Bob Blog 15 Dec 2019



Compiled Sun 15 Dec 2019

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.


The Tropics

The latest cyclone activity report is at and TCFP tropical Cyclone Formation Potential at


There are no active cyclones around at present.

There is potential for cyclone formation showing in Micronesia stretching to south of Philippines.


Weather Zones (see text) as expected Wednesday 00UTC showing isobars, winds, waves(magenta) STR, and SPCZ. Pink area = lightning likely (high CAPE)


SPCZ=South Pacific Convergence zone.

The SPCZ is expected to be active all the way across the South Pacific this week from PNG across northern Vanuatu to Fiji, and from Samoa to middle part of French Polynesia . Maybe better to sit back and relax rather than island hopping.

The trend is for this to become more unsettled next week

Passing trough across Samoa on Wed/Thu weakening further east.


Accumulated rainfall for next week from (isobars are for Sunday night).

Subtropical ridge (STR)

HIGH that has been blocking to east of NZ is expected to move off on Wednesday UTC.

Next HIGH is expected to form in the Tasman sea on Tuesday local and gets knocked off to the Ne and fade by Thursday.

Another HIGH may then form in the Tasman by Friday local and then visit norther NZ on Saturday.

Tasman Sea /NZ/Aus

Main feature this week is a 994hpa low expected to cross central NZ on Tuesday local with large swells in the Tasman. followed by a SW flow on Wednesday, and a trough on Friday.

Outlook for next week is more SW flow and a possible low 1007 for Northland on Boxing day. followed by more SW flow. Not a good week to arrive in Northland from the tropics, or to get south for the “summer”.

For Noumea to Aus: A trough and southerly wind change in Noumea on Monday and Tuesday the looks OK.


If you would like more detail for your voyage, then check to see what I offer.

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Weathergram archive (with translator) is at

Contact is or txt 6427 7762212


Published by metbob

Pattern and Chaos

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