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

08 January 2011

BOBGRAM7 issued 9 Jan 2011

Issued 9 January 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 Southern Oscillation Index
SOI over past 30 days is 2.3 (a drop of 0.16 in the past week). Dec SOI
was 2.7, a new Dec record and we have to go as far back as Nov 1973
(3.16) to find a higher SOI. This indicates the extent of abnormality
in recent Australian weather maps. Oceanic Nino Index for Sep-Oct-Nov
is -1.4

South Pacific Convergence Zone SPCZ lies mainly from central Coral Sea
across Vanuatu to Samoa and then SE to east of Niue. This is currently
activating between Vanuatu and Fiji and a Tropical Low has formed near
17S 172E.

This system is expected to go SW and pass by close to south end of
Vanuatu, then south then go SE and peak near 25S 173E around Fri 14 Jan
and then weaken over or near North Island area on Sun 16 mon 17 Jan.

Equatorial westerly winds are still well west, just entering the
western Timor sea this week. They are late. A tropical low system should
form off NW Australia around Friday 14 Jan and move off to the SW.

High in South Tasman Sea is expected to stay there and fade away
allowing a trough and SW outbreak to cross eastern NZ on Wed 12/ Thu 13
Jan . Then a new High 1032+ should roll in from Australian Bight and go
NE across Tasman Sea on Thu Fri 13-14 Jan , and then move quickly away
eastwards along 37S on Sat 15 Jan.

So we have a mobile high crossing the Tasman Sea - this will be useful
for those seeking to escape from Queensland.

By Thu 13 Jan Low from central Australia (full of monsoonal moisture) is
expected to move south across Adelaide area and into Australian Bight.
This Low should then wander east along 50S, affecting Tasmania on Fri 14
and Southland on Sun 16. Avoid.

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