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

31 December 2017

Bob Blog 31 Dec 2017



Compiled Sun 31 December 2017

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.

Happy New Year to all my readers.

In the words of one of the lesser known verses of Auld Lang Syne:


We too have paddled in the stream

From morning sun to night

But the seas between us broad have roared



The Tropics:

Last week we mentioned TD 92S in the Timor Sea and it deepened into TC HILDA and made landfall over NW Australia near Broome.  The first this season.   It is now a rain depression in the interior of Australis, filling in as it heads to Melbourne.

There are some other small tropical depressions in the NW Pacific and in the Indian Ocean, but NO tropical depressions are expected in the coming week in the South Pacific.

Looking at the weekly rain maps from last week and the week before, as at,

we can see pockets of intense convection over NW Australia associated with HILDA,

and decreasing intensity everywhere else.



SPCZ=South Pacific Convergence zone.

The SPCZ is still active to east of 180, but rather weak over the Coral Sea and Northern Vanuatu 


Subtropical ridge (STR)

HIGH1 well to east of NZ near 45S 160W is expected to blossom this week and slow down the progress of the trough on its western side (over NZ).

The next HIGH to the west, H2, should still be in the Aussie bight o Wednesday, and is expected to travel east across the central Tasman sea on the weekend of Sat 6/7 Jan, but may weaken in transit.

Low visiting northern Tasman/NZ later this week.

Trough is crossing Tasman Sea this week. 

Small low is expected to cross central NZ on Monday and Tuesday.

Another Low is expected to deepen in northern Tasman on Wednesday

and deepen further as it travels southeast across northern NZ on Thursday and Friday,

then slowly weaken. Avoid.



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