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20050615: 20050615: strange new station in central Nebraska!

Clint,

Canada still has some stations reporting in pseudo-sao using 3 character ID's,
so some 3 character decoding is still done.

Back in SAO days, Canadian stations reported in Celsius, and US in Fahrenheit.
The decoding will use the country code in the station table for 3 letter IDs 
to determine if the temperatures are Fahrenheit or Celsius. In this case, since 
the MHN match was for an "NE US" state/country code, it assumed the temps were 
Fahrenheit though since it wasn't an SAO that shouldn't be the case. 

This all goes back to the improper station location. Placing the K infront of 
Mullen will prevent the 3 character decoding. Elsewise, tracking down the 
location 
for CMHN would also work.  METARs are always reported in Celsius (or tenths of 
Celsius in RMK).

Chiz


Steve Chiswell
Unidata User Support


>From: Clint Rowe <address@hidden>
>Organization: University of Nebraska Geosciences
>Keywords: 200506151829.j5FITWZu018390

>Chiz,
>Okay, but you didn't answer the part about why the temperatures
>plotted for temperature and dewpoint are the Celsius values reported
>in the metar, while all the US stations plot the correct Fahrenheit
>values.  If I list today's obs and the raw metars, things don't 
>match at all.  The Fahrenheit temps are close to (but certainly not 
>exactly) the values reported (as Celsius) in the metars.
>
> GEMPAK-SFLIST>l
> SFFILE   = metar
> AREA     = @mhn
> DATTIM   = all
> SFPARM   = slat;slon;tmpf;dwpf;tmpc;dwpc
> OUTPUT   = t
> IDNTYP   = stid
> GEMPAK-SFLIST>r
> PARM = SLAT;SLON;TMPF;DWPF;TMPC;DWPC
> 
>    STN    YYMMDD/HHMM      SLAT     SLON     TMPF     DWPF     TMPC    
>DWPC
>    MHN    050615/0000     42.05  -101.07    19.94    19.94    -6.70   
>-6.70
>    MHN    050615/0100     42.05  -101.07    19.94    19.94    -6.70   
>-6.70
>    MHN    050615/0200     42.05  -101.07    19.04    19.04    -7.20   
>-7.20
>    MHN    050615/0300     42.05  -101.07    17.96    17.96    -7.80   
>-7.80
>    MHN    050615/0400     42.05  -101.07    17.96    17.96    -7.80   
>-7.80
>    MHN    050615/0500     42.05  -101.07    17.06    17.06    -8.30   
>-8.30
>    MHN    050615/0600     42.05  -101.07    15.98    15.98    -8.90   
>-8.90
>    MHN    050615/0700     42.05  -101.07    15.98    15.98    -8.90   
>-8.90
>    MHN    050615/0800     42.05  -101.07    15.08    15.08    -9.40   
>-9.40
>    MHN    050615/0900     42.05  -101.07    15.08    15.08    -9.40   
>-9.40
>    MHN    050615/1000     42.05  -101.07    15.98    15.98    -8.90   
>-8.90
>    MHN    050615/1100     42.05  -101.07    15.98    15.98    -8.90   
>-8.90
>    MHN    050615/1200     42.05  -101.07    15.98    15.08    -8.90   
>-9.40
>    MHN    050615/1300     42.05  -101.07    15.08    15.08    -9.40   
>-9.40
>    MHN    050615/1400     42.05  -101.07    15.98    15.98    -8.90   
>-8.90
>    MHN    050615/1500     42.05  -101.07    15.98    15.98    -8.90   
>-8.90
>    MHN    050615/1700     42.05  -101.07    15.08    15.08    -9.40   
>-9.40
> 
> 
> Parameters requested: SFFILE,AREA,DATTIM,SFPARM,OUTPUT,IDNTYP.
>
>
>and the corresponding raw metars:
>CMHN 150000Z AUTO 15008KT 20/20 RMK AO1 T02030202 50002=
>CMHN 150100Z AUTO 15006KT 20/20 RMK AO1 T01970195=
>CMHN 150200Z AUTO 17006KT 19/19 RMK AO1 T01900187=
>CMHN 150300Z AUTO 12002KT 18/18 RMK AO1 T01840182=
>CMHN 150400Z AUTO 12004KT 18/18 RMK AO1 T01770177=
>CMHN 150500Z AUTO 13007KT 17/17 RMK AO1 T01690169=
>CMHN 150600Z AUTO 14006KT 16/16 RMK AO1 T01620160=
>CMHN 150700Z AUTO 15005KT 16/16 RMK AO1 T01570156=
>CMHN 150800Z AUTO 09002KT 15/15 RMK AO1 PAST HR P0009 T01530153 50024=
>CMHN 150900Z AUTO 12003KT 15/15 RMK AO1 PAST HR P0007 T01540154 50042=
>CMHN 151000Z AUTO 12002KT 16/16 RMK AO1 PAST HR P0002 T01570157 50048=
>CMHN 151100Z AUTO 12009KT 16/16 RMK AO1 T01550155 50048=
>CMHN 151200Z AUTO 12004KT 16/15 RMK AO1 PAST HR P0002 T01580153 50054=
>CMHN 151300Z AUTO 11003KT 15/15 RMK AO1 PAST HR P0002 T01540154 50006=
>CMHN 151400Z AUTO 14005KT 16/16 RMK AO1 PAST HR P0003 T01590159 50014=
>CMHN 151500Z AUTO 04002KT 16/16 RMK AO1 T01630163 50014=
>CMHN 151600Z AUTO 11002KT 16/16 RMK AO1 T01600159 50014=
>CMHN 151700Z AUTO 14003KT 15/15 RMK AO1 PAST HR P0001 T01540150 50016=
>
>
>On Wed, 2005-06-15 at 12:11, Unidata Support wrote:
>> Clint,
>> 
>> Change MHN to KMHN in the station table so that CMHN won't match on it.
>> Unless you want to use that station table to decode old SAO format
>> data with the 3 character ID's, the 4 character METAR match will always work
> .
>> The search always tries the 4 character ID first, and then if
>> not found, it will try to match on the 3 character ID if it is
>> a Cxxx or Kxxx identifier- which was really useful when transitioning
>> to METAR from SAO.
>> 
>> You will end up with CMHN stored as an extra station (lat/lon will be -9999.
>> until the table is updated or the file is updated with SFSTNS.
>> 
>> Steve Chiswell
>> Unidata User Support
>> 
>> >From: Clint Rowe <address@hidden>
>> >Organization: University of Nebraska Geosciences
>> >Keywords: 200506151600.j5FG0UZu017428
>> 
>> >
>> >--=-0Hok+ZmohNaQCBkY2Ta1
>> >Content-Type: text/plain
>> >Content-Transfer-Encoding: 7bit
>> >
>> >Chiz,
>> >
>> >Recently, a "new" station started getting plotted in Nebraska, but
>> >it's obviously not a Nebraskan station as it's consistently much 
>> >colder and often exhibits an extreme wind shift compared to nearby 
>> >stations.  Check out MHN in west-central Nebraska (just WNW of TIF)
>> >on the attached surface plot from this morning.  MHN (Mullen, NE)
>> >hasn't reported in ages (since modernization, I think), so I looked 
>> >in our raw METARs and found the following METAR for CMHN (which 
>> >isn't in any of the gempak station tables and can't be found at
>> >http://www.nws.noaa.gov/tg/siteloc.shtml.  Regardless, it appears 
>> >to be a Canadian station (probably in southeastern Ontario or
>> >Quebec, given the weather).
>> >
>> >
>> >149 
>> >SACN82 KWBC 151408^M^M
>> >METAR CMBR 151400Z AUTO 07007KT 18/18 RMK AO1 T01810181=
>> >METAR CMCT 151400Z AUTO 12008KT 19/18 RMK AO1 T01880180=
>> >METAR CMCW 151400Z AUTO 15006KT 20/19 RMK AO1 T02020191=
>> >METAR CMHN 151400Z AUTO 14005KT 16/16 RMK AO1 PAST HR P0003
>> >T01590159 50014=
>> >METAR CMRI 151400Z AUTO 08009KT 16/16 RMK AO1 8012 SLP985
>> >T01600160 50046=
>> >METAR CMSB 151400Z AUTO 13006KT 18/17 RMK AO1 T01790165 50002=
>> >
>> >In the same raw file, KMHN reports
>> >KMHN NIL
>> >
>> >
>> >So, how to deal with this?  I could delete Mullen from the station
>> >table so it doesn't get plotted (quick and dirty, "solves" the
>> >problem -- but certainly not elegant).  I could try more to figure
>> >out where this station is and add it to the station table, but I 
>> >notice that Canadian stations only have three-letter IDs in
>> >sfstns.tbl (could it be added as CMHN instead of MHN?).
>> >
>> >Also, I'm curious as to why the temperature and dewpoint are plotted
>> >as tmpc/dwpc instead of the requested tmpf/dwpf?  Are US stations
>> >decoded and stored as degrees Fahrenheit while non-US stations are
>> >stored as degrees Celsius and gempak doesn't think it needs to 
>> >convert them for display?
>> >
>> >Clint
>> >-- 
>> >====================================================================
>> >Clinton M. Rowe
>> >Associate Professor
>> >Meteorology/Climatology Program                  phone:(402)472-1946
>> >Department of Geosciences                          fax:(402)472-4917
>> >University of Nebraska-Lincoln                        address@hidden
>> >
>> --
>> ****************************************************************************
>> Unidata User Support                                    UCAR Unidata Program
>> (303)497-8643                                                  P.O. Box 3000
>> address@hidden                                   Boulder, CO 80307
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>-- 
>====================================================================
>Clinton M. Rowe
>Associate Professor
>Meteorology/Climatology Program                  phone:(402)472-1946
>Department of Geosciences                          fax:(402)472-4917
>University of Nebraska-Lincoln                        address@hidden
>
--
NOTE: All email exchanges with Unidata User Support are recorded in the
Unidata inquiry tracking system and then made publicly available
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