Bob Blog 9 Dec 2018



Compiled Sun 09 Dec 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.


Latest cyclone activity and TCFP tropical Cyclone Formation Potential as seen at or


There are no Tropical cyclones around at present, although there are some potential regions for development near Sri Lanka and to east of Majuro.

Tropical depression 05P/97P was named OWEN last Sunday, and then lost its tropical cyclone credentials (no more a ring of gale winds) on Tuesday, however it has continued has a tropical depression and is still spinning. It seems likely to cross Northern Queensland over next day or so and may deepen again in Gulf of Carpentaria mid-week.

Here are the plots of the main global models for the likely track of OWEN thanks to


There is another tropical Low between 05P and New Caledonia—and this is being watched closely and has been labeled 98P (1000hPa).

The latest isobar ap drawn by Fiji Met also shows another low 997hPa at 23S 165Wand SE of Niue, and Fiji Met are watching this as a possible tropical disturbance in their TC 3 day outlook

See and



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 active between Samoa and Southern Cooks. Part of it may move south and visit Fiji to Tonga on Thursday and Friday.

Accumulated rainfall for next week from CZ= convergence zone.


Subtropical ridge (STR)

HIGH in the Tasman Sea tonight is expected to travel NE and fade near 175E by end of Tuesday. Another HIGH is expected to form over southern NZ on Wednesday and to travel northeast along eastern NZ to be east of Northland by Sunday, extending a ridge back onto Northern NZ early next week.

Troughs around Tasman New Zealand

Trough is expected to deepen off Tasmania on Monday and weaken over Northern NZ on Thursday/Friday. Another Low is expected to deepen off New South Wales on Thursday/ Friday and cross the Tasman Sea over the weekend and visit central NZ mid next-week. Arrange to arrive in NZ between the troughs.

Between Tropics and Australia.

The High moving into Tasman Sea from mid-week means easterly winds from New Caledonia to Australia, good for sailing to Australia. If wanting to go the other way, then depart before mid-week or go well south to avoid the easterly winds.

From Tahiti to Tonga

Active convergence zone this week. May as well stay put.


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