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

10 September 2017

Bob Blog 10 Sep 2017



Compiled Sun 10 September 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.


CAT 4 IRMA is damaging parts of Florida as I write this:

Some good news about Cyclone JOSE is that it is expected to do a loop and then stay offshore as it goes north.

KATIA has gone inland, and may end up off the west coast of central America.

Meanwhile over in Northwest pacific, TC TALIM is heading for Taiwan.



SPCZ=South Pacific Convergence zone.

This week, a thin SPCZ is expected to remain across the Coral Sea.  Part of it may visit Vanuatu/ Southern Fiji and Southern Tonga tonight, and then weaken.  A smaller convergence zone may form near 8 to 10S to north and east of Samoa.

A passing, mainly upper, trough, is expected to travel eastwards across Niue on local Monday night and Southern Cooks on local Wednesday, preceded by NE winds, accompanied by variable winds and showers, and followed by SE winds.

Another passing trough may reach New Caledonia area around Monday 18  Sep local.


Subtropical ridge (STR)

HIGH around 1022hPa is expected to move into North Tasman Sea on Monday and then spread east along around 25 to 30S this week reaching south of French Polynesia by end of week.

Another HIGH around 1024hPa is expected to spread from Australia into northern Tasman Sea on Friday.

And then spread along 25 to 30S over next few days.

These High should maintain reasonable trade winds for sailing across the South pacific this week

French Polynesia to the west:

The main obstacle this week is that travelling trough over Niue on local Monday and Rarotonga on local Wednesday.

 Apart from that this should be a god settled week with reasonably steady winds for sailing.

Between  NZ and the tropics:

On Monday and Tuesday, the SW winds and associated large swells over NZ around a LOW to east of the South Island should slowly ease as the Low moves away.

Next front from the Tasman Sea is likely to pass across NZ on Friday,

and then a deep Low may cross southern NZ on Mon/Tue 18/19 Sep.


There may be some gaps between these passing fronts with OK departure for arrival/departure.

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


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