Re: New LDM server for EMWIN-only feed

As an additional . . . I run the script in cron every minute, even when NOAAPort is up . . . it certainly doesn't hurt anything.

On Apr 28, 2007, at 12:19 PM, Gilbert Sebenste wrote:

Hello all,

As you know, last Saturday we had a tornado outbreak in Texas, and the National Weather Service (NWS) NOAAport feed went down. When a satellite broadcaster interfered by sending a rogue signal on the same frequency that NOAAPort broadcasted on, it knocked just about everyone's data feed out in the U.S., from the UNIDATA community, to the short, almost all external NWS data users. When this happened, the only ways to get data were:

1. NOAAport feed fed directly by fiber from the NWS (very expensive)

2. Family Of Services, a slower speed with fewer text products and model data, but high speed radar (also very $$$$)

3. NOAA All-Hazards Radio (fed by the AWIPS WAN)

4. Some NWS web sites (and not all data were available, especially on NWS Region servers)...and they were generally very slow as everyone hit them when the NOAAport feed went down


Should this ever happen again (it will), I have now set up an LDM server that grabs the EMWIN feed via the Internet in near-real time. Because of EMWIN's slow data feed (9600 baud), and how the NWS sends out the files on their public server, there is a delay of about 2-3 minutes with the feed in total. However, when you're in a tornado outbreak and you have nothing else, you'll take ANYTHING you can get your hands on!

So in that vein I am pleased to announce a new EMWIN feed site that is fed directly from EMWIN's public FTP server. Here are the caveats/legal stuff:

1. Data delayed a minimum of 2 minutes

2. Unsupported in that I won't have much time to work on it if it goes down

3. This is an unofficial feed; as is, with all legal disclaimers applying that you should not use this feed to save your life or the lives of others, or use in any official way so that you don't get into trouble when the warning comes in too late, or not at all if the feed is down, etc etc etc.

4. I reserve the right to terminate the feed if my office gets hit with a data outage; this server is used as a backup in case my main office building has a major network connectivity problem that last for days or weeks or longer. If that happens, I will feed NOAAport to this backup machine and shut off EMWIN and access to all except those who have already requested a NOAAPort feed from me. That hasn't happened in the 8+ years I've been here, but you never know.

5. How do you save the images and what is available on the EXP feed? Sorry, I don't know, and won't have time to play with it. I can grab satellite/radar via the Internet and with more current data, so I don't care. OK, disclaimers aside...

HOW I DO IT: Using a script developed by Stonie Cooper from Planetary Data, Inc. (Thanks, Stonie!) under the GNU Public License, it downloads the data from the public NWS EMWIN server which itself updates with all products sent over the last 2 minutes; I grab it every 60 seconds. Once the file updates, the script grabs it, unzips the data, uploads the products which contain WMO headers to the LDM software running the IDS|DDPLUS|EXP protocols. I then use the LDM to grab the data being injected into it and send the warnings to the Web site, and to feed *anyone* who wants it via the LDM. Remember, EMWIN is only a 9600 baud feed, and it only contains the most critical of information. You can learn exactly what comes across EMWIN by seeing this page, which has the complete data listing:

THE SITE: If you are using the LDM, request IDS|DDPLUS for text products, and EXP for image products, to the following site:

When you request IDS|DDPLUS, you'll get the products with standard WMO headers; there is no need to change your pqact.conf to accomodate the EMWIN feed, UNLESS you want the images on the EXP feed, which are typically delayed images from NWS web sites. NOTE: LDM 6.6.3 is absolutely recommended to get this feed successfully. Because of the "bursty" nature of this feed, LDM's 6.5 and before can miss a product as the feed starts back up after a delay. There may be 1-3 minutes where you get nothing, depending on the time of day and if there's no severe weather going on.

The UNIX-based bash script is freely available if you wish to do this locally. It will work on UNIX/Linux (I'm running it on Fedora Core), and I'll send you the script if you want it. It is very easy to integrate it into your NOAAport feed. You do have to turn the script on manually, which means that if NOAAport goes down, you have to know that (easy to tell), but you have to be at a machine to monitor your feed to see it happening.

So there it is. Nothing earth-shaking here, just a decent backup in case all heck breaks loose and NOAAport croaks. I hope you DON'T find it useful, as I hope the NOAAport feed always stays on! :-)


********************************************************************** ********* Gilbert Sebenste ******** (My opinions only!) ****** Staff Meteorologist, Northern Illinois University **** E-mail: sebenste@xxxxxxxxxxxxxxxxxxxxx *** web: http:// ** ********************************************************************** *********

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