Bob Blog 2 Oct

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.

Compiled Sunday 2 October 2022


Sea Surface temperature anomalies from


The main pattern remains the same as in July with the cool waters of La Nina along the Eastern Equatorial Pacific surrounded by zones of warmer than normal conditions in the north and south Pacific.

Average isobars for past month (below)



This pattern is much the same as at the end of August.

Pressure anomolies for past month (below)


The main change in the past month has been the appearance of lower than normal pressures over and around North America.

The lower pressure zone that was over Canada has shifted west into the north Pacific. And the low zone that was over Australia has relaxed.

Zooming into the NZ area

Last month is below



Previous month os above

The subtropical ridge is slightly weaker east of Aotearoa NZ otherwise the pattern is very similar. .


The latest cyclone activity report is at and Tropical Cyclone Potential is from


Cyclone IAN made historically damaging landfall over Florida last week with a death toll over 20 and still rising.

Here is a clip showing four vessels drifting down along a street at Fort Myers on the SW tip of Florida

Tonight ORLENE is about to make landfall on west coast of Mexico and ROKE is moving away from Japan.


Weather Zones Mid-week GFS model showing isobars, winds, waves (purple), rain (red), STR (Subtropical Ridge), SPCZ (South Pacific Convergence Zone) CZ (Convergence Zone) and CAPE (lime)


CAPE maps from Predictwind, showing chance of lightning and position of features tonight



Rain Accumulation next five days from

The SPCZ stretches from PNG across Solomons to Vanuatu and to a trough that lingers over the Fiji area this week and may form a low L2 northwest of Fiji by end of week.


High H1 lingering south of Tahiti and slowly travelling East along 30S.

Low L1 crossing Aotearoa NZ tonight followed by a cold southwest flow for a few days, with a trough extending back to Fiji.

HIGH H2 over 1030hPa travelling northeast across southern Tasman Sea and central Aotearoa from Wed to Sat, with a squash zone of enhanced easterly winds o its northern side.

Low L2 is expected to form northwest of Fiji this weekend as H2 moves off to east of Aoteroa.


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