New LDM server for EMWIN-only feed

Sat Apr 28 11:19:21 MDT 2007

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 media...in 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

5. EMWIN

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:

http://www.weather.gov/emwin/windat.htm

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

www.ehs.niu.edu

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

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Gilbert Sebenste                                                     ********
(My opinions only!)                                                  ******
Staff Meteorologist, Northern Illinois University                      ****
E-mail: sebenste at weather.admin.niu.edu                                  ***
web: http://weather.admin.niu.edu                                      **
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