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

12 February 2011

BOBGRAM7 issued 13 Feb 2011

WEATHERGRAM
YOTREPS
Issued 13 February 2011
Bob McDavitt's ideas for sailing around the South Pacific.

Disclaimer: Weather is a mix of pattern and chaos; these ideas are from
the patterned world of weather maps, so please fine-tune to your place.
Dates are in UTC unless otherwise stated.

La NINA is still strong, but weakening Average atmospheric SOI over 30
days to 10 Feb Jan is 1.9, a drop of 0.5 so far this month.

TROPICS
South Pacific Convergence Zone SPCZ is now reforming after being cleared
out by YASI last week. It is mainly between 10 and 15S over western
Coral Sea, with occasional tendrils to New Caledonia, and in an
unorganized zone over Tuvalu to Niue, occasionally extending to Fiji.

This week is likely to be quiet in South Pacific. A LOW may form around
New Caledonia at some stage and go west, but should fade by Friday.
Another LOW may form over southern Tonga area at some stage and then
wander SW to south-of-Fiji then track to southeast on weekend of 19-20
Feb.

The MJO activity is starting again over western side of Australia. TC
BINGIZA is about to make landfall over Madagascar, and computer models
are staring to identify possible tropical lows over Gulf of Carpentaria
or going south and following the Leeuwin current along west coast of
Australia this week.

SUBTROPICAL RIDGE:
Some mobile high cells... HIGH1 is wandering northeast and starts this
week at 1030 hear 45S 160W , maintaining a steady trade wind flow on its
northern side.
HIGH2 starts this week crossing the Aussie Bight and should hug 45S as
it goes east , crossing South Tasman Sea on Tue 15 Feb and moving off to
east of Chathams on Thu/Fri 17/18 Feb. At this stage it looks like it
will be followed by a multiplicity of troughs and fronts over the South
Tasman Sea/South Island area from 19 to 21 Feb.

NZ Area
Transitional front between HIGH1 and HIGH2 is moving east off the South
island tonight.

There is a low near Kermadecs (as there was this time last week) and it
should fade as it comes south, but may edge a little to wets and bring
clouds and showers to Northeastern NZ between Tues and Thu 15 to 17 Feb


Apart from the above, it looks like a typical "La Nina weather week"
for NZ with higher pressure to the south and an easterly flow over the
north. This easterly may weaken over next weekend for the Auckland to
Mangonui leg of this year's SSANZ SIMRAD Round NI race.

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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