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

21 June 2008

BOBGRAM7 issued 22 June 2008 NZST

Issued 22 June 2008 NZST
Bob McDavitt's ideas for South Pacific sailing weather.
(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

Galapagos to Marquesas: head direct for 4S 96W then go straight. This
will avoid the strong east-going current and use the winds best: winds
are SE over Galapagos and turn easterly to west of 110W.

The South Pacific Convergence Zone quietened down last week. There was
some increase in activity over Papua New Guinea but some fading in
activity to north of Fiji. This section is expected to drift south onto
Fiji this week, but should not be as strong as it was earlier this
month. A branch of the SPCZ was almost along the some latitude from
northern Tonga to French Polynesia, and this section is expected to
drift north.

There are strong southeast winds in the Coral Sea, and these are being
maintained by the anticyclone that is stalling over Australia. From New
Caledonia to French Polynesia the subtropical ridge is weak and has been
shoved north to 25S, so the trade winds are also weak in this part of
the tropics.

Mid Latitudes
A real wintry week for NZ.

The trough referred to in the last weathergram has arrived over the
North Island. As it moves off to east of the South Island on Monday,
its southerlies will be cold enough to bring some mountain snow.

A southerly jetstream is starting to show itself over Tasmania at
present and this is expected, late Tuesday, to bring unusually cold
southerly winds from to southern ocean onto NZ--- with squalls and
showery show, and with some dollops to sea level.

In the wake of this, on Wednesday to Friday, it looks like a disturbed
westerly flow with gales and heavy swell in the Tasman Sea. Avoid.

On Saturday a LOW is likely to deepen near Chatham Island, bringing
another southerly to NZ for the weekend. There may also be some
reasonable trips from Northland to Fiji/Tonga departing Wednesday -
these trips will experience some squally westerlies and heavy swell near
North Cape.

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