Bob Blog 3 Oct

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 03 October 2021

REVIEW OF THE LAST MONTH (September 2021)
Sea surface temperature continue to get cooler than normal around the
eastern equatorial Pacific, and that's a hint to a possible LA NINA episode
for the coming cyclone season. A warm pool is starting to build in the
central South Pacific and that may help to tug the South Pacific Convergence
zone eastwards towards French Polynesia.
To see how the annual weather cycle and the seasons are working out, we can
check the average isobar maps for past 30 days and their anomaly from
psl.noaa.gov/map/clim/glbcir.quick.shtml
It's up and down: In the Pacific the northern subtropical ridge has
weakened, and the southern subtropical ridge has intensified near south
America. The southern subtropical ridge has intensified in the Indian Ocean
and weakened in the Atlantic.
The anomaly map shows more HIGHS east of r NZ and lower pressures along 50S
from south of NZ all the way to south of Africa, and that increases the
westerly flow along 45 to 50S.
The drop in pressure over inland Asia is interesting.
Zooming into the NZ area shows the 1015 line shifting south over northern
Australia and north over NZ, indicating spring is in the air with lulls in
the wind over Timor Sea and increased westerly winds over NZ.

TROPICS
There are still some areas of high potential for formation around
Philippines. TC SAM and VICTOR are in the North Atlantic, and SHAEEN-GU is
about to make landfall on northern Somalia.

WEATHER ZONES
SPCZ=South Pacific Convergence zone.
The SPCZ is more active than last week especially from Vanuatu to Fiji until
midweek and then from Solomons to Samoa and over French Polynesia by the
weekend.

HIGHS and LOWS
High1 to east of NZ is expected to travel east along 35S maintaining a good
SE flow between Tahiti and Tonga until mid-week.
Trof1 is expected to cross New Zealand on Monday and move off the southeast.

Low1 is expected to form off Sydney by late Monday and travel SSE to south
of NZ late in the week followed by another trough reaching NZ by Saturday
and a more active Low by Mon 11 Oct.
Low2 is expected to form south of Tahiti late in the week and move off to
the south
Trough2 is expected to cross the northern Tasman Sea on Tuesday. New
Caledonia on Wednesday and Tonga on Friday, leading in High2.
High2 is travelling east across Australia along 30S and should cross the
Tasman Sea along 30 to 35S from Wednesday reaching northern NZ by the
weekend.
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If you would like more detail for your voyage, then check metbob.com to see
what I offer.
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at bottom).
Weathergram archive (with translator) is at weathergram.blogspot.co.nz.
Contact is bob@metbob.com or txt 64277762212
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