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

07 February 2009

BOBGRAM7 issued 8 Feb 2009

WEATHERGRAM
YOTREPS
Issued 8 FEB 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.

The moon is at perigee on 8th (today) and is full on 10th so watch out
for king tides on 10th and 11th.

TROPICS
Thumping rain a month ago brought slips and flooding to Fiji. Thumping
rain in past two weeks brought slips and flooding to Solomons. And
thumping rain in past month has produced extensive surface flooding over
internal Queensland. For Queensland it's another week of the same, this
week.

South Pacific Convergence Zone SPCZ has been most active from Queensland
to eastern Coral Sea over past week, and its eastern end has partly
drifted south across New Caledonia over past few days and is tied up
with the LOW near Norfolk Island today. This low is expected to fade by
Tuesday but may bring a rain band onto the North Island.

Another LOW is expected to form offshore Brisbane around Wednesday and
partly move southeast and cross the North Island around Friday 13th.

There is another branch of the SPCZ between Samoa and Southern Cooks.
Rest of tropics are expected to have reasonable east to northeast trade
winds this week.

SUBTROPICAL RIDGE STR / NZ
The STR is about as far south as it gets, indicating this current La
Nina is at work. An intense HIGH is expected to build to over 1030 hPa
in the Aussie Bight at 45S by Wednesday. Its onset should allow cooler
easterly breezes to knock down the heat wave over southern Australia,
and hopefully bring a respite from the killing bush fires.

This big STR is expected to cross Tasmania on Thu-Friday and weaken in
the South Tasman Sea over the weekend. It is a bit of a toss up,
timing-wise, as to whether this High or the
"LOW-from-near-Brisbane-area" reaches NZ first, and there may be a
squash zone between these systems over central Tasman/northern NZ area
either on 13-14 Feb or 15-16 Feb, as picked by GFS. We are unsure at
this stage - EC model, at present, has the Low from Brisbane winning the
race and deepening on Fri 13th when it gets east of NZ and feels the
cooler condensing southerly that precedes the High. Maybe.

For Louis Vuitton Pacific Cup in Auckland the wind outlook is mixed:
Monday, NE, Tuesday NW fading away, Wednesday light and variable,
Thursday a front and mainly NW but may go SW, Friday Southerlies 20
knots plus prevailing, Sat- chance of strong easterlies, then a period
of prefrontal NE winds.

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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