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

06 June 2009

BOBGRAM7 issued 7 June 2009

WEATHERGRAM
YOTREPS
Issued 7 JUNE 2009
Bob McDavitt's ideas for sailing around the South Pacific.
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.
Dates are in UTC unless otherwise stated.

TROPICS/SUBTROPICS
The South Pacific Convergence Zone SPCZ has been in its normal June
position over the past week or so - over Solomons to Rotuma to Samoa to
South Cooks area. There are signs that it will slowly spread NORTH
wards and thus eastwards this week, reaching the northern position from
Solomons to Tuvalu to Tokelau to Northern cooks to French Polynesia by
the 13-14 weekend.

Low near 35S 155W is moving south and deepening. It has temporarily
sucked the guts out of the wind over the Cooks, and is rucking up a lot
of southerly swell for the Cook area from 9-14 June.
The SPCZ is likely to be moving from Southern cooks on 7 June to French
Polynesia on 11-12 June. Around 10 June, a low may form near 25S 150W
and deepen as it goes south-- sort of a repeat of the pattern of the
first low, only all happening further east.

A similar pattern may also occur further west---- As a trough crosses
the Tasman Sea on 11-12 June its tropical extension may produce a small
LOW over the Loyalty group around Thu 11 June. And this Low could then
spit out southeast and deepen as it crosses the Minerva/Kermadecs area
on 13-15 June, with a squally southerly change. Not all models are keen
at this stage on this scenario, so this all needs updating closer to the
time.

All quiet on the Galapagos to Marquesas route but winds are weakening
due to a warming sea.

For the record : the SW Indian Monsoon has made it to 15N this weekend
in the Arabian Sea and 20N in Bay of Bengal, and is running around
normal, but slightly behind normal over inland parts of India.

SUBTROPICS
Large HIGH 1028 over Chatham Island area will slowly move east along 40S
this week, reaching 160W by the 13-14 June weekend. There will be a
squash zone of enhanced trade winds on its northern side and this will
affect Samoa/Tonga/Niue on 8-10 June and Samoa to Southern Cooks from
10-12 June. Not so good for fishing this week.

TASMAN /NZ AREA
Northeasterly flow over NZ on Monday is followed by a front on Tuesday.
On Wednesday and Thursday a LOW is expected to deepen and widen in the
Tasman Sea, bringing a NW /northerly flow to NZ. This LOW is forecast
to weaken as it crosses southern NZ on Friday/Saturday, but it could
well be accompanied by a thundery trough, with some heavy rain in
northern NZ on Friday. Avoid.

Anyway, it should be followed by a west/SW flow over NZ on the 13-14
weekend as the next HIGH fills in the North Tasman Sea along 30S, taking
the standard winter track.

Note: It is annual National Fieldays time again... I'll be busy
talking with farmers 9-13 June, maybe able to briefly check emails at
night.

The terms used are more fully explained in the METSERVICE Yacht Pack.
More info at http://weathergram.blogspot.com
Feedback to bob.mcdavitt@metservice.com

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