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Bob McDavitt's ideas for sailing weather around the South pacific

25 September 2022

Bob Blog 25 Sep

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 25 September 2022

TC FIONA
After devasting Puerto Rico, Tropical Cyclone Fiona travelled north and did
an extra-tropical transition with cold air wrapping around and squeezing off
the warm core. It then made land fall over Port aux Basques in Nova Scotia,
Canada, with a measured baro of 913hPa, a new Canadian record.
twitter.com/i/status/1572761254153920512
twitter.com/i/status/1573776053453164552
twitter.com/i/status/1573539748466999296
twitter.com/i/status/1573582481026162700
twitter.com/i/status/1573534734805868546

The storm surge washed away houses:
twitter.com/i/status/1573659603417579522

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

We are having the late September flush with 6 cyclones.

IAN is approaching Florida, while GASTION and HERMINE are also in the
Atlantic and NEWTON is in the eastern Pacific. NORU is moving onto the
Philippines.


WEATHER ZONES
SPCZ=South Pacific Convergence zone
The SPCZ stretches from Coral Sea. L2 is forming east of Fiji and expected
to go to Tonga. Avoid.

HIGHS and LOWS
Low L1 in mid Tasman Sea is expected to go southeast to south of Aotearoa
NZ.
Low L3 east of Aotearoa NZ is expected to travel off to the northeast
followed by H1.
Low L4 is expected to form over New South Wales by mid-week and then travel
towards North Island by early October. Avoid.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for 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 txt 64277762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

18 September 2022

Bob blog 18 Sep

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 18 September 2022
Origin of the terms El Nino and La Nina
The locals in Peru are keen observers of ups and downs in their food stocks
over the years. They like to gather anchovies that can be easily collected
just offshore thanks to the strong upwellings of nutritious water in the
Humboldt current. Around Christmas in most years a current brings in warmer
seas from the north and a bounty of extra food, and Peruvian fish gatherers
called this event" El Nino" naming it after the birth of the Christ child.
The first published reference of this was in 1891 by Senor Dr Luis Carranza,
then President of the Lima Geographical Society, see
faculty.washington.edu/kessler/occasionally-asked-questions.html#q2
So, what about the origin of the term "La Nina"? Well, the locals in Peru
didn't have a term for a non-bounty period and when the term "El Nino" was
adopted for a warm event over the eastern equatorial Pacific, various terms
were used to describe its opposite. One was "Anti El Nino", but that can be
translated as antichrist and was only used once or twice.
So it was that S. George Philander of Princeton introduced the term "La
Nina" (Girl) for the "cold event". But some wanted to use "El Viejo" (old
man).

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

FIONA is in the Caribbean and MADELINE is off west of Mexico
TC NANMADOL is tonight making landfall across Japan.
Two million people have been asked to shelter from this rare and very
dangerous

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Samoa and fades further east.
A trough in the Coral Sea is expected to deepen into a Low (L4) mid-week and
that then fades over New Caledonia by end of week. Avoid.
HIGHS and LOWS
HIGH H1 east of Aotearoa NZ expected to travel east-southeast from 35S to
40S.
A warm front is expected to travel south across Aotearoa NZ on Monday and
then a broad meridonal trough by midweek with lows L1 at 43S and L2 at 23S.
Low L1 expected to travel southeast across central Aotearoa NZ on Monday
followed by strong southerly flow on Tuesday with rough seas.
High H2 is expected to travel across the Tasman Sea on Wednesday followed by
L3 on Thursday and Friday, avoid.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for 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 txt 64277762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

11 September 2022

Bob Blog 11 Sep

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 September 2022

La Nina or not?

El Nino and La Nina are opposite ends of the swing of an identifiable
tropical influence on our seasonal weather.

The La Nina, caused by cooler than normal sea surface temperatures along the
equatorial eastern pacific, (STEEP), shifts the subtropical ridge away from
the equator and strengthens the trade winds.

The El Nino, with warmer than normal seas, draws the subtropical ridge
closer to the equator, weakening the trade winds.

Their comings and goings can last several months, maybe years, and so their
status can be used to help forecast the weather for the coming season.

Isobars
ENSO = El Nino/Southern Oscillation. The main parameter we watch from the
atmosphere is the Southern Oscillation Index SOI (30 day running mean) as it
sums up the whole weather pattern across the South Pacific into one number,
based on the number of isobars between Tahiti and Darwin, The SOI is the
normalised Tahiti minus Darwin barometer reading. When this is more than
plus one there is usually a La Nina event.
See www.bom.gov.au/climate/enso/wrap-up/

LA NINA EVENTS: We had it strong from Dec 20 to March 21, weaker peaks
July/Aug 2021, and Nov 21 to Jan 22, and a strong again May to July 22. We
are now "in-between events" with the SOI hovering around plus one. The SOI
has been mostly positive since Aug 2020, and some meteorologists are
wondering what this means --- see www.nature.com/articles/d41586-022-01668-1
and reliefweb.int/report/world/el-ninola-nina-update-august-2022

The Ocean:
The sea surface temperatures in the equatorial eastern Pacific have been
cool for a while but are currently mixed with a warm tongue between
Galapagos and Peru.

In passing, the warm seas in the northern hemisphere are remarkably red.
territory.

The warmer than normal ocean between Indonesian and Australia is a NEGATIVE
IOD (Indian Ocean dipole). This is associated with a wet Spring for eastern
and southern Australia and usually tugs the monsoon eastward off India (but
maybe not at present).

Sea temperature anomaly is at psl.noaa.gov/map/clim/sst.shtml

NINO3.4 is the parameter mostly used from the ocean for watching ENSO and
recently this has been hovering on the threshold,

Other factors now considered are the sub-surface temperature, the height of
the sea, cloudiness, and the trade winds. The combination of several
parameters and models are then summarised into a forecast for NINO3.4 for
the months ahead. The trend is looking neutral. See
www.bom.gov.au/climate/enso/wrap-up/

TROPICS
The latest cyclone activity report is at tropic.ssec.wisc.edu and Tropical
Cyclone Potential is from www.ssd.noaa.gov/PS/TROP/TCFP/index.html

EARL has wandered along the Gulf stream to the North Atlantic. MUIFA is
travelling north to east of Taiwan and FIFTEEN is also in the NW Pacific.

WEATHER ZONES
The SPCZ stretches from PNG across Solomons to Samoa and fades further east
by southeast. A trough in the Coral Sea is expected to deepen into a Low
(L2) over New Caledonia by mid-week and then travel southeast towards
Northland by Saturday. Avoid arriving in NZ around 23/24 Sep.

HIGHS and LOWS
HIGH H1 east of Aotearoa NZ expected to travel east-northeast from 40S to
35S.

Low L1 expected to travel southeast across central Aotearoa NZ on Monday
followed by strong southerly flow on Tuesday with rough seas.

High H2 is expected to travel along 45s into Tasman Sea by mid-week and then
across southern Aotearoa NZ by end-of-week, with a squash zone of easterly
winds with L2 on its northern side.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for 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 txt 64277762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

04 September 2022

Bob Blog 22Sep

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 September 2022
Monsoon 2022

U.N. Secretary-General Antonio Gutteres said Pakistan's flooding, caused by
weeks of unprecedented monsoon rains and compounded by glacial meltwater
running down from the mountains, were a signal to the world to step up
action against climate change.

"Let's stop sleepwalking toward the destruction of our planet by climate
change,"
he said in a video message to an Islamabad ceremony launching the funding
appeal.

"Today, it's Pakistan.

"Tomorrow, it could be your country."

REVIEW OF THE LAST MONTH (August 2022)

MetService issue a tropical analysis of the South Pacific with isobars and
streamlines at www.metservice.com/warnings/tropical-cyclone-activity

I am now saving one image a day from this page and here is an animation of
last month's weather at this link: tinyurl.com/PacificAug2022

Between 15 and 20 August a strong "atmospheric river" brought flooding to
parts of Aotearoa NZ open to northerly winds, as a HIGH over 1040hPa south
of Tahiti stalled fronts in the Tasman Sea.

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


The main pattern remains the same as in July with the coo waters f La Nina
along the EEP Eastern Equatorial Pacific surrounded by a C shaped zone of
warm waters

Average isobars for past month
The subtropical ridge in the northern hemisphere has weakened. Otherwise
there hasn't been much change.

Pressure anomolies for past month (below)
The lower pressure zone that was over Canada has shifted west into the north
Pacific. And the low zone that was over Australia has relaxed.A Higher than
normal pressure zone persists from south of Australia across NZ into the
Pacific, encouraging the southern hemisphere's subtropics .

Zooming into the NZ area
The subtropical ridge around NZ has shifted north, and intensified,
increasing the trade winds. High centres have intensified to over 1025 in
Indian and East South Pacific Ocean.


TROPICS

After a quiet August, things are ramping up in September with Danielle and
Earl in the North Atlantic, Javier west of Mexico and Hinnamnor still
affecting east of Asia.

WEATHER ZONES

The SPCZ stretches from PNG across Solomons to Samoa and fades further east
by southeast. A trough in the tropics is expected to visit New Caledonia on
Monday and get eats to south of Fiji/Tonga by mid-week followed by southerly
swells to 3m. Avoid.

HIGHS and LOWS

Low L1 in mid Tasman deepening to 988 over Northland by Monday night/Tuesday
while a cold southerly blast cover N, combining to produce up to 7m swells
on its backside. Avoid

The trough associated with L1 is expected to brew L2 to SE of Niue by
Thursday and then off to the southeast for a few days.

High H1 should spread into South Tasman Sea by Wednesday and across NZ on
Thursday then travel east along 45S and should be useful for sailing.

A trough following H1 is expected to cross the Tasman and NZ this
weekend/next Monday.

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If you would like more detail for 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 txt 64277762212
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

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