BOBGRAM7 issued 6 Feb 2011

WEATHERGRAM
YOTREPS
Issued 6 Feb 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. Average atmospheric SOI over 30 days to 6 Feb
Jan is \
2.6 (an increase of 0.19 since 22 Jan).

TROPICS
YASI strengthened as it crossed Coral Sea to be Cat 5 when it made
landfall over Queensland-the largest since 1918, devastating. It held
integrity as far as Mt Isa and its moisture caused flash floods over
Melbourne on 5 Feb then dissolved into a trough ahead of which the NW
winds hit 40C in Timaru, NZ, today, Waitangi day. Remarkable.

YASI cleared the Coral sea of its energy, and, according to Australian
academics, has ended this active phase of a Madden Julian Oscillation,
MJO, so that the next phase of cyclones may be with next MJO in March.

However, tropical depressions are still occurring. The one near Raoul
Island should move south and fade away next few days, but may have some
impact in Bay of Plenty/Gisborne around Tues 8 Feb. Avoid.

SUBTROPICAL RIDGE:
Next High is expected to cross Tasmania around 8 Feb and hug 45 S and
cross South Island around 10 Feb, then move off to east of NZ followed
by a NE flow.

NZ Area
The transit of that low from Raoul Island on Tues 8 Feb coincides with a
SW/S change over NZ + some big swells from the Southern Ocean into the
Tasman Sea. Avoid. Next trough should cross Tasmania on Fri 11 Feb and
then southern NZ around 14 Feb.

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