808
FXUS10 KWNH 020656
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
156 AM EST MON DEC 02 2019
VALID DEC 02/0000 UTC THRU DEC 05/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CLOSED LOW IMPACTING THE MID-ATLANTIC/NEW ENGLAND
..SURFACE LOW PRESSURE LIFTING OFFSHORE THE NORTHEAST
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PREFERENCE: BLEND OF THE 00Z NAM/HREF...THROUGH 36 HOURS
BLEND OF THE 00Z NAM/GFS/ECMWF...AFTER 36 HOURS
CONFIDENCE: ABOVE AVERAGE
DIFFERENCES WITH THIS SYSTEM ARE RELATIVELY MINOR ALOFT, REGARDING
THE 500/700 MB CLOSED LOW POSITIONS AND STRENGTH. THE UKMET WHICH
HAD BEEN A BIT SLOWER AND FARTHER WEST WITH ITS CLOSED LOW AND
SURFACE REFLECTION AS THE SYSTEM LIFTS UP OFFSHORE NEW ENGLAND AND
THROUGH THE GULF OF MAINE ON TUESDAY, HAS TRENDED A LITTLE FARTHER
EAST, BUT REMAINS ON THE WEST SIDE OF THE MODEL SPREAD. THE 00Z
GFS IS ALSO ON THE WEST SIDE OF THE MODEL SPREAD AND RATHER CLOSE
TO THE UKMET. THE 00Z CMC AND 00Z ECMWF TRENDED A BIT FARTHER EAST
AND ARE REASONABLY CLOSE TO THE 00Z NAM AND HIRES HREF GUIDANCE
PER THE 00Z ARW/ARW2 AND 00Z NMMB GOING THROUGH 36 HOURS. AFTER 36
HOURS, THE GLOBAL MODELS DO COME INTO BETTER AGREEMENT AS THE
SYSTEM EXITS THE GULF OF MAINE AND LIFTS ACROSS SOUTHEAST CANADA.
ACCOUNTING FOR A BIT OF AN EASTWARD SHIFT/TREND IN THE LOW
PRESSURE TRACK WITH THE LATEST HIRES MODEL SUITE, AND WITH THE
GLOBAL MODELS OVERALL FOLLOWING SUIT, THE LATEST MODEL PREFERENCE
WILL BE TOWARD A NAM/HREF BLEND THROUGH ABOUT 36 HOURS, AND THEN A
BLEND OF THE 00Z NAM/GFS AND 00Z ECMWF THEREAFTER GIVEN FAVORABLE
CLUSTERING AND SUPPORT FROM THE 00Z GEFS MEAN.
..UPPER LOW OFFSHORE THE WEST COAST THROUGH TUESDAY
..ENERGY THEN CROSSING THE SOUTHWEST ON WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 36 HOURS
NON-UKMET BLEND...AFTER 36 HOURS
CONFIDENCE: ABOVE AVERAGE
THERE IS RATHER GOOD AGREEMENT WITH THE EVOLUTION OF THE UPPER LOW
OFFSHORE THE WEST COAST THROUGH ABOUT 36 HOURS, BUT THEREAFTER THE
00Z UKMET TENDS TO BE A LITTLE SLOWER AND SOUTH OF THE MULTI-MODEL
CONSENSUS AS THE SYSTEM APPROACHES THE SOUTHWEST AND ADVANCES
INLAND. WILL PREFER A GENERAL MODEL BLEND THROUGH 36 HOURS, AND A
NON-UKMET BLEND THEREAFTER.
..SHORTWAVE CROSSING THE NORTHERN PLAINS/UPPER MIDWEST MONDAY
..AMPLIFYING ACROSS THE OH VALLEY/NORTHEAST TUESDAY/WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 48 HOURS
BLEND OF THE 00Z GFS/ECMWF...AFTER 48 HOURS
CONFIDENCE: ABOVE AVERAGE
THE MODELS BRING A NORTHERN STREAM SHORTWAVE SOUTHEAST ACROSS
PORTIONS OF THE NORTHERN PLAINS AND UPPER MIDWEST ON MONDAY AND
THEN DROP IT DOWN ACROSS THE OH VALLEY AND NORTHEAST THROUGH
TUESDAY AND WEDNESDAY. THE GUIDANCE IS IN GOOD AGREEMENT WITH THIS
EVOLUTION THROUGH 48 HOURS, BUT THEREAFTER THE 00Z CMC AND 00Z
UKMET EDGE STRONGER THAN THE REMAINING GUIDANCE AS THE TROUGH
AMPLIFIES IN ACROSS THE NORTHEAST. THE UKMET ALSO BECOMES A BIT
SLOWER THAN THE OTHER MODELS WITH ITS TIMING. ON THE OTHER HAND,
THE 00Z NAM BECOMES THE MOST PROGRESSIVE SOLUTION WHICH IS IN PART
RELATED TO ITS HANDLING OF UPSTREAM SHORTWAVE ENERGY OVER
SOUTH-CENTRAL CANADA. THE BETTER MODEL CLUSTERING AND ENSEMBLE
SUPPORT RESIDES MORE WITH THE 00Z GFS AND 00Z ECMWF, AND SO A
BLEND OF THESE SOLUTIONS WILL BE PREFERRED AFTER 48 HOURS. A
GENERAL MODEL BLEND WILL BE PREFERRED PRIOR TO THIS.
..WEAK SHORTWAVE/LOW CLIPPING THE NORTHERN PLAINS WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z UKMET/ECMWF AND 12Z ECENS MEAN
CONFIDENCE: BELOW AVERAGE
THE MODELS SUPPORT A WEAK SHORTWAVE AND ASSOCIATED SURFACE
LOW/FRONT CLIPPING THE NORTHERN PLAINS LATE WEDNESDAY AND THROUGH
EARLY THURSDAY. THERE IS CONSIDERABLE MODEL SPREAD WITH THIS
FEATURE AS THE 00Z NAM IS A FASTER AND YET DEEPER OUTLIER COMPARED
TO THE GLOBAL MODELS. MEANWHILE, THE 00Z CMC GLOBAL IS THE SLOWEST
SOLUTION. THE 00Z GFS, 00Z UKMET AND 00Z ECMWF ALL SPLIT THE
DIFFERENCE WITH TIMING, BUT AT THE SURFACE THERE IS LATITUDINAL
SPREAD WITH THE SURFACE LOW. THE ECMWF AND UKMET ARE NORTH OF THE
GFS, WITH THE 12Z ECENS MEAN SUPPORTING THE ECMWF/UKMET CAMP. THE
00Z GEFS MEAN HAS TRENDED TOWARD THE ECMWF/UKMET CLUSTER OVERALL,
AND SO BASED ON THE LATEST TRENDS, A BLEND OF THE 00Z UKMET/ECMWF
AND 12Z ECENS MEAN WILL BE PREFERRED WITH THIS SYSTEM. CONFIDENCE
REMAINS LIMITED.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
ORRISON
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