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

25 January 2014

BOBGRAM issued 26 Jan 2014

Issued 26 January 2014
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.

Just a quick edition this week-we are busy celebrating my mums 90th!

SOI The Southern Oscillation Index SOI (30 day running mean) sums up the
weather pattern over the South Pacific as one number. It is based on the
standardized difference in the barometer readings between Tahiti and Darwin.

SOI has bounced back up in the past few weeks. Its 30-day running mean was
plus 0.81 on 25 Jan.

There is a tropical depression forming in the Coral Sea by Monday and this
is likely to develop into a Tropical cyclone by Wednesday and may then head
for the Queensland coast (GFS), or maybe for the New Caledonia/Tasman Sea
area by the end of the week (ECMWF)

By mid-week there is also a good chance of a tropical depression developing
over the Fiji area and then moving SE to the east of NZ.

South Pacific Convergence Zone SPCZ
This is very active in the Coral Sea at present and expected to get very
active over Fiji by mid-week. It is active between Samoa and French
Polynesia early in the week, but this branch is expected to ease during the

Sub-tropical Ridge STR
The HIGH in the Tasman Sea is expected to stay there all week and then
weaken and maybe poke the tongue of a ridge onto the South Island on weekend
of Sat 1/2 Feb.

New Zealand area
Troughy, yet again, but not as much as last week. . An active front is
crossing the North Island tonight followed by a strong southerly flow on
Monday. For the remainder of the weak NZ is expected to have a SE flow
between a HIGH in the Tasman and a trough that is expected to stay between
Fiji and the dateline.

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