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

05 October 2008

BOBGRAM7 issued 5 Oct 2008

WEATHERGRAM
YOTREPS
Issued 5 Oct 2008 NZDT
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 below are given in UTC unless otherwise stated.

Addendum to those comments last week about the coming cyclone sea:
Outlook is for neither El Nino nor La Nina, so neutral territory.
Previous years in neutral territory show a REDUCED RISK of cyclones
around Northern Cooks and French Polynesia. For NZ there is an INCREASED
RISK. In-between these places a normal cyclone year may be expected,
and that included the Coral Sea/ Vanuatu area.

I'll be brief this week because it is late Sunday after a weekend of
sailing fro me.

TROPICS The South pacific Convergence Zone, SPCZ, extends from Solomons
to Tuvalu - this branch may move slowly southwards during the coming
week possibly reaching central/southern Vanuatu to Fiji by 15-17
October. Avoid. Another weaker branch of SPCZ extends from Tokelau
across Northern Cooks towards Marquesas. The northern extension of a
mid-latitude front was noticeable from Vanuatu to Fiji and thence to the
Southeast last week (even had some gale warnings), but isn't likely to
appear this week.

Southeast trade winds cover the entire South Pacific-no sign of any
westerly winds yet. Since the subtropics are well marked between 30 and
35S these trade winds are generally strongest along 20S.

SUBTROPICS
One migratory HIGH is moving along 30S, and centred south of Fiji to
French Polynesia on Monday should fade by Wednesday. Next HIGH is
likely to appear in western Tasman Sea on 9 Oct and cross the North
Island along 35S on 11-12 Oct and fade away by 14 Oct.

North of these HIGHs, there will be enhanced east to southeast winds at
20 S.

TASMAN/NZ
Front crossing NZ on Monday Tuesday 6/7 Oct is likely to also bring a
LOW crossing the South Island. Avoid. Severe westerly winds should
follow this front on Wednesday 8 Oct (avoid) followed by a easing
anticyclonic SW flow on Thu 9 to Sun 12 (OK). Spring -type weather.

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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