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

06 October 2016

Fiji Day tropical Low

FIJI DAY Tropical Low
The GFS model persists in picking that a tropical low may form on Fiji Day Mon
10 Oct and then deepen as it travels SE across Tonga

This could bring brief strong to gale winds to Tonga on Tuesday 11 Oct. But
other models still come up with different scenarios, and, of course, the real
world will do its own thing.

Listening to warnings that are now being issued as TC MATTHEW heads to Florida,
I am reminded that we should hope for the best, but prepare for the worst. And
so when the models differ from each other, as they do in today's run for early
next week, we need good tools so that we can see the difference.

One good tool I recommend in such cases is www.tropical
Select the Southwestern pacific region and it defaults to GFS models and you can
click thru to 12Z Mon 10 Oct= midnight end of Monday Fiji time/1am Tuesday
Tongan & NZ time. This looks yucky for Tonga.
Then the website allows you to click GLOBAL (models) and switch to ECMWF, it
keeps the same timestamp.
Or CMC (the other two options, NAVGEM and JMC, don't work in the Southwestern
Pacific region).

This quickly shows you the difference between the models, and that in itself is
a helpful step. As to trying to surmise what may happen in the real world, well
that takes skill and experience, and is a job for meteorologists. My pick is
the Low may actually be placed SW of Tonga on Tuesday, sort a merger of the
above models.

A similar tool is provided by, which can flick between EC and GFS

Also offers a side-by-side page comparing itt PWG and PWC
models, but this may require a subscription.

Cheers from Bob

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