988
FXUS10 KWNH 300640
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
139 AM EST SAT NOV 30 2019
VALID NOV 30/0000 UTC THRU DEC 03/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CLOSED LOW CROSSING THE INTERMOUNTAIN WEST/PLAINS
..SYSTEM REACHING THE MID-ATLANTIC/NEW ENGLAND BY MON/TUES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND...THROUGH 60 HOURS
NON-NAM BLEND...LED BY 00Z GFS/ECMWF...AFTER 60 HOURS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE DEEP LAYERED CLOSED LOW CURRENTLY MOVING THROUGH THE
INTERMOUNTAIN WEST WILL REORGANIZE AND DEEPEN ACROSS THE HIGH
PLAINS AND MIDWEST ON SATURDAY ALONG WITH DEVELOPMENT OF A NOTABLY
STRONG SURFACE LOW. THEREAFTER, THE SYSTEM ADVANCES EAST ACROSS
THE OH VALLEY AND REACHES THE MID-ATLANTIC REGION BY MONDAY, WITH
THE ATTENDANT AREA OF SURFACE LOW PRESSURE REDEVELOPING ALONG THE
MID-ATLANTIC COAST AND LIFTING NORTHEAST NEAR SOUTHEAST NEW
ENGLAND BY EARLY TUESDAY. THE 00Z CMC APPEARS TO BE A TAD TOO WEAK
WITH THE SYSTEM AS IT CROSSES THE PLAINS AND MIDWEST, BUT DOES
COME INTO BETTER AGREEMENT WITH THE MODEL CONSENSUS AS IT ARRIVES
ALONG THE EAST COAST. THE 00Z NAM BY MONDAY AND TUESDAY APPEARS TO
BE A LITTLE TOO DEEP WITH ITS MID-LEVEL LOW CENTER OVER THE
MID-ATLANTIC AND SOUTHEAST NEW ENGLAND. MEANWHILE, TOWARD THE END
OF THE PERIOD, THE 00Z UKMET MAY BE A TAD SLOW. THE SPREAD SEEN
EARLIER BETWEEN THE GFS AND ECMWF LATE IN THE PERIOD HAS NARROWED
CONSIDERABLY WITH THE 00Z CYCLE, AND THERE IS GOOD ENSEMBLE
SUPPORT FOR THIS CLUSTER WITH RESPECT TO BOTH THE LOW AND
MID-LEVEL LOW PLACEMENTS. THE LATEST GEFS MEAN AND ECENS MEAN
SUPPORT THE GFS/ECMWF CAMP. SO, BASED ON THE LATEST MODEL TRENDS
AND CLUSTERING, A NON-CMC BLEND WILL BE PREFERRED THROUGH 60
HOURS, FOLLOWED BY A NON-NAM BLEND LED BY THE 00Z GFS/ECMWF AFTER
60 HOURS.
..UPPER LOW APPROACHING THE WEST COAST BY SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GEFS MEAN/12Z ECENS MEAN
CONFIDENCE: AVERAGE
BY SUNDAY, A NEW CLOSED LOW WILL BE EVOLVING OFFSHORE OF THE WEST
COAST, INCLUDING A SEPARATE CENTER OVER THE NORTHWEST U.S. WHICH
BREAKS AWAY AND PIVOTS OFFSHORE THE WEST COAST. THERE WILL BE SOME
BINARY INTERACTION BETWEEN THE TWO CENTERS, WITH MOST OF THE
GUIDANCE FAVORING A GRADUAL CONSOLIDATION OF THE TWO SYSTEMS. MOST
OF THE GUIDANCE SUGGESTS THIS CONSOLIDATED SYSTEM THEN DROPPING
SOUTH OFFSHORE CA THROUGH MONDAY AND TUESDAY. THE 00Z NAM/GFS AND
00Z CMC APPEAR TO BE POSSIBLY PLACING THE MID-LEVEL LOW CENTER TOO
FAR NORTH BY THE END OF THE PERIOD, AS THE 00Z UKMET/ECMWF AND THE
LATEST GEFS MEAN AND ECENS MEAN FAVOR THE SYSTEM FOCUSING A LITTLE
BIT FARTHER SOUTH. WILL FAVOR THE LATTER CAMP WITH AN EMPHASIS ON
THE ENSEMBLE MEANS.
..SHORTWAVE APPROACHING THE NORTHERN PLAINS/UPPER MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS BRING A NORTHERN STREAM SHORTWAVE SOUTHEAST ACROSS
PORTIONS OF THE NORTHERN PLAINS AND UPPER MIDWEST BY THE END OF
THE PERIOD ALONG WITH A NEW COLD FRONT. THERE IS SUFFICIENT MODEL
MASS FIELD AGREEMENT WITH THIS SYSTEM TO FAVOR A GENERAL MODEL
BLEND AT THIS POINT.
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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