Bob Blog 3 Nov 2019



Compiled Sun 03 Nov 2019

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.


Sea Surface temperature anomalies as at start of October compared with the start of November may be seen at

Early October (below)



Early November (above)

The anomolies in the North Pacific are starting to relax. There is a new build up in heat in the Tasman Sea and Southwest Indian ocean

To see how the annual weather cycle and the seasons are working out, we can check the average isobar maps for past 30 days and their anomaly from

Average for September 2019 (below)



Average for October 2019 (above)

Anomalies   September2019 (below)



Anomalies October 2019 (above)

There has been a change in the anomaly pattern during the last month, with a relaxation of the High anomaly over Australia, and the swap, south of Africa, from higher-than-normal to lower-than-normal.

Zooming into the NZ area, and comparing monthly anomalies for end of last month with now, (but with a change in the colour scale), shows that the subtropical ridge STR has weakened and it’s most intense spot has shifted from eastern Australia to west of Australia. Isobars over NZ have weakened, with the 1010hPa isobar in much the same place as last month, and 1005 hPa now further south. There is still mainly a SW flow over NZ, but it’s weaker than it was.







The latest cyclone activity report is at and TCFP tropical Cyclone Formation Potential at

At present there are there named storms MAHA, MATMO(weakening) , and HALONG, and strong potential areas in China Sea and around Guam .



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 expected to have an active week over PNG, some activity over northern Vanuatu and northern Fiji, and be weaker than normal further east to Samoa.

Weak convergence zone between Samoa and French Polynesia at times this week.

Burst of SSW swell around 3m affecting as far north as 18S this week due to a deep low near 40S.


Accumulated rainfall for next week from

Subtropical ridge (STR)

HIGH is expected to cross northern NZ by Tuesday and then travel east along 30 to 35S. Next High from Australia may reach Tasman sea by Sun 10 Nov.

Tasman Sea /NZ/Aus

Trough over eastern Aus coast with thunderstorms on Sunday/Monday turning into a Low east of Coffs by Tuesday then going off to S and fading on Wednesday. Broad trough in Tasman by Friday, crossing NZ and Fiji on Mon 11 Nov.

For Noumea to Aus, no good this week: has a passing trough that reaches Noumea around Wednesday. Then westerly winds along the route


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

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Weathergram with graphics is at (subscribe/unsubscribe at bottom).

Weathergram archive (with translator) is at

Contact is or txt 6427 7762212


Published by metbob

Pattern and Chaos

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