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Re: MVFR



Mike,

The dcmetr program does not decode XVFR from a METAR coded observation,
so you will not find it in the metar.pack file.

Instead, the SFPARM display or listing of XVFR is created from the
values
of Ceiling and Visibility that are stored in your data set. The gemlib
routine
$GEMPAK/source/gemlib/pr/prxvfr.f 
determines the more restrictive of the conditions as documented by
NCEP's 
developers.

For a ceiling of 3000 ft (eg 30 hundreds of feet), and a visibility of >
5 miles, the
computed XVFR should be "2" based on the criteria of  CEIL <=30.

If you have specific instances of the actual data not producing this
result, I'd
be happy to look at the metar observation. Be sure to look at the data
values
of ceiling to verify the condition is as you state.

Steve Chiswell
Unidata User Support




On Mon, 2007-03-12 at 10:47 -0500, Mike Bender wrote:
> Steve,
> 
> There appears to be an incorrect dcmetr decoding of the aviation flying 
> categories.  VFR is being decoded for visibilities of 5 statute miles 
> and ceilings are above 3000 feet.  This is clearly MVFR (VIS 3 to 5 
> miles, VFR is > 5 miles).  I thought it might be something in the 
> metar.pack file, but there is no reference in the file for the XVFR 
> output.  Am I missing something? 
> 
> Mike
> 
> 
-- 
Steve Chiswell <address@hidden>
Unidata