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

24 July 2016

Bob Blog

Issued 24 July 2016

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.

I was on my annual vacation last week in Paihia, and now it's back to the
disturbed weather in Auckland.

The Tropics

Last week I mentioned tropical cyclones CELIA, DARBY and ESTELLE, that had
formed in the central and eastern north Pacific. DARBY (156W) and ESTELLE (140W)
are still going and in the past week FRANK (111W) and GEORGETTE (124W) have been
added to the quick forming list. They all seem to be peeling off to the
northwest .

Elsewhere LUPIT (160E) has formed in the northwest Pacific.

And in the Atlantic, it's been quiet since DANIELLE (in June)- which was the
145th consecutive Atlantic cyclone to fail to bring hurricane winds to the
United States. The last cat3 or higher to make landfall on USA was Hurricane
WILMA in Oct 2005 - more than 10 years ago. Then again in the past 10 years we
have had SANDY (Oct 2012, 2nd most costly), IKE (sept 2008, 3rd most costly)
GUSTAV (two weeks before IKE) and IRENE (Aug 2011, 7th most costly). But they
were less than Cat 3 when the made land fall. Meteorologists are investigating
the reasons behind this anomaly. a slight change in the measuring thresholds
makes a dramatic difference in the observations.


O, And yes, the most costly was KATRINA (Aug 2005)-- it's 11th anniversary is
coming up.

The rain maps from for the past two
weeks show a shift of the most intense rain from central Indian Ocean towards
Indonesia, and a build-up in rain intensity around Micronesia.

SPCZ=South Pacific Convergence zone.
SPCZ is expected to remain draped from north Coral Sea to north of Vanuatu to
Tokelau to Northern Cooks.
This week's SPCZ may be seen on with rain accumulation selected to
ten days.

STR= Sub-tropical Ridge
A weak HIGH cell is expected to spread east across the northern Tasman Sea along
30S on Tuesday and Wednesday, and then again on Sun 31 July/Mon/Tue 1-2 August.

Voyage Outlooks:
Tahiti to the west
It should be a reasonably quiet and dry weak in Tahiti this week - but may be
more unsettled with a passing trough on local Fri 29 July to Tue 2 Aug, so try
and depart before then.
An active trough with squalls and followed by strong SE winds is expected to
affect Tonga around Mon 1 to Thu 4 Aug. Avoid.

Between NZ and the tropics
Disturbed fronts and W to SW winds are expected to cover New Zealand this week
There are three days when these relax-Monday, Wednesday and (sort of) Saturday.
Of these it seems that a Monday departure offers the best opportunity for a
comfortable departure to the north.

See my yotpak at for terms used.
See my website for information on tailor-made voyage forecasts-
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