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

20 December 2015

BOB Blog 20 Dec 2015



Issued 20 December 2015


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.


Summer Solstice is 17:48 NZDT on Tuesday 22 Dec.

It gets later in the year as we get closer to a leap year.


El Nino

This El Nino episode seems to be relaxing now.


Tropical Cyclones

Tropical cyclones are likely to form around the Australian coast during the next week or so, as picked by the Meteo France model


The weather models are not latching into anything specific at this stage,

and the most likely area is around the Gulf of Carpentaria and Queensland coast, so watch that area.


The Weekly rain maps show a continued easing of rain in the South Pacific.

They also show a concentration of rain around Indonesia and especially about the Philippines where a STATE OF CALAMITY has been declared. Half a metre of rain in a week.

See the Weekly rain signatures at



SPCZ=South Pacific Convergence zone.

The SPCZ is rather weak and spread out mainly between 5 and 10S, with a finger stretching to Fiji.

There is expected to be a build-up of convection in the Coral Sea this week.


STR= Sub-tropical Ridge

High that is to NW of NZ on Monday should fade where it is as a front crosses the North Island on Tuesday.

Another HIGH is expected to cross Tasmania on Tuesday and then move towards central NZ for Friday/Saturday

(Christmas/Boxing days). The upper ridge is expected over NZ on 26/27, great for holiday weather, not so good for pasture.


For Sydney-Hobart 2015:

Strong hot northerly flow for a spinnaker start, nasty front on Sun 27th,

then there may be a SW wind change on back side of a developing low.



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