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

04 December 2010

BOBGRAM7 issued 5 Dec 2010

Issued 5 December 2010
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: Average atmospheric SOI over past 30 days is 1.69, up a bit
from 1.5 last week.

South Pacific Convergence Zone SPCZ had a week off in the Coral Sea as
all that activity hat was over Fiji last week went across Tonga/Niue and
to south of Kermadecs. The remainder of this is expected to fade and
wander off to east on Mon/Tue 6/7 Dec.

A burst of convection occurred along the Queensland coast over the past
few days, but this is already fading and should be gone by end on Monday
6 dec.

A new SPCZ is likely to form over north Coral Sea this week and wander
south to be from Vanuatu to Fiji by 11/12 Dec. Enhanced convection
along this SPCZ is likely from 15 to 20 Dec due to an incoming Madden
Julian Oscillation--- more about that in next weathergram.

High near Northland on Mon 6 Dec should fade away on Tues 7 Dec.
High crossing South Tasman Sea on Tue 7 Dec should expand to NE by Fri
10 Dec and then expand as it wanders east along 35S, making a squash
zone of enhanced trade winds on its northern side.

NZ/Australia AREA
Trough between the highs may bring showers- one of these troughs crosses
NZ on Mon 6/ Tues 7 Dec bringing a southwesterly change.

The next moves off Sydney on Thu 9 Dec, onto Brisbane and Southland on
Fri 10 Dec, central Tasman and central NZ on Sat 11 Dec, and then onto
North Island around Sun 12 Dec. By then there may not be much left in
this front, so it shouldn't put anyone off trying to approach Northland
from the north.

The terms used are more fully explained in the METSERVICE Yacht Pack.
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