501
FXUS10 KWNH 030449
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1148 PM EST THU JAN 02 2020
VALID JAN 03/0000 UTC THRU JAN 06/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..AMPLIFYING LONGWAVE TROUGH ACROSS THE CENTRAL U.S.
..SURFACE LOW FROM THE LOWER MS VALLEY TO THE NORTHEAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/18Z GEFS/12Z ECENS/12Z CMC BLEND
CONFIDENCE: AVERAGE
A SPLIT FLOW UPPER TROUGH 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, MULTIPLE PIECES OF ENERGY 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 INTERACT WITH THE SOUTHERN STREAM ENERGY. THIS WILL LEAD TO
SURFACE LOW DEVELOPMENT 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 SOUTH OF LONG ISLAND BY EARLY SUNDAY. THE MODELS HAVE
OVERALL TRENDED WEAKER COMPARED TO LAST NIGHT, AND DO NOT SUGGEST
AS PHASED OF A SYSTEM IMPACTING NEW ENGLAND. THE 00Z NAM OVERALL
BECOMES A BIT MORE PROGRESSIVE WITH THE SYSTEM COMPARED TO THE
GLOBAL MODELS. THE 00Z GFS AND 12Z CMC ARE CLUSTERED JUST A LITTLE
NORTH OF THE 12Z ECMWF, BUT CLOSE TO THE CONSENSUS OF THE LATEST
GEFS MEAN AND ECENS MEAN. THE 12Z UKMET IS CLOSE TO THE CONSENSUS,
BUT GRADUALLY OUTRUNS IT AS THE LOW CENTER PULLS AWAY FROM THE
NORTHEAST. WILL RECOMMEND A BLEND GFS/CMC AND ENSEMBLE MEANS AS A
RESULT.
..SHORTWAVE TROUGH/LOW IMPACTING THE PACIFIC NORTHWEST
..ENERGY EJECTING OUT ACROSS THE PLAINS/MIDWEST BY SAT/SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS ARE IN GOOD AGREEMENT WITH THE DETAILS OF FAST UPSTREAM
PACIFIC FLOW AIMING TOWARD THE PACIFIC NORTHWEST WHICH 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. THIS SYSTEM WILL ADVANCE VERY QUICKLY DOWNSTREAM
ACROSS THE INTERMOUNTAIN WEST AND ACROSS THE NORTHERN PLAINS AND
MIDWEST SATURDAY AND SUNDAY BEFORE IMPACTING THE GREAT LAKES ON
MONDAY. THE 12Z CMC GRADUALLY BECOMES A BIT WEAKER WITH THE LOW
CENTER THAT CROSSES SOUTHERN CANADA COMPARED TO THE REMAINING
GUIDANCE, AND SO A NON-CMC BLEND WILL BE PREFERRED.
..SPLIT FLOW TROUGH NEAR THE PACIFIC NORTHWEST BY SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
THE MODELS SHOW A NEW SPLIT FLOW UPPER TROUGH AND ATTENDANT FRONT
APPROACHING THE PACIFIC NORTHWEST BY SUNDAY. THE 00Z NAM/GFS
SOLUTIONS AND 12Z UKMET SOLUTIONS ARE A TAD FASTER THAN THE 12Z
CMC/ECMWF SOLUTIONS WITH THE SYSTEM. HOWEVER, COLLECTIVELY ALL OF
THE SOLUTIONS ARE QUITE PROGRESSIVE WITH THE LARGE SCALE FLOW.
SOME THE ENERGY WITH THIS WILL SPILL OUT ACROSS THE NORTHERN HIGH
PLAINS BY EARLY MONDAY WITH A WEAK LEESIDE LOW DEVELOPING EAST OF
THE ROCKIES. GIVEN THE MODEST MASS FIELD SPREAD WITH THIS SYSTEM,
A GENERAL MODEL BLEND WILL BE PREFERRED.
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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