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 Sunday25 August 2024
ATLANTICCYCLONE SEASON - why so quiet?
At the start of this year's cyclone season a few months a go the
initial outlook was for a busy and active season with between 17 and
25 named storms. Now we are approaching the half-way mark and there
have only been 5 named storms. What gives?
Well, BERYL (June 28-July 11) had lots of cyclone energy, so the
accumulated cyclone energy graph shows we are having an active season.
Accumulated cyclone energy (ACE) this season has been historically
high despite the perceived slow start to the season. Thanks to (Kim
Wood/University of Arizona at kouya.has.arizona.edu/tropics/index.html
Also the current pause in Atlantic cyclone activity may be related to
what is called an ATLANTIC NINA or cooling of the seas surface due to
a zone of stronger trade winds triggering marked upwelling as show
near 1 in the Sea surface anomaly map
The cooling in the Eastern Equatorial Pacific indicates a trend
towards LA NINA. We are NOT there yet, and the pace of cooling has
recently stalled.
Maybe in September this cooling pace will resume, also there may be a
flurry of North Atlantic cyclones.
TROPICS
. A near miss on eastern Japan by Category-4 Typhoon Ampil spared the
region notable damage. . After making a direct hit on Bermuda with
Category-2 force, Hurricane Ernesto brushed Newfoundland and was
predicted to bring heavy rain and high winds to Ireland, the U.K. and
parts of Western Europe.
. Gilma reached hurricane force, moving westward over the Pacific
Ocean.
WEATHER ZONES
The South Pacific Convergence zone is increasing in width and
intensity and stretches from Solomon Islands to Tokelau /Samoa.
Another convergence zone over Fiji Sunday night a d Tonga on Monday os
associated with a Low L1 which should form south of Tonga on Monday
and then trave ESE during the week as a weak trough. The strong winds
and large swells which bothered Fresch Polynesia last week due to a
squash zone are expected to relax enough to allow travel westwards
from local TUESDAY. t
HIGHS and LOWS
This coming week should see a steady procession of HIGHs and LOWs
eastwards in the mid-latitudes.
HIGH H1 gave French Polynesia a squash zone for the last few days and
is now moving off to the south relaxing the pressure gradient.
HIGH H2 is expected to travel east along 25S, into north Tasman Sea
Further south a disturbed westerly flow should bring passing fronts to
Aotearoa NZ especially on Tuesday and Thursday/Friday then Sunday and
again on following Tuesday. Avoid arriving those days.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check
metbob.com to see what I offer.
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
25 August 2024
18 August 2024
Bobgram 18 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 Sunday18 August 2024
POLAR VOTEX
The southern polar vortex is a ring of wind swirling over Antarctica
and this has been wobbling more than normal recently.
Our polar vortex is rather untidy, with a sheath of cold air extending
north into the Tasman Sea/South Island area, and another extending as
far north as 30S near Southern Cooks.
In July there was a SSW or sudden stratospheric warming event. This
was caused by a large-scale atmospheric wave, called a Rossby wave,
that was pushed up from below until it "broke" on top of the polar
vortex, causing the downwelling of a layer of air and thus a warming
of a large zone in the stratosphere. A SSW is a rare event -- last
three known events occurred in 2002,2010 and 2019. They disrupt the
polar vortex and encourage outbreaks .
SAM the Southern Annular Mode is a parameter we use to measure the
strength of the polar vortex. When SAM is negative the Polar vortex is
weak and allows polar outbreaks. I have access to AAO (The AntArctic
Oscillation) and use this as a proxy for SAM and it shows a long weak
period of the Polar vortex during July and August, but it is now near
normal and the forecast is for it to become positive in next few
weeks, retuning the Polar Vortex's health.
May be
TROPICS
Parts of northern Japan received record rainfall from Typhoon Maria. .
Maria was followed by Typhoon Ampil, which skirted the coast near
Tokyo and is now moving off to the northeast. . Tropical Storm
SonTinh dissipated near Japan's northernmost islands. . The Windward
Islands and Puerto Rico were raked and flooded by strengthening
Hurricane ERNESTO
WEATHER ZONES
The South Pacific Convergence zone is increasing in width and
intensity and stretches from Solomon Islands to Tokelau to Suwarrow.
A weak passing trough is crossing New Caledonia tonight and Tonga on
local Tuesday then fading sway.
HIGHS and LOWS
This coming week should see a steady procession of HIGHs and LOWs
eastwards in the mid-latitudes. The trough associated with Low L1 is
travelling east across Aotearoa NZ tonight and Monday, followed by a
cold southerly outbreak on Tuesday.
HIGH H2 is expected to cross Aotearoa NZ on Wednesday followed by the
trough associated with L2 on Friday and Saturday.
During the weekend on 24/25 August a trough is expected to stall
between NZ and Fiji and deepen into Low which may affect voyages next
week. So be aware of that and update accordingly.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check
metbob.com to see what I offer.
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 Sunday18 August 2024
POLAR VOTEX
The southern polar vortex is a ring of wind swirling over Antarctica
and this has been wobbling more than normal recently.
Our polar vortex is rather untidy, with a sheath of cold air extending
north into the Tasman Sea/South Island area, and another extending as
far north as 30S near Southern Cooks.
In July there was a SSW or sudden stratospheric warming event. This
was caused by a large-scale atmospheric wave, called a Rossby wave,
that was pushed up from below until it "broke" on top of the polar
vortex, causing the downwelling of a layer of air and thus a warming
of a large zone in the stratosphere. A SSW is a rare event -- last
three known events occurred in 2002,2010 and 2019. They disrupt the
polar vortex and encourage outbreaks .
SAM the Southern Annular Mode is a parameter we use to measure the
strength of the polar vortex. When SAM is negative the Polar vortex is
weak and allows polar outbreaks. I have access to AAO (The AntArctic
Oscillation) and use this as a proxy for SAM and it shows a long weak
period of the Polar vortex during July and August, but it is now near
normal and the forecast is for it to become positive in next few
weeks, retuning the Polar Vortex's health.
May be
TROPICS
Parts of northern Japan received record rainfall from Typhoon Maria. .
Maria was followed by Typhoon Ampil, which skirted the coast near
Tokyo and is now moving off to the northeast. . Tropical Storm
SonTinh dissipated near Japan's northernmost islands. . The Windward
Islands and Puerto Rico were raked and flooded by strengthening
Hurricane ERNESTO
WEATHER ZONES
The South Pacific Convergence zone is increasing in width and
intensity and stretches from Solomon Islands to Tokelau to Suwarrow.
A weak passing trough is crossing New Caledonia tonight and Tonga on
local Tuesday then fading sway.
HIGHS and LOWS
This coming week should see a steady procession of HIGHs and LOWs
eastwards in the mid-latitudes. The trough associated with Low L1 is
travelling east across Aotearoa NZ tonight and Monday, followed by a
cold southerly outbreak on Tuesday.
HIGH H2 is expected to cross Aotearoa NZ on Wednesday followed by the
trough associated with L2 on Friday and Saturday.
During the weekend on 24/25 August a trough is expected to stall
between NZ and Fiji and deepen into Low which may affect voyages next
week. So be aware of that and update accordingly.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check
metbob.com to see what I offer.
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
11 August 2024
Bobgram 11 August
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 Sunday 11 August 2024
The AMAZON as a measure of Climate change
A recent NATURE article
www.nature.com/articles/s41598-024-58782-5#citeas
offers data that can, visually anyway, show what maybe the impact of
global climate change over the past century and its increasing impact
over the past 20 years.
Showing he height of the Amazon level has been measured at MANUS near
the centre of the Amazon for over100 years.
This shows the annual cycle and also a possible sunspot cycle.
I've added the red and green trend arrows to the article's data graph
shown in my illustrated edition.
The article concentrates on the increasing annual cycle and links the
record breaking drought on 23 Oct 2023 to the EL NINO then rampant and
also to the generally warmer than normal Pacific Ocean.
A REGIONAL DROUGHT is affecting the New Zealand Hydro lakes
NIWA (NZ) say that during the month of July 2024 "mean sea level air
pressure (MSLP) was higher than normal over and to the south of
Aotearoa New Zealand. This was associated with more south-easterly
winds than normal. A large and slow-moving high pressure system was
present over New Zealand for much of July, leading to an extended
period of fine and settled weather, and regular heavy frosts for
inland areas. The strength of the high pressure peaked on 10 July,
when Ranfurly registered a MSLP of 1046.5 hPa - this is mainland New
Zealand's highest MSLP measurement on record."
This drop in input into the hydro lakes was enough to almost triple
the spot price of electricity in the past month.
The Higher pressures in July around Aotearoa New Zealand were just a
regional impact .
TROPICS
When DEBBY made landfall over Florida, it brought some unprecedented
flooding. . Then there were four named storms churning the Pacific at
the same time off Mexico and this is the highest number for the region
in 50 years. Only Carlotta lived long enough to travel significantly
westward toward Hawaii.
Tonight MARIA is making landfall over northern Japan, and there are 3
tropical depressions with one following Maria, one in the NE Pacific
and one in the Atlantic.
WEATHER ZONES
The South Pacific Convergence zone is increasing in width and
intensity and stretches from Solomon Islands to Tokelau to Suwarrow. A
passing trough is expected over Southern Cooks late in the week..
HIGHS and LOWS
Low L1 is travelling northeast on Monday to east of NZ bringing a
showery southerly flow.
From Tuesday to Thursday HIGH H1 should travel NE across northern NZ.,
a good time to arrive. Then this HIGH should travel east along 30S
with a small squash zone of stronger easterly winds crossing Niue ,
for example, on local Thursday/Friday.
Low L2 should start forming in Coral Sea from Tuesday and deepen off
Brisbane from Thursday then travel southeast across NZ on Saturday
preceded by strong NE winds, accompanied by heavy rain and followed by
southerly winds. AVOID arriving in NZ as this FRONT passes.
The models are in disagreement for next week's Tasman Sea pattern, so
seek updates for that.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check
metbob.com to see what I offer.
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 Sunday 11 August 2024
The AMAZON as a measure of Climate change
A recent NATURE article
www.nature.com/articles/s41598-024-58782-5#citeas
offers data that can, visually anyway, show what maybe the impact of
global climate change over the past century and its increasing impact
over the past 20 years.
Showing he height of the Amazon level has been measured at MANUS near
the centre of the Amazon for over100 years.
This shows the annual cycle and also a possible sunspot cycle.
I've added the red and green trend arrows to the article's data graph
shown in my illustrated edition.
The article concentrates on the increasing annual cycle and links the
record breaking drought on 23 Oct 2023 to the EL NINO then rampant and
also to the generally warmer than normal Pacific Ocean.
A REGIONAL DROUGHT is affecting the New Zealand Hydro lakes
NIWA (NZ) say that during the month of July 2024 "mean sea level air
pressure (MSLP) was higher than normal over and to the south of
Aotearoa New Zealand. This was associated with more south-easterly
winds than normal. A large and slow-moving high pressure system was
present over New Zealand for much of July, leading to an extended
period of fine and settled weather, and regular heavy frosts for
inland areas. The strength of the high pressure peaked on 10 July,
when Ranfurly registered a MSLP of 1046.5 hPa - this is mainland New
Zealand's highest MSLP measurement on record."
This drop in input into the hydro lakes was enough to almost triple
the spot price of electricity in the past month.
The Higher pressures in July around Aotearoa New Zealand were just a
regional impact .
TROPICS
When DEBBY made landfall over Florida, it brought some unprecedented
flooding. . Then there were four named storms churning the Pacific at
the same time off Mexico and this is the highest number for the region
in 50 years. Only Carlotta lived long enough to travel significantly
westward toward Hawaii.
Tonight MARIA is making landfall over northern Japan, and there are 3
tropical depressions with one following Maria, one in the NE Pacific
and one in the Atlantic.
WEATHER ZONES
The South Pacific Convergence zone is increasing in width and
intensity and stretches from Solomon Islands to Tokelau to Suwarrow. A
passing trough is expected over Southern Cooks late in the week..
HIGHS and LOWS
Low L1 is travelling northeast on Monday to east of NZ bringing a
showery southerly flow.
From Tuesday to Thursday HIGH H1 should travel NE across northern NZ.,
a good time to arrive. Then this HIGH should travel east along 30S
with a small squash zone of stronger easterly winds crossing Niue ,
for example, on local Thursday/Friday.
Low L2 should start forming in Coral Sea from Tuesday and deepen off
Brisbane from Thursday then travel southeast across NZ on Saturday
preceded by strong NE winds, accompanied by heavy rain and followed by
southerly winds. AVOID arriving in NZ as this FRONT passes.
The models are in disagreement for next week's Tasman Sea pattern, so
seek updates for that.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check
metbob.com to see what I offer.
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
04 August 2024
Bobgram 4 August
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 Sunday 4 August 2024
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/alCjq_vMeqM
An interesting period of weather occurred when a LOW was blocked in the Tasman Sea from 14 to 24 July under a closed low aloft. As in June there was a dose of rapid cyclogenesis between 19 and 20 July.
The tropics in the South Pacific were quiet.
Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The Kuroshio current has spread out into the north Pacific. The equatorial Atlantic remains warmer than normal. The cool seas of an El Nino are spreading westwards from Galapagos to the dateline along the equator. A buildup of cold water - melted ice is showing around the Aleutians.
Average isobars for past month as at www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
During July the Monsoon spread east across Asia and the subtropical ridge in northern hemisphere intensifies.
Pressure anomalies for past month (below)
The anomaly pressure pattern for July shows a relaxing away of the negative anomalies that were over North America and Australia. South America has built up large positive anomalies.
Around Suth Pacific : Not much change, but the low anomalies in the Tasman have faded.
TROPICS
Typhoon Gaemi weakened to a tropical storm as it made landfall on South China's Fujian coast. Even as a weakened storm, Gaemi's remnants had enough power to kill 22 people in disastrous flooding and mudslides across a wide area of China and parts of North Korea. In total, Typhoon Gaemi was responsible for at least 77 deaths over a two-week period. * Tropical Storm Bud formed briefly
Tonight we have DANIEL and CARLOTTA in the NE Pacific plus two tropical depressions. In the North Atlantic DEBBY is heading for Florida's panhandle.
WEATHER ZONES
The South Pacific Convergence zone is sitting over the northern Coral Sea and extends to Tuvalu and Tokelau to Suwarrow. There is a passing tough travelling east from Tonga to Southern Cooks this week, and maybe a squash zone of strong SE winds near Niue from 10 to 15 August.
HIGHS and LOWS
Low L1 was just north of Northland tonight and is expected to travel east along around 33S this week, with its northern extension bringing a slack passing trough to the zone between Tonga and Tahiti.
HIGH H1 is rather weak and expected to move southeast across NZ on Wednesday then fade away.
Low L2 is expected to form in mid-Taman by Tuesday and cross NZ area as a broad trough on Thursday and Friday.
HIGH H2 is expected to build in the Tasman Sea along 35S later in the week and poke a tongue of high pressure along 30S east of the dateline next week, causing a squash zone further north between 10 and 15 August. Avoid.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check metbob.com to see what I offer.
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 Sunday 4 August 2024
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/alCjq_vMeqM
An interesting period of weather occurred when a LOW was blocked in the Tasman Sea from 14 to 24 July under a closed low aloft. As in June there was a dose of rapid cyclogenesis between 19 and 20 July.
The tropics in the South Pacific were quiet.
Sea Surface temperature anomalies from psl.noaa.gov/map/clim/sst.shtml
The Kuroshio current has spread out into the north Pacific. The equatorial Atlantic remains warmer than normal. The cool seas of an El Nino are spreading westwards from Galapagos to the dateline along the equator. A buildup of cold water - melted ice is showing around the Aleutians.
Average isobars for past month as at www.psl.noaa.gov/map/images/fnl/slp_30b.fnl.html
During July the Monsoon spread east across Asia and the subtropical ridge in northern hemisphere intensifies.
Pressure anomalies for past month (below)
The anomaly pressure pattern for July shows a relaxing away of the negative anomalies that were over North America and Australia. South America has built up large positive anomalies.
Around Suth Pacific : Not much change, but the low anomalies in the Tasman have faded.
TROPICS
Typhoon Gaemi weakened to a tropical storm as it made landfall on South China's Fujian coast. Even as a weakened storm, Gaemi's remnants had enough power to kill 22 people in disastrous flooding and mudslides across a wide area of China and parts of North Korea. In total, Typhoon Gaemi was responsible for at least 77 deaths over a two-week period. * Tropical Storm Bud formed briefly
Tonight we have DANIEL and CARLOTTA in the NE Pacific plus two tropical depressions. In the North Atlantic DEBBY is heading for Florida's panhandle.
WEATHER ZONES
The South Pacific Convergence zone is sitting over the northern Coral Sea and extends to Tuvalu and Tokelau to Suwarrow. There is a passing tough travelling east from Tonga to Southern Cooks this week, and maybe a squash zone of strong SE winds near Niue from 10 to 15 August.
HIGHS and LOWS
Low L1 was just north of Northland tonight and is expected to travel east along around 33S this week, with its northern extension bringing a slack passing trough to the zone between Tonga and Tahiti.
HIGH H1 is rather weak and expected to move southeast across NZ on Wednesday then fade away.
Low L2 is expected to form in mid-Taman by Tuesday and cross NZ area as a broad trough on Thursday and Friday.
HIGH H2 is expected to build in the Tasman Sea along 35S later in the week and poke a tongue of high pressure along 30S east of the dateline next week, causing a squash zone further north between 10 and 15 August. Avoid.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more details about your voyage, then check metbob.com to see what I offer.
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.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
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