110
FXUS10 KWNH 010457
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1156 PM EST SAT NOV 30 2019
VALID DEC 01/0000 UTC THRU DEC 04/1200 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: GENERAL MODEL BLEND...THROUGH 48 HOURS
00Z NAM/GFS AND 12Z ECMWF BLEND...AFTER 48 HOURS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE DEEP LAYERED CLOSED LOW CROSSING THE MIDWEST WILL ADVANCE
STEADILY EAST ACROSS THE OH VALLEY ON SUNDAY AND REACH THE
MID-ATLANTIC REGION BY MONDAY. THE ATTENDANT AREA OF LOW PRESSURE
WILL LIFT ACROSS THE UPPER OH VALLEY AND THE LOWER GREAT LAKES
REGION, WITH SECONDARY CYCLOPEDIAS OCCURRING NEAR THE DELMARVA BY
LATE SUNDAY WHICH WILL THEN LIFT NORTHEAST AND DEEPEN NEAR
SOUTHEAST NEW ENGLAND THROUGH MONDAY. BY TUESDAY, THE SYSTEM
SHOULD EXIT ACROSS THE GULF OF MAINE AND REACH CANADIAN MARITIMES.
THE GUIDANCE IS IN RATHER GOOD AGREEMENT THROUGH ABOUT 48 HOURS,
BUT THEREAFTER, THE 00Z GFS TENDS TO FOCUS IS LOW PRESSURE A
LITTLE FARTHER OFFSHORE OF NEW ENGLAND COMPARED TO THE 00Z NAM AND
12Z ECMWF. THE 12Z CMC TENDS TO BE A BIT FARTHER OFFSHORE AS WELL,
BUT THE 12Z UKMET IS FARTHER WEST AND LEFT OF THE NAM/ECMWF CAMP
WITH THE PRIMARY LOW CENTER. TOWARD THE END OF THE PERIOD, THE GFS
HAS TRENDED A LITTLE MORE FAVORABLY TOWARD THE NAM/ECMWF CLUSTER
WITH THIS CYCLE. SO, BASED ON THE LATEST TRENDS AND CLUSTERING, A
GENERAL MODEL BLEND WILL BE PREFERRED THROUGH 48 HOURS, FOLLOWED
BY A NAM/GFS AND ECMWF BLEND THEREAFTER.
..UPPER LOW APPROACHING THE WEST COAST BY SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS/18Z GEFS MEAN AND 12Z ECENS MEAN
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
ON 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 THE GUIDANCE
FAVORING A CONSOLIDATION OF THE TWO SYSTEMS OFFSHORE OF CALIFORNIA
BY MONDAY EVENING. THE SYSTEM IS EXPECTED TO DROP SOUTH THROUGH
TUESDAY AND THEN BEGIN TO ADVANCE SOUTHEAST TOWARD SOUTHERN
CALIFORNIA BY EARLY WEDNESDAY. THE 12Z CMC DOES NOT DROP THE
CLOSED LOW AS FAR SOUTH AS THE REMAINING GUIDANCE, AND BY THE END
OF THE PERIOD, THE CMC IS ALSO A BIT QUICKER TO EDGE THE SYSTEM
TOWARD SOUTHERN CALIFORNIA. THE 00Z NAM AND 12Z ECMWF ARE BOTH ON
THE SOUTHWEST EDGE OF THE DETERMINISTIC MODEL SPREAD, AND A LITTLE
SOUTHWEST OF THE LATEST GEFS MEAN AND ECENS MEAN WHICH BOTH ARE
SUPPORTIVE OF THE 00Z GFS. WILL FAVOR THE GFS-LED CONSENSUS AND
THE ENSEMBLE MEANS WITH THIS SYSTEM FOR THE TIME BEING.
..SHORTWAVE APPROACHING THE NORTHERN PLAINS/UPPER MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 48 HOURS
NON-UKMET BLEND...AFTER 48 HOURS
CONFIDENCE: ABOVE AVERAGE
THE MODELS BRING A NORTHERN STREAM SHORTWAVE SOUTHEAST ACROSS
PORTIONS OF THE NORTHERN PLAINS AND UPPER MIDWEST BY MONDAY AND
THEN DROP IT DOWN ACROSS THE OH VALLEY THROUGH TUESDAY. THE
GUIDANCE IS IN GOOD AGREEMENT THROUGH 48 HOURS, BUT THEREAFTER THE
12Z UKMET BEGINS TO OUTRUN THE REMAINING GUIDANCE WITH THE TIMING
OF ITS HEIGHT FALLS. WILL PREFER GENERAL MODEL BLEND THROUGH 48
HOURS, AND A NON-UKMET BLEND THEREAFTER.
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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