|S/V Hoku Pa'a
Weather Charts and Weather Fax
We use weather information en-route
to help fine-tune our course. Generally we want to avoid areas of
excessively high or low winds, developing storms, or direct head winds.
Even though at 6 knots (about 11 km/h) we can't outrun bad weather
when it's chasing us, we can head to where it might be less nasty.
We receive this weather information
via HF shortwave radio. There are voice broadcasts, such as station
WWVH (from Hawaii on 5, 10, 15, 20 MHz at 48 minutes past each hour), and
there are weather maps. Weather maps (also called weather faxes) are transmitted by coast stations such as KVM (Hawaii), and
we receive them by tuning the shortwave receiver to the right frequency at
the start time, and attach the headphone output to our laptop's microphone
input. Software on the laptop (http://www.jvcomm.de)
decodes the fax data and shows us the picture. It takes a lot longer to download
than a regular fax, about 20 minutes, and depending on the radio reception
the quality can be quite variable, but they are handy.
A second way of receiving weather faxes is via email. A satellite phone or HF radio modem (which we have) connects to an email provider on shore, which sends the weather fax as an attachment. The email option has the advantage of being faster, but more expensive.
A typical weather fax can be seen here. Some
resolution in the original file has been lost while making it a reasonable
size for the web site (the original is more than 300kB) but you get the idea.
If you are interested in this topic,
the symbols on the weather fax and the various available products are explained at https://www.weather.gov/marine/radiofax_charts.
This website also posts the same weather faxes that we receive over
the radio. You can also go to www.weather.gc.ca
as another source of weather information.
|S/V Hoku Pa'a
1000 DeCosta Pl.
Canada V9A 6Y3
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