[Met_help] Using MET with fcst_lead >= 100 h

[John Halley Gotway]

John,

Regarding WPP, I really don't think that you'll have a problem.  I'm
currently working on a project with folks from NOAA where we're creating
forecasts out to 114 hours and are running the most recently released
version of WPP just fine.  You would only potentially have an issue if you
were running your forecasts out > 255 hours.

Regarding issues with MET, you're probably correct.  I think this would
come up in your use of the MODE-Analysis and STAT-Analysis tools.  That's
the place you'd be specifying the forecast lead time in the config file or
 on the command line.  I believe it would be a pretty easy fix involving
changes to the "timestring_to_sec" routine in the file
METv2.0/lib/vx_cal/time_strings.cc.

However, before making any changes, I'd like to do some testing to make
sure it really is a problem.  And once I verify that, I'll work on a fix. 
If I isolate the problem and come up with a fix, I'd post it to the MET
website and update the package of bug fixes.

I'll let you know how it pans out.  Please let me know if, in your use of
MET, you find another place where it's a problem to have forecast hours >
99.

Thanks,
John

> Hello John,
>
> Thanks for the prompt response. Perhaps I had briefly come across the
> WPP email and thought it was actually related to MET...
>
> I believe - according to the user manual - that MET allows the user to
> specify forecast lead time as HH[MMSS], which seems to me to prevent
> leads times > 99h. Am I mistaken?
>
> Regarding WPP...I intend to verify precip accumulation in MET for a
> year-long series of 5.5-day forecasts that overlap at the beginning of
> each forecast run to avoid spin-up problems. It's a pretty standard way
> of generating year-long WRF simulations. However, that means that I will
> be applying WPP to WRF forecasts with forecast lead times of 12 h to 132
> h. I hadn't anticipated any problems with WPP, unfortunately. I have a
> vague memory that someone had come up with a fix for the long-lead time
> problem, but I'm not sure. Would you be able to investigate the status
> for me?
>
> Thanks.
>
> John
>
> On 12/23/09 2:51 PM, John Halley Gotway wrote:
>> John,
>>
>> I looked back through the old MET-Help emails and couldn't find anything
>> that would explain a problem of using fcst_lead>= 100 hours.  So I'm not
>> aware of a problem with that.  I did find one email
>> related to this but I believe that was due to an incorrectly packed GRIB
>> file, not a problem in MET itself.
>>
>> However, there are some issues in WPP (WRF-PostProcessor) for
>> accumulated precip when the forecast lead time extends beyond 255 hours.
>>  The time value of 255+ overflows the single byte that's
>> allocated in the GRIB record to store that time info.  This is mostly an
>> issue for accumulated precip since you have to store 2 times in the GRIB
>> record - accumulation starting and ending times.  I'm
>> not sure of the status of this issue, but if you run across it, I can
>> look into it more.
>>
>> I'd say, proceed with trying to use MET to verify forecasts>= 100 hours.
>>  And if you run into any problems, just let us know through
>> met_help at ucar.edu.
>>
>> If you haven't already done so, I would suggest retrieving the latest
>> set of bug fixes for METv2.0 from:
>> http://www.dtcenter.org/met/users/support/known_issues/METv2.0/index.php
>>
>> Hope that helps,
>> John Halley Gotway
>> johnhg at ucar.edu
>>
>> John Henderson wrote:
>>
>>> Hello,
>>>
>>> When first I installed WRF-MET I believe I saw a discussion somewhere
>>> about how to apply WRF-MET to forecasts that require a fcst_lead of at
>>> least 100 h, however, I can't seem to find it now. Can you point me in
>>> the right direction?
>>>
>>> Thanks.
>>>
>>> John Henderson
>>> AER, Inc.
>>>
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>