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

31 May 2008

BOBGRAM7 issued 1 June 2008

Issued 1 June 2008
Bob McDavitt's ideas for South Pacific sailing weather.
(Standard disclaimer: Weather is a mix of pattern and chaos, these ideas
come from the patterned world of weather maps, so please fine-tune to
your place).

The South Pacific Convergence Zone is sitting in a zone from Solomons to
Rotuma to Samoa to midway between Suwarrov and Rarotonga, with Northeast
winds on its northern and eastern side and tropical squalls along its
length. On Tues 3 June UTC the northern end of the trough leaving NZ
will brush past Tonga, drawing the SPCZ south onto Fiji. And on
Wednesday this front will brush past Niue, so that from Thursday the
eastern flank of the SPCZ is expected to between Niue and Rarotonga
offering a challenge to anyone sailing through that area.

South and east of the SPCZ the trade winds are being well maintained.
The subtropical ridge is strongly represented along 30S, sometimes
enhancing the trade winds, especially along 20S.

Galapagos to Marquesas: Satellites are reading a strong east-going
current between equator and 3 degrees S, so get south of that ASAP.
Winds are mostly southerly around Galapagos, so set off to the
Southwest. West of 110 W the winds gradually turn easterly, so head off
for something like 4S 100W then go straight.
It is showery between 110 and 120 W.

The front moving northeast across the eastern coast of NZ is likely to
slow and develop a small low to east of Wairarapa on Queen's Birthday
Monday, making some intense showers over the North Island. This is
expected to be followed by a disturbed southerly flow all week, with
another front moving NE along eastern coasts on Friday 6 June. Avoid
these fronts.

The HIGH in the central Tasman Sea today, Sun 1 June, is a slow- mover
and must wait its turn - will likely to cross NZ on 9-10 June. It is
blocking that low that did form off the Brisbane coast, as picked in
last week's weathergram. This low, or trough, is expected to hang
around for a few more days and deepen to around 1012 near Lord Howe
Island on Friday 6 June and then fade away. Be aware of it if you are
crossing the North Tasman Sea, but it's not expected to produce much-
maybe some squally gales.

The terms used here are more fully explained in the METSERVICE Yacht
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