As always weather is in demand. When internet is available browsing through resources are no problem, there are a lot of sites. I will not deal with here as there are as there are too many sites to count, my favorite is Windy. The issue becomes more interesting with very limited bandwidth.

Weather with limited bandwidth

When faced with limited bandwidth the picture is quite different. Mail is often a convenient interface to use as both HF/SSB and Satellite provide such a service. Getting both synoptical charts etc and grib files can be obtained from saildocs. Just send an email and after some time an email is received with the requested information. When using SSB the response is normally ready by the time sending and receiving mail is progressing. Using Iridium it's better to disconnect and check after some time. The synoptic charts are several tens of kB in size ranging from about 50kB to 80kB, over SSB this is large. GRIB files vary widely in size depending on area and resolution, the GRIB file in the example below was 12.2 kB.

An example:

Compose and send an email to : with subject request (can actually be anything) and a message like :

send gfs:40N,70N,10W,20E|1,1|6,12,24,36,48,72,96|PRESS,WIND

The above example will yield a GRIB file, with the content specified.

Another example is :

send PPVA89.TIF

which will provide a synoptic chart of the north Atlantic.

These files are small and can be received over HF/SSB and Satellite.

For the north Atlantic the files of interest include :

Sea Swell/Wind Direction Analysis (North Atlantic) PJGA93.TIF

24HR Sea Swell/Wind Direction Forecast (North Atlantic) PJGE93.TIF

36HR Sea Swell/Wind Direction Forecast (North Atlantic &Carib) PJLG98.TIF

48HR Sea Swell/Wind Direction Forecast (North Atlantic) PJGI93.TIF

Surface Analysis (North Atlantic) PPVA89.TIF

24HR Surface Forecast (North Atlantic) PPVE89.TIF

36HR Surface Forecast (North Atlantic) PPVG89.TIF

48HR Surface Forecast (North Atlantic) PPVI89.TIF

60HR Surface Forecast (North Atlantic) PPVJ89.TIF

72HR Surface Forecast (North Atlantic) PPVK89.TIF

96HR Surface Forecast (North Atlantic) PPVM89.TIF

120HR Surface Forecast (North Atlantic) PPVO89.TIF

132HR Surface Forecast (North Atlantic) PPVP89.TIF

Mean Sea Isotherm Chart 5 Day Analysis, NE Atlantic & North Sea PTUK21.TIF

One can also request the synoptic charts directly from NOAA, but it's a bit more tricky.

A request email would look like this:

send email to

Subject anything


cd fax

get PPVA89.TIF


However, the reply comes uuencoded, just ASCII text. Save the ASCII text and decode using: uudecode -o PPVA89.TIF uuencoded__get_PPVA89.TIF

where the file "uuencoded__get_PPVA89.TIF" is the encoded text in the body of the email (if uudecode is not installed, you need to install the package "sharutils", run "yum install

sharutils" or "apt install sharutils").

A simple script to download all the charts when internet is available look like this:





for chart in $SYN ; do

echo $chart