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

06 January 2019

Bob Blog 6 Jan 2019



Compiled Sun 06 Jan  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.


To start the New year off, here's  a review of the stats for downloads of the illustrated edition of my weathergram: (/

2018 plateaued (with a slight increase) at over 11,000 view and over 7,000 unique visitors, with around 30 likes and 30 comments.   This is sufficient for me to see a worthwhileness so that I'll continue in weathergrams (which started around 1998). I'm not sure if I've broken any seniority records yet with my blogs – let me know if you think so 😊.

My weathergram also is made available to saildocs-- To get a one-off weathergram via email: 

Send an email to,  no subject needed with message SEND nz.wgrm

There is also an archive with a language translator at

TEXT only edition has been sent out in 2018 via Mailchimp to over 600 email addresses, but I've also started text-only-weathergrams via which also offers , for satellite phones,  a trimmed down to 4-TXT messages edition  (wow).

I may slowly ask people to shift from mailchimp to cruisersat during the next year.  Not sure yet.


To subscribe 

a) to my text-only weathergram, send an email, no subject needed,  from  your vessel's email address  to,  with the message SUBSCRIBE Boat name

or b)  or shortened weathergram for sat phone in four  SMS text messages, send an email,  no subject needed, from  your vessel's email address  to,  with the message SUBSCRIBE Boat name



Sea Surface temperature anomalies as at end of November may be seen at

(parts of US govt are shut down again so unavailable for direct data).

The eastern equatorial Pacific around Galapagos is the focal region for ENSO and is still only slightly warmer than normal.

 The main warm anomaly is now over the Tasman Sea.

There is also a corridor of warmer-than-normal conditions between Tuvalu and French Polynesia— this may add oomph to the South pacific Convergence zone and act as a possible path for cyclones .

The Gulf Stream off the east coast of North America still stands out, which is unusual at this time of the year. 

The last 30 days of rainfall, and its anomaly are seen at

The rain map shows extra convergence over northern Australia to equator/180 and from Tuvalu to Niue, also a drier-than-normal zone between Tokelau and French Polynesia (this zone may well change is the sea surface temperature anomalies are indicative).



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

PENNY was downgraded today but is still heading for northeast Queensland and may redevelop before making landfall.

MONA is category one and after doing a clockwise loop earlier today is expected to curve SE/S across eastern Fiji during tonight and Monday then move off to the southwest.  Also bring lots of rain.

During the past week Tropical Storm PABUK  brought record-breaking rain to Thailand (during their "dry" season).



SPCZ=South Pacific Convergence zone.

The SPCZ is active from Tuvalu to eastern Fiji and is likely to be active from Niue to Austral Islands this week.  MONA is expected to weaken and travel to SW once it has visited the  Lau group, and PENNY is expected to redevelop and make landfall  over NE Queensland around Thursday.


Subtropical ridge (STR)

A new HIGH is expected to travel eastwards from Tasman Sea across New Zealand on Tuesday/Wednesday and then to east of NZ along 40S.

Another HIGH is likely to form off Tasmania on Thursday and travel over Southern NZ on Sat/Sun 12/13 Jan.


Tasman Sea / New Zealand

Troughs are expected to cross southern and central NZ on Monday and Thursday.


Australia to New Caledonia:

With High pressures in the Tasman Sea and low pressures in the Coral Sea this week, the winds favors one-way traffic form Noumea to (southern) Queensland.


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

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Weathergram archive (with translator) is at

Contact is or txt 6427 7762212


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