[gradsusr] Incorrect Winds from NCEP NAM file

[Wesley Ebisuzaki]

Bill,

1)      When I plot the CONUS nam grids at NCEP , the 250mb winds are 
westerly and consistent with the height field.
2)      Don's grib files do say that the winds are grid relative and 
need to be rotated (LCCR).
3)      The NCEP operations shouldn't be changing the wind rotation.

Wesley

Don,

    There is a mistake in your Florida NAM files.  Do you know where you 
got them from?
There seems to have been a mistake made in creating the regional subset.

          Wesley



Bill Bua wrote:
> Jennifer et al --
>
> That makes perfect sense.  At 12 UTC on 18 October 2011, the NAM went 
> from the rotated Arakawa E-grid to the Arakawa B-grid.  So LLCR would 
> not be appropriate to use anymore.  It's still lambert conformal, so 
> the LLC is correct.
>
> Bill
>
> On 10/27/2011 7:53 PM, Jennifer Adams wrote:
>> I think you need to change "lccr" to "lcc" in your PDEF entry. 
>> --Jennifer
>>
>> On Oct 27, 2011, at 6:33 PM, Donald Van Dyke wrote:
>>
>>> Hello,
>>>
>>> I'm not sure if this is a grib2 file problem or a GrADS problem, but 
>>> if I try to plot the winds from the attached NAM grib2 file from 
>>> NCEP, the wind is plotted incorrectly.  I am using g2ctl.pl with no 
>>> flags and gribmap -i to create the .ctl and .idx files.  In the 
>>> GrADS script, I am using simple commands such as
>>>
>>> "set lev 250"
>>> "d mag(ugrdprs,vgrdprs)*1.943844449"
>>> "d skip(ugrdprs*1.943844449,2,2);skip(vgrdprs*1.943844449,2,2)"
>>>
>>> The image created is attached along with an image from NCEP showing 
>>> what the winds should have looked like over my area in the Florida 
>>> Panhandle.  They're obviously not northerly.  I am currently using 
>>> grads.2.0.a9.  I have also attached the grib2 file as well as the 
>>> .ctl file and .idx file I created with g2ctl.pl and gribmap.  Thanks.
>>>
>>> -Don
>>>
>>>
>>>
>>> <nam_namer_000_250_wnd_ht.gif><0.ctl><nam.t00z.awip3200.tm00.grib2><nam.t00z.awip3200.tm00.grib2.idx><nam250wind-0.png>_______________________________________________
>>> gradsusr mailing list
>>> gradsusr at gradsusr.org <mailto:gradsusr at gradsusr.org>
>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>> --
>> Jennifer M. Adams
>> IGES/COLA
>> 4041 Powder Mill Road, Suite 302
>> Calverton, MD 20705
>> jma at cola.iges.org <mailto:jma at cola.iges.org>
>>
>>
>>
>>
>>
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>>     
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