148
FXUS10 KWNH 281705
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1204 PM EST THU NOV 28 2019
VALID NOV 28/1200 UTC THRU DEC 02/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND FORECAST
CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CLOSED LOW CROSSING THE INTERMOUNTAIN WEST/PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM AND 00Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE 12Z GFS HAS BEEN TRENDED TOWARD THE PREFERRED MODEL CONSENSUS,
BUT IT REMAINS STRONGER AND INITIALLY A BIT FARTHER WEST WITH ITS
LOW LEVEL LOW THAT FORMS IN THE CENTRAL HIGH PLAINS FRIDAY NIGHT.
THE RESULT IS FOR SIGNIFICANTLY WARMER AIR FROM THE GFS IN THE LOW
LEVELS TO BE DRAWN NORTHWARD INTO THE NORTH-CENTRAL U.S. FRIDAY
NIGHT THROUGH SATURDAY. THE ECMWF MEAN AS WELL AS THE ECMWF HAVE
BEEN FAIRLY CONSISTENT WITH SURFACE AND 850 MB LOW POSITIONS OVER
THEIR PAST 4 12/00Z CYCLES. THE STRENGTH OF THE 12Z NAM COULD BE A
BIT WEAK BUT WHEN BLENDED WITH THE STRONGER 00Z ECMWF, A FAVORABLE
BLEND IS REACHED. THIS BLEND APPLIES TO POSITION AS WELL WITH THE
00Z ECMWF'S SURFACE LOW A BIT TOWARD THE NORTH SIDE OF THE LATEST
MODEL SPREAD. THE 00Z UKMET APPEARS TOO WEAK WHILE THE 00Z CMC
POSITION IS OFF FROM THE PREFERRED CONSENSUS. THIS BLEND APPLIES
THROUGH SUNDAY EVENING AS THE STORM SYSTEM NEARS THE EAST COAST
WITH SECONDARY LOW DEVELOPMENT ALONG THE NORTHERN MID-ATLANTIC
COAST.
..UPPER LOW APPROACHING THE WEST COAST BY SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE
BY SUNDAY, A NEW CLOSED LOW WILL BE EVOLVING OFFSHORE OF THE WEST
COAST ALONG WITH LOW PRESSURE AT THE SURFACE. THE 00Z CMC AND 00Z
UKMET BOTH APPEAR TO BE A TAD TOO WEAK WITH THIS SYSTEM AS WELL AS
DISPLACED FROM THE FAVORABLE ENSEMBLE MEAN POSITIONS. THE 12Z NAM
APPEARS TO BE DISPLACED TOO FAR WEST ON SUNDAY WITH THE 00Z ECMWF
CLOSER TO THE COAST. THE 12Z GFS SPLITS THE DIFFERENCE BUT LIES
CLOSER TO THE NAM POSITION. THE GEFS AND ECMWF MEANS SUPPORT A
MIDDLE GROUND, BETWEEN THE 12Z GFS AND 00Z ECMWF CONCERNING THE
500 MB LOW. REGARDING COLD FRONTAL TIMING, THE 12Z NAM IS SLOWEST
WITH THE 00Z ECMWF TOWARD THE FASTER SIDE. A BLEND OF THE 00Z
ECMWF WITH THE SLIGHTLY SLOWER 12Z GFS IS PREFERRED OVER THE
SLOWER 12Z NAM GIVEN DIFFERENCES IN POSITION IN THE 700-500 MB
LOW.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
OTTO
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