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

22 October 2017

Bob Blog 22 oct 2017



Compiled Sun 22 October 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.



Now that the tropical cyclone season is almost upon us, here are some links for you to check the latest. The Fiji Met Service watch for disturbances between equator and 25S from 160E to 120W. Even if you have no Internet access, and only email, you can get the latest tropical disturbance advisory by sending an email to,

no subject needed, with the message


Or, for the tropical discussion use


(wait until after 1 November)


Those with access to the Internet can study proceedings from the NZ MetService Tropical page at

This page offers a streamline analysis And specially coloured satellite imagery for watching for rotating cloud tops



TC LAN is bringing wind and rain to eastern Japan tonight, in time for a snap election.

And this is being followed bu tropical depression TD27W which may intensify later this week and head for Japan.



Looking at the weekly rain maps from last week and the week before, we can see a burst of heavy rain in the past week with cyclones between Guam and Japan, also intense rain on the Intertropical convergence zine just south of Hawaii. The South Pacific Convergence zone also shows an intensification in the past week. The Madden Julian Oscillation MJO is in phase with the Western Pacific this coming week, and that suggests we can expect more intensification along the ITCZ in the North Pacific this week.




SPCZ=South Pacific Convergence zone.

The SPCZ is expected to remain lingering in place this week from Solomon Islands to Tuvalu/Tokelau area. It may drift south onto Fiji/Samoa and northern Tonga/Niue next week or around the end of the month.

A passing trough is expected to visit northern NZ to New Caledonia on Monday and South Fiji to Minerva area on Tuesday and Wednesday then fade away. It may contain a few squalls.  Tropical accumulated rainfall for next week can ve seen at


Subtropical ridge (STR)

HIGH is expected to travel east along 30S across the Tasman sea from Monday to Thursday reaching to east of northern NZ on Friday.

Another HIGH is expected to travel across the South Tasman Sea along 40S from Wednesday to Friday, then it may build to east of NZ over the weekend and next week (but models differ on this).


Between Tropics and NZ

The High crossing the Tasman Sea/northern NZ area this week offers a reasonable period of settled weather for getting to NZ. The trough that follows this High is expected to reach northern NZ on Wednesday 1-2 November so try and not arrive on those dates.

If this means arriving a few days later, that’s OK, we can arrange to sail thru the passing trough around 30S where its weak.

The next trough to reach northern NZ is likely around 5 to 6 November.


Between New Caledonia and Australia

Stay put on Monday and let a passing trough get across New Caledonia. Should be OK to depart from Tuesday, but departures on Tuesday to Friday will likely encounter a period of light winds from a passing ridge.

Try and avoid arriving on Queensland coast on late Monday 30 Oct/Tuesday 31 Oct due to a possible passing trough.

Note that New Caledonia and French Polynesia have a public holiday on Wed 1 November.



“The pessimist complains about the wind,

the optimist expects it to change soon,

and the realist adjusts the sails”


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

Feedback to or txt 6427 7762212

Weathergram text only (and translator) is at

Weathergram with graphics is at,

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