Bob Blog 21 May

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 21 May 2023

Bye Bye to Radiofax

The following is based on the MetService webpage

What is Radiofax

Radiofax (also known as HF Fax or Radiofacsimile) is an analogue broadcast using high frequency (HF) radio waves to transmit images over long distances.

The technology is almost 100 years old and has been adapted for telephone use as fax machines. The Radiofax service is one method that MetService has used to transmit weather maps.


Nowadays, Radiofax equipment is scarce, difficult to service, costly to maintain (especially transmitting equipment), and the technology has now been superseded by the likes of HF email or satellite-based internet.

Retirement of Radiofax

MetService will retire its Radiofax broadcast service from 1 July 2023.

The MetService weather maps transmitted through Radiofax will however continue to be produced and available on the website also on a low bandwidth page which is designed for users with more limited or paid data connections (such as via satellite) to minimize download size and cost.

What’s not changing?

The more safety critical oceanic/high seas warnings and forecasts (English text) will continue to be produced and broadcast through all existing channels/services, including internet, email, radio broadcast, and satellite broadcast under the International Maritime Organization’s (IMO) Global Maritime Distress and Safety System (GMDSS). For more information about the GMDSS, see the World Meteorological Organization’s (WMO) website for the Worldwide Met-Ocean Information and Warning Service (WWMIWS).

If you would like to get in touch with MetService

about this change, please contact

Modern solutions

Satellite phones and internet connections enable up to date weather information and forecasts (such as maps of pressure, wind and waves) to be directly displayed within onboard Chart plotters or Multi-Function Displays (MFDs). These can now provide skippers with a much richer source of information that can be integrated with other navigational maps and vessel data in digital devices.

To request a download of the latest SUBTROPIC high seas forecast, send an email to, with message:




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


Cyclone MAWAR is expected to cross over GUAM on Tuesday night/Wednesday then move to northwest. FABIEN has formed in the South Indian Ocean and is somewhat out of season.

The MJO, a burst of extra energy in the tropics, is travelling across the Pacific this week.


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


CAPE maps mid-week GFS and EC from Predictwind, showing the chance of lightning.


Rain Accumulation next five days from


The South Pacific Convergence zone is expected to do some rebuilding over the Coral Sea to Fiji area this week. A trough might form near New Caledonia late in the week and cross Fiji and Tonga over the weekend or early next week.


Another busy week for Tasman troughs.

Low L1 is forming tonight on a cold front now half-way across the Tasman and expected to deepen to 995 NW of Auckland by Monday night, then move off to the east on Tuesday. Avoid. Its tight isobars will generate large swells. A burst of 3+m swells may reach Noumea on Tuesday and Minerva on Wednesday.

High H1 should move over central NZ on Thursday, bringing a brief respite.

Low L2 is expected to form on a cold front when it reaches Sydney on Friday, and then move into the central Tasman Sea over the weekend. More swell.

The gulf of Panama = Light winds or SW winds this week=no good for Panama to Marquesas.


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

Or Facebook at /

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

Weathergram archive (with translator) is at

Contact is or txt 64 277762212



Published by metbob

Pattern and Chaos

Join the Conversation


  1. Hi Bob,

    I’ll wager modern electronic equipment will never be as reliable as our ancient Icom m700. Discontinuance of wefax HF transmissions is the worst news in a long time – I can live without GPS, but radiofax! I’ve come to rely on this tried and true technology. And only one month’s notice – very inconsiderate.

    I wonder if you can enlighten your followers further on the alternatives available after next month – how to get wefax on the high seas after July without spending a fortune on newfangled gadgetry and associated rental costs of satphones, satellite internet, or whatever we are being forced to adopt at likely prohibitive cost.

    Do you know if the Australian VMC fax transmissions for SW Pacific will continue or will we lose those also in the near future?

    Many thanks, Christine and Hugh Cameron ZMX2356


  2. Fair comment. I’ll check and report back on AUS Radiofax (but their transmittord may be hard to pick up in South Pacific) and comment more on alternatives in my next blog.

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