gra
ph
TROPICS
Cyclone Zelia roared ashore as a Category-4 storm just east of Port
Hedland on northwestern Australia's Pilbara coast but failed to
inflict significant damage in the remote sparsely populated region.
Tropical depression Number 18 is in the Coral Sea, TD19 is near Niue
and TD20 is in the South Indian Ocean.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ with
heavy rain especially in Coral Sea from TD18 and near Southern
Tonga/Niue from TD19.
Wind accumulation this week from Windy.com
The wind accumulation gives a good indication of the possible path to
be taken by TD18 and the max winds associated with TD19. That green
zone from Coffs to Bay of Islands shows OK winds for sailing mid
Tasman this week. Light winds this week for Vanuatu
LOWS and HIGHS
Tropical Depression 18 in Coral Sea is expected to move slowly south
this week.
Tropical depression 19 is expected to travel slowly southeast
affecting southern Tong and Niue.
Another tropical Low L1 is expected to travel southeast and remain
south of Tahiti
A trough is crossing South Island on Monday and Tuesday then fading
over North Island on Wednesday as HIGH H1 travels east from Aussie
Bight to Tasman Sea. Later in the week H1 travels across southern NZ.
Panama gulf---- some useful northerly winds this week.
Galapagos: An unusual LOW is sitting to SW of Galapagos maintaining
a west to SW flow over the group along with a east-going current over
2kt at 1degree South latitude.. Be AWARE.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
16 February 2025
Bobgram 16 Feb
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 16 February2025
Over 50 years of MJO
Fifty years ago, I started forecasting at Wellington Airport. In 1976 I started a 3-year period of forecasting at Nadi Airport and in 1979 I returned there another stint. During that summer in my spare time, I did some (unpublished) research investigating the extent and persistence of the South Pacific convergence zone SPCZ by compiling daily a cloudiness measure from the past 10 days of satellite imagery (thanks to then Director of Fiji Met Service Ram Krishna).
The story is that when we analysed the tropical weather maps in Fiji we would write the 24 hour pressure change next to each observation. Red for falling and blue for rising. We even had special red/blue pencils for this. I noticed that once a month or so we would go thru a period with a pulse of falling pressure travelling east across our map, followed by a pulse of blue, then a few weeks of relative quiet. In my stint starting 1979 I designed my cloudiness experiment to check the impact of this pulse on the SPCZ. You can see an animation of these maps here https://www.youtube.com/watch?v=dyXXHMA0_ro Very poor quality and jerky animation, and it didn't seem to show much, so I never bothered publishing anything. I wasn't aware of it at that time, but Madden and Julian had already published THEIR paper on this phenomenon
"Detection of a 40-50 day oscillation in the zonal wind in the Tropical Pacific."
https://journals.ametsoc.org/view/journals/atsc/28/5/1520-0469_1971_028_0702_doadoi_2_0_co_2.xml
Back in the early 70s, Roland A. Madden and Paul R. Julian were working for NCAR in Boulder Colorado, studying the QBO (Quasi -biennial Oscillation) n almost two-yearly switch of the zonal wind sin the stratosphere, and its impact on cyclone formation (one year more have increased risk, then be followed by a year with less risk). They wanted to find equatorial waves, so they examined 10 years of radiosonde (balloon flight data) from Canto Island. And found this 40-50day wave, now called the MJO.
The MJO is a pulse of extra convection that goes eastwards around the tropics, mainly noticeable from Indian Ocean, across the Indonesian to "top of Australia" region and the across the pacific. It is easy enough to track and thus worth following for it is indeed a forecasting tool.
In the following 50 years this mechanism has been studied by many, bringing with it many new terms to meteorology such mesoscale convective systems (MCSs), and convectively coupled equatorial waves (CCEWs). Papers have been written about how it triggers cyclones, extreme weather (even outside the tropics), and the onset of monsoons.
To use this forecasting tool in your own cruise planning, I recommend a trip to
https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foregfs.shtml
and to help you read the imagery, remember my mnemonic
BLUE is BUBBLY .................. YELLOW is MELLOW
The forecast shows an initial position and date, and then the trend for the following fortnight. Try to avoid the bubbly blue areas.
The website also shows recent data as a time /Longitude plot centred on the 180 meridian.
This graph shows the cyclic nature of the MJO and how it mainly manifests just from near 0 to near 180, and each pulse seems to have its own pace and intensity.
Anyway, today's data shows that the active phase of the MJO that has been affecting North Australia, and the South Pacific convergence zone is now slowly exiting, stage right. However, the activity near Tonga by midweek might deepen rapidly near southern Cooks late this week. Avoid.
This means that over the next few weeks of February there should be a period of relatively quiet weather with the SPCZ.
It also means that the next MJO active pulse is likely to move across the north end of Australia early in March and then into the Pacific around mid-March. Avoid.
TROPICS
Category-5 Cyclone Zelia took aim on a coastal stretch of northwestern Australia, halting mining and port operations in the remote region. * Cyclones Vince and Taliah lost force over the central Indian Ocean.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ with heavy rain especially from Rotuma to the Niua (N Tonga) to Niue to Southern Cooks associated with passing lows.
The wind accumulation shows wind zones associated with lows L2, L3 and L4.
Light winds this week for Vanuatu, after all that thundery weather there last week.
LOWS and HIGHS
The series of tropical lows L1, L2 and L3 are all expected to be steered slowly to south or southeast. L3 might grow to be a tropical cyclone affecting Southern Coos area late this week. Take note and check.
There is a Low approaching North Island on Monday from the north, and another deepening in Tasman Sea by Tuesday. These should cross NZ next few days and combine as L4 to south of South Island by late Wednesday, followed by a front and a southerly change Thu/Fri.
High H1 is expected to travel from Southern Bight to central Tasman Sea on Friday 21 Feb. Then this High H1 is expected to cross NZ on Sat/Sun 22/23 February.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world.
Compiled 16 February2025
Over 50 years of MJO
Fifty years ago, I started forecasting at Wellington Airport. In 1976 I started a 3-year period of forecasting at Nadi Airport and in 1979 I returned there another stint. During that summer in my spare time, I did some (unpublished) research investigating the extent and persistence of the South Pacific convergence zone SPCZ by compiling daily a cloudiness measure from the past 10 days of satellite imagery (thanks to then Director of Fiji Met Service Ram Krishna).
The story is that when we analysed the tropical weather maps in Fiji we would write the 24 hour pressure change next to each observation. Red for falling and blue for rising. We even had special red/blue pencils for this. I noticed that once a month or so we would go thru a period with a pulse of falling pressure travelling east across our map, followed by a pulse of blue, then a few weeks of relative quiet. In my stint starting 1979 I designed my cloudiness experiment to check the impact of this pulse on the SPCZ. You can see an animation of these maps here https://www.youtube.com/watch?v=dyXXHMA0_ro Very poor quality and jerky animation, and it didn't seem to show much, so I never bothered publishing anything. I wasn't aware of it at that time, but Madden and Julian had already published THEIR paper on this phenomenon
"Detection of a 40-50 day oscillation in the zonal wind in the Tropical Pacific."
https://journals.ametsoc.org/view/journals/atsc/28/5/1520-0469_1971_028_0702_doadoi_2_0_co_2.xml
Back in the early 70s, Roland A. Madden and Paul R. Julian were working for NCAR in Boulder Colorado, studying the QBO (Quasi -biennial Oscillation) n almost two-yearly switch of the zonal wind sin the stratosphere, and its impact on cyclone formation (one year more have increased risk, then be followed by a year with less risk). They wanted to find equatorial waves, so they examined 10 years of radiosonde (balloon flight data) from Canto Island. And found this 40-50day wave, now called the MJO.
The MJO is a pulse of extra convection that goes eastwards around the tropics, mainly noticeable from Indian Ocean, across the Indonesian to "top of Australia" region and the across the pacific. It is easy enough to track and thus worth following for it is indeed a forecasting tool.
In the following 50 years this mechanism has been studied by many, bringing with it many new terms to meteorology such mesoscale convective systems (MCSs), and convectively coupled equatorial waves (CCEWs). Papers have been written about how it triggers cyclones, extreme weather (even outside the tropics), and the onset of monsoons.
To use this forecasting tool in your own cruise planning, I recommend a trip to
https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/foregfs.shtml
and to help you read the imagery, remember my mnemonic
BLUE is BUBBLY .................. YELLOW is MELLOW
The forecast shows an initial position and date, and then the trend for the following fortnight. Try to avoid the bubbly blue areas.
The website also shows recent data as a time /Longitude plot centred on the 180 meridian.
This graph shows the cyclic nature of the MJO and how it mainly manifests just from near 0 to near 180, and each pulse seems to have its own pace and intensity.
Anyway, today's data shows that the active phase of the MJO that has been affecting North Australia, and the South Pacific convergence zone is now slowly exiting, stage right. However, the activity near Tonga by midweek might deepen rapidly near southern Cooks late this week. Avoid.
This means that over the next few weeks of February there should be a period of relatively quiet weather with the SPCZ.
It also means that the next MJO active pulse is likely to move across the north end of Australia early in March and then into the Pacific around mid-March. Avoid.
TROPICS
Category-5 Cyclone Zelia took aim on a coastal stretch of northwestern Australia, halting mining and port operations in the remote region. * Cyclones Vince and Taliah lost force over the central Indian Ocean.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ with heavy rain especially from Rotuma to the Niua (N Tonga) to Niue to Southern Cooks associated with passing lows.
The wind accumulation shows wind zones associated with lows L2, L3 and L4.
Light winds this week for Vanuatu, after all that thundery weather there last week.
LOWS and HIGHS
The series of tropical lows L1, L2 and L3 are all expected to be steered slowly to south or southeast. L3 might grow to be a tropical cyclone affecting Southern Coos area late this week. Take note and check.
There is a Low approaching North Island on Monday from the north, and another deepening in Tasman Sea by Tuesday. These should cross NZ next few days and combine as L4 to south of South Island by late Wednesday, followed by a front and a southerly change Thu/Fri.
High H1 is expected to travel from Southern Bight to central Tasman Sea on Friday 21 Feb. Then this High H1 is expected to cross NZ on Sat/Sun 22/23 February.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
02 February 2025
Bobgram 2 Feb 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 2 February 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/iXd4tg4toU8
During January the climate modellers agreed the Pacific is in ENSO neutral territory and have given up on the idea a La NINA trending in. The MJO built over Indian Ocean and has moved onto northern Australia., with several tropical systems now around Australia.
The 500hPa heights and anomalies shows last month's trough fading then a series of large HIGHs south and east of NZ for a few weeks in January
For much of the month a HIGH straddled southern and eastern NZ as seen here on 21Jan.
Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
show a fading blue tongue along the central Pacific so we are now in ENSO neutral territory.
Average isobars for past month (below)
From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
show that The Aleutian low has relaxed, and the Greenland low has deepened.
The subtropical ridge in the Southern hemisphere is still weak but has recovered a little from its December extreme.
The anomaly pressure pattern highlights these differences.
The 1010 trough-anomaly has sifted east off NZ.
The 1015 line south of Australia has shrunk.
TROPICS
There are no named storms around at present, but there are 4 tropical depressions being watched and a fifth in Gulf of Carpentaria too close (at present) to land to be able to spin-up however is bringing flooding rains to the eastern Qld coast. The MJO is active around Australia.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ and the heavy rain especially with the tropical low near New Caledonia and about eastern Qld coast.
The wind accumulation shows trails of wind mapped out by tropical lows L1 and L2.
LOWS and HIGHS
Low L1 now near Raoul Island is expected to deepen a lot as it travels southeast.
Tropical Low L2 near New Caledonia is also expected to deepen and bring heavy rain to Loyalty islands then move slowly southeast towards Minerva reef, so is mostly south of Fiji/Tonga.
Tropical Low L3 is expected to stay slow-moving over inland Australia, like a monsoonal low, feeding flooding rains onto Qld east coast.
High H1 in Tasman Sea is Quasi stationary. It may fade away on Thursday/Waitangi Day, as a brief passing front brings a southerly wind change to NZ East Coast, then H1 may reform.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are from the patterned world.
Compiled 2 February 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/iXd4tg4toU8
During January the climate modellers agreed the Pacific is in ENSO neutral territory and have given up on the idea a La NINA trending in. The MJO built over Indian Ocean and has moved onto northern Australia., with several tropical systems now around Australia.
The 500hPa heights and anomalies shows last month's trough fading then a series of large HIGHs south and east of NZ for a few weeks in January
For much of the month a HIGH straddled southern and eastern NZ as seen here on 21Jan.
Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
show a fading blue tongue along the central Pacific so we are now in ENSO neutral territory.
Average isobars for past month (below)
From http://www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
show that The Aleutian low has relaxed, and the Greenland low has deepened.
The subtropical ridge in the Southern hemisphere is still weak but has recovered a little from its December extreme.
The anomaly pressure pattern highlights these differences.
The 1010 trough-anomaly has sifted east off NZ.
The 1015 line south of Australia has shrunk.
TROPICS
There are no named storms around at present, but there are 4 tropical depressions being watched and a fifth in Gulf of Carpentaria too close (at present) to land to be able to spin-up however is bringing flooding rains to the eastern Qld coast. The MJO is active around Australia.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ and the heavy rain especially with the tropical low near New Caledonia and about eastern Qld coast.
The wind accumulation shows trails of wind mapped out by tropical lows L1 and L2.
LOWS and HIGHS
Low L1 now near Raoul Island is expected to deepen a lot as it travels southeast.
Tropical Low L2 near New Caledonia is also expected to deepen and bring heavy rain to Loyalty islands then move slowly southeast towards Minerva reef, so is mostly south of Fiji/Tonga.
Tropical Low L3 is expected to stay slow-moving over inland Australia, like a monsoonal low, feeding flooding rains onto Qld east coast.
High H1 in Tasman Sea is Quasi stationary. It may fade away on Thursday/Waitangi Day, as a brief passing front brings a southerly wind change to NZ East Coast, then H1 may reform.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
26 January 2025
Bob Blog 26 Jan 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 26 January 2025
New Zealand weather review 2024
Rainfall
Around the globe the average rainfall rate is just less than a metre
per year.
NOAA's Global Precipitation Climate Project have been watching this:
Roughly every fifth year is wetter, as it was in 2024.
The Southern Hemisphere is drier and has been showing a drying trend,
but bucked that in 2024.
The Australia BoM shows the regional forecast rain terciles for
February at http://www.bom.gov.au/climate/pacific/outlooks/
In this map some places between the Coral Sea and Tonga are expected
to have an over 80% chance of being above normal. And the shading is a
good proxy for the expected average position of the Thundery South
Pacific Convergence zone for the coming month.
Fingers of extra wetness spread from the Coral Sea to northern NZ.
TROPICS
The MJO is now in the Indian ocean and moving onto the NW end of
Australia.
There are currently no named cyclones anywhere
Last week Cyclone Sean brought torrential rains in northwestern
Australia but caused little damage in the region.
WEATHER ZONES
The wind accumulation shows that the wind builds up in areas such as
he Coral Sea and NW of New Caledonia, but not along the SPCZ (whose
position is shown in the rain accumulation).
So for the coming week they may be soe wind and some rain, but they
are NOT expected to combine.
A tropical low L4 is expected to form on the SPCZ in the New Caledonia
area from mid-week Avoid,
LOWS and HIGHS
LOW L1 is well south of Tahiti tonight and expected to travel off to
the Se
LOW L2 is crossing NZ tonight and expected to travel off to the
Southeast.
HIGH H1 is expected to cross NZ on Tuesday.
Low L3 and accompanying front is expected to travel across NZ
mid-week.
After that High H3 should move onto NZ, then to east of NZ this
weekend.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 26 January 2025
New Zealand weather review 2024
Rainfall
Around the globe the average rainfall rate is just less than a metre
per year.
NOAA's Global Precipitation Climate Project have been watching this:
Roughly every fifth year is wetter, as it was in 2024.
The Southern Hemisphere is drier and has been showing a drying trend,
but bucked that in 2024.
The Australia BoM shows the regional forecast rain terciles for
February at http://www.bom.gov.au/climate/pacific/outlooks/
In this map some places between the Coral Sea and Tonga are expected
to have an over 80% chance of being above normal. And the shading is a
good proxy for the expected average position of the Thundery South
Pacific Convergence zone for the coming month.
Fingers of extra wetness spread from the Coral Sea to northern NZ.
TROPICS
The MJO is now in the Indian ocean and moving onto the NW end of
Australia.
There are currently no named cyclones anywhere
Last week Cyclone Sean brought torrential rains in northwestern
Australia but caused little damage in the region.
WEATHER ZONES
The wind accumulation shows that the wind builds up in areas such as
he Coral Sea and NW of New Caledonia, but not along the SPCZ (whose
position is shown in the rain accumulation).
So for the coming week they may be soe wind and some rain, but they
are NOT expected to combine.
A tropical low L4 is expected to form on the SPCZ in the New Caledonia
area from mid-week Avoid,
LOWS and HIGHS
LOW L1 is well south of Tahiti tonight and expected to travel off to
the Se
LOW L2 is crossing NZ tonight and expected to travel off to the
Southeast.
HIGH H1 is expected to cross NZ on Tuesday.
Low L3 and accompanying front is expected to travel across NZ
mid-week.
After that High H3 should move onto NZ, then to east of NZ this
weekend.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
19 January 2025
Bobgram 19 Jan 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 19 January 2025
New Zealand weather review 2024
In a time-latitude plot of the air temperature measured over a
north-south slice of Aotearoa/ NZ as it travelled through 2024.
It clearly shows temperature is cooler further south and during
winter.
This time section makes a "bar-code" graph which reveals the annual
trend and the daily variation. It gives a rough indication of the
extremes and provides a visual image for quick comparison with any
another year to see seasonal variations. The land silhouette is
provided to help relate the latitude axis to your place.
Looking at a similar diagram for the barometric air pressure provides
a graph that combines all the daily weather maps into one image.
This produces a more random looking barcode. The yellow and red lines
correspond to passing HIGHS on the weather map, and the blues show the
LOWS or depressions/storms. Th "HIGH JULY" stands out (see
https://blog.metservice.com/node/1192)
There is a notable swing to blue low pressure that started from 20
December. This continued into January 2025.
The rain image is probably the most interesting as it highlights the
dry periods in Northland last February, April and late November to
early December
TROPICS
The MJO is now in the Indian ocean and moving onto the NW end of
Australia.
Tropical cyclone Sean is travelling out to sea from the Karratha
region.
WEATHER ZONES
TC Sean's forecast stands out in the wind and rain accumulation maps.
The South Pacific Convergence zone SPCZ is expected to have a routine
week and mainly be between Solomon Islands and Tokelau, north of
Samoa.
LOWS and HIGHS
The High which has been lingering well to southeast of Tahiti for past
ten days is expected to move off to Southeast this week.
The Low which has been lingering near Chatham Islands for past 10 days
is also expected to now move quickly off to the Southeast. This allows
the High that is currently around southern NZ to also move off to the
east following that Low/
A multi-centred complex low L1 in the Tasman Sea to NW o Auckland is
expected to travel southeast across Northland on Tuesday then weaken.
An active front is expected to reach Tasmania on Tuesday night and
then cross NZ on Thursday and Friday and weaken.
That Low is expected to be following by a High H2, and that front is
expected to be followed by a High H3 starting in the Aussie Bight.
These highs should combine in the Tasman Sea and then cross NZ on
Friday/Saturday.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 19 January 2025
New Zealand weather review 2024
In a time-latitude plot of the air temperature measured over a
north-south slice of Aotearoa/ NZ as it travelled through 2024.
It clearly shows temperature is cooler further south and during
winter.
This time section makes a "bar-code" graph which reveals the annual
trend and the daily variation. It gives a rough indication of the
extremes and provides a visual image for quick comparison with any
another year to see seasonal variations. The land silhouette is
provided to help relate the latitude axis to your place.
Looking at a similar diagram for the barometric air pressure provides
a graph that combines all the daily weather maps into one image.
This produces a more random looking barcode. The yellow and red lines
correspond to passing HIGHS on the weather map, and the blues show the
LOWS or depressions/storms. Th "HIGH JULY" stands out (see
https://blog.metservice.com/node/1192)
There is a notable swing to blue low pressure that started from 20
December. This continued into January 2025.
The rain image is probably the most interesting as it highlights the
dry periods in Northland last February, April and late November to
early December
TROPICS
The MJO is now in the Indian ocean and moving onto the NW end of
Australia.
Tropical cyclone Sean is travelling out to sea from the Karratha
region.
WEATHER ZONES
TC Sean's forecast stands out in the wind and rain accumulation maps.
The South Pacific Convergence zone SPCZ is expected to have a routine
week and mainly be between Solomon Islands and Tokelau, north of
Samoa.
LOWS and HIGHS
The High which has been lingering well to southeast of Tahiti for past
ten days is expected to move off to Southeast this week.
The Low which has been lingering near Chatham Islands for past 10 days
is also expected to now move quickly off to the Southeast. This allows
the High that is currently around southern NZ to also move off to the
east following that Low/
A multi-centred complex low L1 in the Tasman Sea to NW o Auckland is
expected to travel southeast across Northland on Tuesday then weaken.
An active front is expected to reach Tasmania on Tuesday night and
then cross NZ on Thursday and Friday and weaken.
That Low is expected to be following by a High H2, and that front is
expected to be followed by a High H3 starting in the Aussie Bight.
These highs should combine in the Tasman Sea and then cross NZ on
Friday/Saturday.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
12 January 2025
Bob Blog 12 Jan
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 12 January 2025
Is this a La Nina Modoki?
Modoki is a Japanese word loosely translated to "similar, but
different" or in New Zealand slang "Yeah, nah". Professor Toshio
Yamagata and a colleague named the phenomenon while investigating the
causes of Japan's hot summer in 2004.
This occurs when the Sea surface temperature SST in the central
equatorial Pacific coos, while the SST in the western and eastern
parts warm.
This differs from the regular La Nina where the cool zone is in the
eastern equatorial Pacific as shown here on the left.
A La Nina Modoki shifts the Jetstream that intercepts western north
America. This explains the drought over central California, a primary
factor in this week's wildfires.
A recent time section of SST anomalies near the equator and across the
Pacific,
For a deeper look t La Nina Modoki see
www.youtube.com/watch?v=VxIwP9V0pTs
TROPICS
The MJO is now in the Indian ocean. Tropical cyclone DIKELEDI is
skirting Madagascar.
In the Pacific PITA formed briefly on the South pacific Convergence
zone near Niue and is now weakening near the Southern Cooks.
WEATHER ZONES
The wind accumulation shows the windy signature of the Lows.
The South Pacific Convergence zone SPCZ is very active from Solomon
Islands to Samoa to Southern cooks
and expected to visit the Society Islands mid-week. Avoid
LOWS and HIGHS
For the next few days there is still a lot of wind around the
south-eastern sector of the now subtropical low L1, the remains of
cyclone PITA, south of the Southern Cooks.
The large deep Low southeast of Chatham Islands is expected to remain
in force until mid-week and then go southeast.
The High H1 in the Tasman Sea is expected to cross NZ on Tuesday and
Wednesday. These are good days for sailing south along NZ west coast
The Low L3 is expected to form east of Brisbane on Monday and then
slowly deepen and travel east to be near Norfolk Island by Thursday
and then to go to the south. Avoid.
Another Low L4 is expected to cross south of Tasmania on Wednesday and
then move off to the southeast.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 12 January 2025
Is this a La Nina Modoki?
Modoki is a Japanese word loosely translated to "similar, but
different" or in New Zealand slang "Yeah, nah". Professor Toshio
Yamagata and a colleague named the phenomenon while investigating the
causes of Japan's hot summer in 2004.
This occurs when the Sea surface temperature SST in the central
equatorial Pacific coos, while the SST in the western and eastern
parts warm.
This differs from the regular La Nina where the cool zone is in the
eastern equatorial Pacific as shown here on the left.
A La Nina Modoki shifts the Jetstream that intercepts western north
America. This explains the drought over central California, a primary
factor in this week's wildfires.
A recent time section of SST anomalies near the equator and across the
Pacific,
For a deeper look t La Nina Modoki see
www.youtube.com/watch?v=VxIwP9V0pTs
TROPICS
The MJO is now in the Indian ocean. Tropical cyclone DIKELEDI is
skirting Madagascar.
In the Pacific PITA formed briefly on the South pacific Convergence
zone near Niue and is now weakening near the Southern Cooks.
WEATHER ZONES
The wind accumulation shows the windy signature of the Lows.
The South Pacific Convergence zone SPCZ is very active from Solomon
Islands to Samoa to Southern cooks
and expected to visit the Society Islands mid-week. Avoid
LOWS and HIGHS
For the next few days there is still a lot of wind around the
south-eastern sector of the now subtropical low L1, the remains of
cyclone PITA, south of the Southern Cooks.
The large deep Low southeast of Chatham Islands is expected to remain
in force until mid-week and then go southeast.
The High H1 in the Tasman Sea is expected to cross NZ on Tuesday and
Wednesday. These are good days for sailing south along NZ west coast
The Low L3 is expected to form east of Brisbane on Monday and then
slowly deepen and travel east to be near Norfolk Island by Thursday
and then to go to the south. Avoid.
Another Low L4 is expected to cross south of Tasmania on Wednesday and
then move off to the southeast.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
05 January 2025
Bobgram 5 Jan 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 5 January 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/VwQ10R1FMR0
December had an MJO period over North Australia and into the South
Pacific between 20 and 30 December. An unnamed and minimal tropical
storm skirted Australia's remote Cocos Islands territory, in the
eastern Indian Ocean. And some small tropical depressions formed
between Vanuatu and northern Tonga, drenching Fiji.
Next MJO may be in late January.
The 500hPa heights and anomalies show interesting upper troughs
spreading from the north onto NZ during that MJO.
This led to a series of Lows mainly east of NZ, for example on
Christmas Day
Sea Surface temperature anomalies as at
psl.noaa.gov/map/clim/sst.shtml
show a fading blue tongue along the central Pacific shows that the
trend to a La Nina is stalling.
Average isobars for past month
show that the Aleutian low has deepened.
The subtropical ridge in the Southern hemisphere has weakened, and
around NZ has been replaced by a trough.
Pressure anomalies for past month highlights these differences.
The 1020 over New Zealand has dropped to between 1000 and 1010hPa.
It snowed on the Dessert Road today, gulp.
TROPICS
There are no named storms around at present.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ over
Solomon Islands to Samoa/northern Tonga.
The wind accumulation shows that the Low east of NZ, L1 is surrounded
by lots of wind.
LOWS and HIGHS
The Low L1 east of NZ is expected to become a slow-moving complex.
Avoid.
A Low L2 is expected to form on the SPCZ near norther Tonga and go SE
towards Southern Cooks
then south and join the L1 complex. Avoid
High H1 now in Australian Bight is expected to move around south side
of Tasmania on Tuesday
then around south side of NZ late in the week and expand over whole of
at end of the week to early next week.
Low L3 over inland Australia is associated with a heatwave and
expected to move slowly to Victoria by end of the week.
It may deepen in Tasman Sea 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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Disclaimer: Weather is a mix of pattern and chaos; these ideas are
from the patterned world.
Compiled 5 January 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/VwQ10R1FMR0
December had an MJO period over North Australia and into the South
Pacific between 20 and 30 December. An unnamed and minimal tropical
storm skirted Australia's remote Cocos Islands territory, in the
eastern Indian Ocean. And some small tropical depressions formed
between Vanuatu and northern Tonga, drenching Fiji.
Next MJO may be in late January.
The 500hPa heights and anomalies show interesting upper troughs
spreading from the north onto NZ during that MJO.
This led to a series of Lows mainly east of NZ, for example on
Christmas Day
Sea Surface temperature anomalies as at
psl.noaa.gov/map/clim/sst.shtml
show a fading blue tongue along the central Pacific shows that the
trend to a La Nina is stalling.
Average isobars for past month
show that the Aleutian low has deepened.
The subtropical ridge in the Southern hemisphere has weakened, and
around NZ has been replaced by a trough.
Pressure anomalies for past month highlights these differences.
The 1020 over New Zealand has dropped to between 1000 and 1010hPa.
It snowed on the Dessert Road today, gulp.
TROPICS
There are no named storms around at present.
WEATHER ZONES
Rain accumulation this week from Windy.com shows an intense SPCZ over
Solomon Islands to Samoa/northern Tonga.
The wind accumulation shows that the Low east of NZ, L1 is surrounded
by lots of wind.
LOWS and HIGHS
The Low L1 east of NZ is expected to become a slow-moving complex.
Avoid.
A Low L2 is expected to form on the SPCZ near norther Tonga and go SE
towards Southern Cooks
then south and join the L1 complex. Avoid
High H1 now in Australian Bight is expected to move around south side
of Tasmania on Tuesday
then around south side of NZ late in the week and expand over whole of
at end of the week to early next week.
Low L3 over inland Australia is associated with a heatwave and
expected to move slowly to Victoria by end of the week.
It may deepen in Tasman Sea 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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Subscribe to:
Posts (Atom)