277
FXUS10 KWNH 020503
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1203 AM EST THU JAN 02 2020
VALID JAN 02/0000 UTC THRU JAN 05/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..UPPER LOW OVER MEXICO SHEARING TO THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
THE MODELS SHOW GOOD AGREEMENT IN LIFTING THE SOUTHERN STREAM
CLOSED LOW OVER MEXICO OFF TO THE NORTHEAST OVER THE NEXT 24 HOURS
WITH THE SYSTEM SHEARING OUT ACROSS THE LOWER RIO GRANDE VALLEY AS
IT BECOME EMBEDDED IN DEEP LAYER SOUTHWEST FLOW AHEAD OF AN
AMPLIFYING TROUGH OVER THE SOUTHERN HIGH PLAINS. A GENERAL MODEL
BLEND WILL BE PREFERRED.
...AMPLIFYING LONGWAVE TROUGH ACROSS THE CENTRAL U.S.
..SURFACE LOW FROM THE LOWER MS VALLEY TO THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/12Z ECMWF/18Z GEFS/12Z ECENS BLEND
CONFIDENCE: AVERAGE
A SPLIT FLOW UPPER TROUGH WITH SEVERAL SMALL SCALE SHORTWAVE
IMPULSES WILL EJECT OUT ACROSS THE PLAINS GOING THROUGH THE END OF
THE WEEK, WITH INITIALLY THE DOMINANT AMPLIFICATION OCCURRING DOWN
OVER THE SOUTHERN HIGH PLAINS. HOWEVER, BY LATE FRIDAY, AS
MULTIPLE PIECES IN THE NORTHERN STREAM WILL DIG DOWN ACROSS THE
MIDWEST AND LEAD TO A MORE DOMINANT NORTHERN STREAM TROUGH AND
CLOSED LOW EVOLUTION WHICH WILL PICK UP THE SOUTHERN STREAM
ENERGY. THIS WILL LEAD TO SURFACE LOW OVER THE LOWER MS VALLEY
WHICH WILL LIFT NORTHEAST TOWARD THE OH VALLEY BY SATURDAY. THIS
SYSTEM WILL CROSS THE NORTHERN MID-ATLANTIC BY SATURDAY EVENING
WITH LOW PRESSURE REDEVELOPING NEAR SOUTHEAST NEW ENGLAND BY EARLY
SUNDAY. THE 00Z GFS HAS TRENDED CLOSER TO THE 12Z ECMWF AND
GEFS/ECENS MEAN CLUSTER REGARDING THE LOW AND AND MID-LEVEL TROUGH
EVOLUTION. TOWARD THE END OF THE PERIOD, THE 12Z CMC IS LIKELY TOO
PROGRESSIVE AND TOO FAR SOUTH WITH THE LOW CENTER, WITH THE 00Z
NAM/12Z UKMET SOLUTIONS PERHAPS CLOSER TO THE GFS/ECMWF CLUSTER,
BUT JUST A TAD MORE PROGRESSIVE. THE PREFERENCE WITH THE ENERGY
FROM THE PLAINS TO THE EASY COAST WILL TOWARD A BLEND OF THE
GFS/ECMWF AND ENSEMBLE MEANS.
..SHORTWAVE TROUGH/LOW IMPACTING THE PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-ECMWF BLEND
CONFIDENCE: AVERAGE
THERE REMAIN SOME TIMING DIFFERENCES WITH RESPECT TO ENERGY
APPROACHING VANCOUVER ISLAND AND THE PACIFIC NORTHWEST THURSDAY
AND FRIDAY. MODEL AGREEMENT IS ACTUALLY RATHER GOOD WITH THE FIRST
SHORTWAVE AND ATTENDANT SURFACE LOW THAT AIMS FOR CENTRAL BRITISH
COLUMBIA BY LATE THURSDAY WHICH WILL HELP DRIVE A WARM FRONT UP
ACROSS WESTERN WA THURSDAY NIGHT. AS THIS SYSTEM, FAST UPSTREAM
PACIFIC FLOW WILL DRIVE ANOTHER SHORTWAVE AND STRONG SURFACE LOW
EASTWARD TO NEAR THE NORTHERN END OF VANCOUVER ISLAND BY FRIDAY
NIGHT. A COLD FRONT ASSOCIATED WITH THIS WILL THEN CROSS THE
PACIFIC NORTHWEST BY EARLY SATURDAY. THE 12Z ECMWF IS A TAD SOUTH
OF THE MODEL CONSENSUS WITH THE SECOND SYSTEM, WITH THE REMAINING
GUIDANCE CLUSTERED FARTHER NORTH AND SUPPORTED BY THE LATEST GEFS
MEAN AND ECENS MEAN. WILL PREFER A NON-ECMWF CONSENSUS FOR THE
TIME BEING.
..SPLIT FLOW TROUGH NEAR THE PACIFIC NORTHWEST BY SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 18Z GEFS MEAN/12Z ECENS MEAN
CONFIDENCE: AVERAGE
THE MODELS SHOW A NEW SPLIT FLOW UPPER TROUGH AND ATTENDANT FRONT
APPROACHING THE PACIFIC NORTHWEST BY SUNDAY. THE 00Z NAM/GFS AND
12Z UKMET ARE A BIT FASTER THAN THE 12Z CMC/ECMWF SOLUTIONS WITH
THE NORTHERN PORTION OF THE TROUGH. MEANWHILE, THE 12Z CMC AND 12Z
UKMET ARE SLOW OUTLIERS WITH THE SOUTHERN PORTION OF THE TROUGH.
FOR NOW, A BLEND OF THE ENSEMBLE MEANS WILL BE PREFERRED SINCE
THIS CLUSTER APPEARS TO HAVE A REASONABLE HANDLE ON BOTH PORTIONS
OF THE SPLIT FLOW TROUGH.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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