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20050429: Help getting Precip Grids



>From: Jennie Moody <address@hidden>
>Organization: UVa
>Keywords: 200504292036.j3TKajP3024271 ldm-mcidas NNEXRAD DPA decoding

Hi Jennie,

This will have to be a short reply as I am writing it from my hotel balcony
in Madrid, Spain while accessing the Internet through an open wireless
and flaky wireless connection somewhere in the city (the hotel does not
have a broadband connection).

>Hello support (Tom, Chis, Jeff, whomever)....
>Its been awhile since I asked any questions, its been awhile since I have 
>had time to focus on things mcidas/unidata, etc.
>
>Anyway, I recently had a question from a colleague.  He is trying to access 
>the digital precipitation array (radar estimated hourly precip grids) and 
>want to know if I can grab it with the ldm.

Yes, they are in the NNEXRAD IDD feed.

>Actually, he is working with 
>David Legates from Deleware, and since we have an ldm/McIDAS running and 
>have worked with grids from the HRS feed in the ldm, I guess they thought I 
>might be able to access these data more readily than the folks at Delaware. 
>I did get on-line and searched the archives for messages on the DPA, and 
>saw the recent questions that David asked (this was quick and helpful). 
>So, I guess I should have access to the DPA grids through the HRS 
>feed....

Nope, through the NNEXRAD feed.

>but, I am only running the following in my pqact:
>
>
>># Entries for McIDAS-XCD decoders
>> DDPLUS|IDS      ^.*     PIPE
>>         xcd_run DDS
>> HRS     ^.*     PIPE
>>         xcd_run HRS
>
>So, first question:  is there a McIDAS-XCD decoder to read the HRS feed of 
>the NEXRAD Level III DPA grids?

There is no McIDAS-XCD or Unidata ldm-mcidas decoder for the NNEXRAD DPA
data.  I figured that if interest every got high enough for the products
I would add one to ldm-mcidas.  So far, the interest has been limited,
but it appears to be picking up.

>If so, how do I find these grids (I looked 
>through the NOGRIB.CFG file (historically, a source of much confusion in my 
>brain) and don't see entries for anything other than model grids).
>
>If my xcd-decoders are not getting this from the HRS stream, then even if I 
>am not running gempak, it should be possilbe to run a gribtonc to 
>locate/save the DPA grids in the HRS datastream for a selected set of 
>stations and save them in netcdf format, right?

I believe that Chiz has already answered you on this one.

>I know that these guys have written some of their own software to read and 
>process DPA files, and they apparently recently lost the access they had to 
>these grids through some commercial provider.  I haven't been able to 
>contact the guy who wrote the software that reads the DPA grids, but I am 
>assuming that he (or I) can read the NETCDF files and get what he needs.

If they hace their own "decoders", they should be able to use the products
being sent in NNEXRAD.  All they would have to do is add the appropriate
pqact.conf action to file the products where they want them.

>Second question, any possibility that these grids are available through an 
ADDE server so I could pull them up and view them in McIDAS, that might be 
>helpful (though its not necessary at all).

No, sorry.  It sounds like I should revisit the DPA data access.

>Finally, third question, since I haven't been able to identify why the 
>previous source that these guys had for these grids went away, please let 
>me know if I am chasing a chimera (ie., is it possible that the DPA grids 
>are no longer being sent out on NOAAPort??).

They are.

>Hope this is all straight forward.
>
>Hey, in a separate note, I have FINALLY installed and tried out the IDV, 
>have had a couple of enthusiastic undergraduates trying to learn it.  I 
>hope to attend the McIDAS and IDV workshops this summer (if I can get some 
>funding from my Department), and would like to get back up to snuff with 
>things unidata before I teach a new course (new for UVA) on weather 
>forecasting this fall.

Sounds great.  It will be nice to see you in Boulder again!

>Happy Friday to all my Unidata friends.
>Be well,

Got to run; the network connection is hit and miss, so I am worried that
if I stay on too long, I will lose this reply :-(

Great to hear from you!

Cheers,

Tom
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