How to receive Weather Faxes

[Paul Elliott]

Originally Posted by Pizzazz

I am not sure what is your concern with the GRIB files. They contain all the info that is on the wfax. Have a look at the surface pressure chart, it is all there. I guess the fronts are missing but you can figure those out, with time and experience.

At least a couple of years ago, even the fine-grained GRIBs didn't show the developing low-pressure systems that can turn into hurricanes -- at least not as well as the hand-annotated WFAX charts. When sailing to Hawaii in hurricane season I like to check the WFAX charts for just this reason.

Yes, the fronts, trofs, and ridges shown on the WFAX charts are nice too, but as you say, I can usually figure that stuff out reasonably well from the GRIBs.

[Paul Elliott]

Originally Posted by conachair

Weird. Coming out same size here


Using web gmail-

to query@saildocs.com
send http://tgftp.nws.noaa.gov/fax/PYBA01.TIF



Must be a reason, what email prog you using?

Yes, really strange! I am using Thunderbird for email here at home, and the PYBA01.TIF file Saildocs sent me is 16.4 kBytes (this shows as 17 KB when I save it). Saildocs claims to be getting the file from

URL: http://tgftp.nws.noaa.gov/fax/PYBA01.TIF
Date: 02 Mar 2018 19:14:20 -0000
Last-Modified: 02 Mar 2018 02:57:09 -0000

but when I fetch it directly from that URL with Chrome, or with my FileZilla FTP client, I get the 32 KB file.

The NOAA FTP site shows the filesize as 32,735 bytes.

So somehow that file is being compressed, and the only place I can think would be at Saildocs.

[CarstenWL]

... if you query@saildocs.com with

- "send PYBA01.TIF" you will receive an image 864 × 723 pixel 17kB in size
- "http://tgftp.nws.noaa.gov/fax/PYBA01.TIF" you will receive the image in 1728 × 1446 pixel with 33kB

Regards,

Carsten

[Paul Elliott]

Originally Posted by CarstenWL

... if you query@saildocs.com with

- "send PYBA01.TIF" you will receive an image 864 × 723 pixel 17kB in size
- "http://tgftp.nws.noaa.gov/fax/PYBA01.TIF" you will receive the image in 1728 × 1446 pixel with 33kB

Regards,

Carsten

That makes sense. I was going to try that, but you beat me to it. The Saildocs-compressed file is completely readable.

[er9]

is there a command to get auto updates longer than 14 days?

[Paul Elliott]

Originally Posted by er9

is there a command to get auto updates longer than 14 days?

Sorry, I don't know how.

But why would you want to? Five days is usually decent accuracy in a general way, beyond ten days is getting into the pure fantasy range. If I am letting my computer do weather-routing with GRIBs and my polars, I let the program extend the last GRIB forecast which might be six days out. Why waste airtime getting completely unreliable data?

[conachair]

Originally Posted by CarstenWL

... if you query@saildocs.com with

- "send PYBA01.TIF" you will receive an image 864 × 723 pixel 17kB in size
- "http://tgftp.nws.noaa.gov/fax/PYBA01.TIF" you will receive the image in 1728 × 1446 pixel with 33kB

Regards,

Carsten

Ah, mystery solved,thank you.
I did try just the file name with another file and it came back with an error. Maybe they keep a local cache of some files compressed.

[Bleemus]

Used one of these for years . . .

[er9]

Originally Posted by Paul Elliott

Sorry, I don't know how.

But why would you want to? Five days is usually decent accuracy in a general way, beyond ten days is getting into the pure fantasy range. If I am letting my computer do weather-routing with GRIBs and my polars, I let the program extend the last GRIB forecast which might be six days out. Why waste airtime getting completely unreliable data?

I guess I don't understand yet how this system works. I just learned about it reading this post. I assumed the weather data/report was updated regularly and that getting auto updates would send the most current update not a two week old computer simulation.

[Bleemus]

Originally Posted by er9

I guess I don't understand yet how this system works. I just learned about it reading this post. I assumed the weather data/report was updated regularly and that getting auto updates would send the most current update not a two week old computer simulation.

You are correct. Each successive broadcast is the latest info available.

[Paul Elliott]

Originally Posted by er9

I guess I don't understand yet how this system works.

GRIBs are a forecast, covering up to several days in the future. The NOAA computers provide forecasts for *now* (current conditions as of the last computer run), now+3 hours, +6, +9, ... +189, +192 hours. You can request any or all of these forecasts. The entire set of forecasts is updated four times a day.

(The above relates to the NOAA "GFS" model. There are others, but they are similar in what they provide.)

For more on how to specify the details for your request, look here: Requesting grib files from Saildocs (2010-07-08) This is for request and delivery via Saildocs email. There are other ways to obtain GRIB data.

[er9]

Originally Posted by Paul Elliott

GRIBs are a forecast, covering up to several days in the future. The NOAA computers provide forecasts for *now* (current conditions as of the last computer run), now+3 hours, +6, +9, ... +189, +192 hours. You can request any or all of these forecasts. The entire set of forecasts is updated four times a day.

(The above relates to the NOAA "GFS" model. There are others, but they are similar in what they provide.)

For more on how to specify the details for your request, look here: Requesting grib files from Saildocs (2010-07-08) This is for request and delivery via Saildocs email. There are other ways to obtain GRIB data.

thanks I will check out that link.

the command I used to get the 14 day .TIF subscription from saildocs was "sub PYBA01.TIF time=00:00 interval=6"

If I'm understanding the format correctly this sends me the most current update four times a day starting at 00:00 for 14 days?

[unbusted67]

Originally Posted by Bleemus

Used one of these for years . . .

Attachment 165368

Weather messages decoder - RTTY, NAVTEX, WEFAX (HF-FAX), NWR SAME software

Again, not necessary. Just hook your SSB or HAM up to your laptop with this software and it will act as a fax.

Why is everyone on here talking about FTPs and Iridium Go? This is far, far cheaper and way lower-fi ie less parts to break.

[philiosophy]

Yes those pesky fronts. In these parts identifying said fronts and the direction they are taking is sooooo very important. It is my belief the NOAa weather charts are written by real meteoroligists two maybe three times a day. Grib files are nice and easy to read. Just not that much recent human content. The waters between NZ and the Islands north of us are serious business....

[Bleemus]

Originally Posted by unbusted67

Weather messages decoder - RTTY, NAVTEX, WEFAX (HF-FAX), NWR SAME software

Again, not necessary. Just hook your SSB or HAM up to your laptop with this software and it will act as a fax.

Why is everyone on here talking about FTPs and Iridium Go? This is far, far cheaper and way lower-fi ie less parts to break.

He indicated he was not confident his SSB was working properly. These units are stand alone if you attach an antenna. Used one for ten plus years all around the world. No satellite fees, no Sailmail fees. They just work.