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

11 March 2018

Bob Blog for 11 March 2018



Compiled Sun 11 March 2018


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.


Just a brief blog this week, for I’m on holiday, touring the South Island.



We are waiting for the remains of HOLA to skirt past northern NZ on Monday/tomorrow. The dangerous quadrant of a southern hemisphere cyclone is the one that is FRONT LEFT of the travelling centre, where the speed of movement adds to the spinning winds. The faster the speed of movement, the greater the danger. It looks like the dangerous quadrant of HOLA may miss NZ



Around northern Australia, the monsoonal rain is continuing, and a Low is expected to form in the Coral Sea this week and drift somewhat to the south. Another Low is expected to form in the Gulf of Carpentaria, and travel west, maybe towards Darwin.


The rain map for last week, at,  shows the track of HOLA.  It also shows the formation of a convergence zone along 5South between Galapagos and the equator. This convergence zone tends to form around this time of the year because this is when the sun is directly overhead these latitudes. Now that it has formed, it may last for several weeks, and so I’ve nicknamed it the Equinoctial Convergence Zone.



SPCZ=South Pacific Convergence zone.

The SPCZ is expected to remain strong this week and help produce a Low in Coral Sea.


Subtropical ridge (STR)

HIGH is expected to form in central Tasman Sea on Tuesday/Wednesday and travel across northern NZ on Thursday.

Next HIGH is expected to form in Tasman Sea on Friday and move travel across central NZ on Sat/Sunday.


Around Tasman Sea

Remains of HOLA should skirt around the NE of NZ on Monday, followed by a Southwest flow on Tuesday.

After a cold front over South Island on Thursday and North Island on Friday, there may be a strong easterly flow over northern NZ on the south side of a Low.


Panama to Galapagos /Marquesas

A departure before Thursday may encounter a longer than normal period of light winds from 80W to 110W.

A departure after Thursday 15 March may have slightly better winds as far as 82W, maybe 85W.



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