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

27 May 2018

Bob Blog 27May 2018



Compiled Sun 27 May 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.


In the Arabian Sea MEKUNU has made landfall onto Oman and faded away. As seen at

ALBERTO has started toff ten north American Cyclone season slightly earlier than normal and is referred to as a Subtropical STORM  From

And the Indian Monsoon is arriving on time in SE parts of Colombo (As seen at


If we compare the past week’s rain map with the previous week we can see the cyclonic activity in the Arabian Sea and Florida/ Caribbean area  – see



SPCZ=South Pacific Convergence zone.

The SPCZ is expected to stay put from Solomon island to Northern Vanuatu to south of Fiji to Southern Cooks.

A trough with extra wind and rain is expected to travel east across Fiji/Tonga/ Niue on Monday UTC 

Accumulated rainfall for next week  can be seen at


Subtropical ridge (STR)

The STR continues to be weak in the South pacific this week.

The HIGH over the southern Tasman Sea on Monday is helping to feed a polar outbreak by shovelling polar air northwards.

This HIGH should travel eastwards across NZ on Tuesday/Wednesday/Thursday.  And then intensify as it travels off to the east of NZ late this week.


Around Tasman Sea, NZ/Aus to tropics

Some people have been referring recent NZ weather to be a “false spring” with periods of warmth and now a polar outbreak.  However, the nights are noticeably getting longer, and the transition from autumn weather systems to winter weather systems is now complete, with cold fronts reaching as far as 25south.

This week a LOW is expected to form in the south Tasman Sea on Wednesday and the its progress to the east is expected to be delayed by the high on its eastern flank.  This Low is finally expected to travel east across central NZ, with wind and rain, on Mon 4 June, a public holiday in NZ.  

Those travelling to tropics should be able to get far enough north with a Monday departure so as to get to north side of trough when it arrives this weekend, an Ok voyage.   However, a Tuesday or Wednesday or Thursday departure may start in light winds and get caught by the northerly winds ahead of the next trough from Thursday, or in the next trough itself on Sunday/Monday.


New Zealand to French Polynesia

A departure by Wednesday this week looks good. And should be able to ride to polar outbreak.


Galapagos /Marquesas

From Galapagos area to Marquesas, departure can be any time this week. Best path for wind and current is to motor/sail to south of 4S then go to 6S 110W, then follow the current to 7S 128W then go direct. 


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