Wednesday, September 21, 2011

A new radar is born!

Today, the newest radar in the NEXRAD system began publicly transmitting its data.  This radar is known as the Langley Hill radar (KLGX) and it's located in Grays Harbor County in western Washington.  Here's a sample reflectivity image from this evening:
As you can see, the radar's position on the coast affords us the new ability to watch storm systems and rainfall before they reach the coast--giving us advance warning of the structure and strength of precipitation.  This is going to be amazingly helpful both to forecasters and anyone curious when the rain in Seattle is going to start.

The KLGX radar is also equipped as a dual-polarimetric radar--one of the first in the country to receive this new technology.  I'll do some future blog posts talking about what dual-polarimetric radar means, but for now, those who already know will be happy to see that the variables seem to be coming in nicely.  Here's an example cross-pol correlation coefficient plot from the same time.
You can view live data yourself from the radar online currently through the University of Washington's radar loops at:

Also, for those people who use the Gibson Ridge Level II or Level II analyst program, here's the modifications I needed to make to add this radar:

1)  In the directory where Windows installed GR (usually something like C:\Program Files\GRLevelX\GR2Analyst), you can edit either of two files (depending if they exist or not)--radars.gis or curstomradars.gis (It may not let you save changes to the file since it's in the Program Files directory.  I find I have to copy the file to my desktop, edit it, save it, then copy it back into the GR2Analyst directory for it to work).

2) In either the radars.gis or customradars.gis file, add the following line
"klgx, ksew, 47.1169, -124.1066, 73, 1, WA, Langley Hill"
(Those may not be the official values for the location, but it's the closest I could find.)
This line gives the following information--the radar ID, the WFO that runs the radar (KSEW--Seattle, in this case), the latitude, longitude, elevation, some random flag, the radar is in the state of Washington, and its official name is "Langley Hill".
Save the file and, if needed, copy it back into the GR2Analyst directory.

3) Open up GR2(Analyst) and go to File, Configure Polling. Highlight the address for your level II radar source in the text box, then click the "Refresh" button.  This makes Gibson Ridge confirm that your online data source actually includes the KLGX radar.  Then, click Ok.

4) Navigate to the radar site and start polling for radar data.  It should start downloading the level II data and displaying images.  At least, I use the Iowa State level II source and they have the data flowing.

That's it!  You should be able to see data from the new radar, now, too.  Enjoy watching our rain tonight and tomorrow...

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