970
FXUS10 KWNH 090434
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1134 PM EST SUN DEC 08 2019
VALID DEC 09/0000 UTC THRU DEC 12/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..EASTERN CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND FAVORING ECWMF THEN GFS IN BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE GLOBAL SCALE DEEP LATITUDE TROF IS TAKING A MORE PHASED SHAPE
CURRENTLY AS PRESENTED BY GOES-WV SUITE. THE MODEL GUIDANCE
APPEARS TO HAVE COME INTO STRONGER CONSENSUS WITH RESPECT TO THE
TIMING OF THE NORTHERN STREAM SHORTWAVE AND POINT WHERE THE
SOUTHERN STREAM SHORTWAVE DECOUPLE LATE MONDAY INTO TUES...AND
SHOW STRONG TIMING/AMPLITUDE AGREEMENT ALOFT WHICH TRANSLATES TO
SOLID AGREEMENT IN THE DEPTH/TRACK OF THE SURFACE WAVE AND COLD
FRONT. BY LATE TUESDAY, THOUGH THE 12Z CMC STARTS TO FALL OUT OF
TOLERANCE IN BOTH THE NORTHERN AND SOUTHERN STREAM. THE SOUTHERN
STREAM, IT IS A BIT STRONGER BUT ALSO EVOLVES INTO A MORE
COMPACT/DEEPER SOLUTION WHILE THE REMAINING SHEARED ENERGY SLIDES
THROUGH THE APPALACHIANS INTO THE NORTHEAST IN THE OTHER
SOLUTIONS. THE 00Z GFS AND 12Z ECMWF ARE IN FAIRLY SOLID
AGREEMENT WITH ONLY MODERATE DIFFERENCES NOTED IN QPF. THE 00Z
NAM SHOWS A BIT STRONGER INFLECTION IN THIS ENERGY LIFTING THROUGH
THE MID-ATLANTIC INTO THE NORTHEAST BY END OF DAY 3 WHICH IS
SOLID, BUT MAY BE TOO WET, ESPECIALLY GIVEN THE LIKELY DYNAMIC
COOLING, AND POTENTIALLY PRODUCING A BIT TOO MUCH SNOW...SO A
GFS/ECMWF SOLUTION IS GENERALLY MORE FAVORED BUT SOME LOCALIZED
INCLUSION OF THE UKMET/NAM MAY BE EMPLOYED IF DESIRED.
..WESTERN CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND FAVORING GFS/GEFS
CONFIDENCE: SLIGHTLY BELOW AVERAGE
IN THE WEST, A HIGHLY ELONGATED SHEAR ZONE/AXIS PRESSES EASTWARD
REACHING THE PACIFIC NORTHWEST MIDDAY TUESDAY. THE 00Z/NAM BOTH
CONTINUE TO BE SLIGHTLY FASTER IN SQUEEZING THE TROF AND THEREFORE
STRETCHING IT NW TO SE INTO TERRAIN...OPPOSED BY THE ECMWF (BEING
SLOWER WITH THE UPSTREAM EDGE), ROLLS THROUGH THE RIDGE MORE
COMPACT AND THEN INTO THE NORTHERN HIGH PLAINS A BIT FASTER.
PAIRED MORE WITH THE UKMET/CMC BUT BOTH ARE A BIT MORE SHARPER. A
SECONDARY SHORTWAVE/SPEED MAX OUT OF THE PACIFIC, QUICK ON THE
HEELS, AMPLIFIES ALONG THE CENTRAL WEST COAST AND FILLS OUT THE
BASE OF A PROGRESSIVE TROF TOWARD 12Z WED INTO THURSDAY.
TYPICALLY, THE ECMWF/ECENS MEAN ASSIMILATE THE WEST A BIT BETTER,
BUT THE EVOLUTION HERE SEEMS A BIT LESS METEOROLOGICALLY SOUND
GIVEN THE SHORTWAVE, SHAPE BREAKING THROUGH A TIGHT RIDGE THAT
WOULD BE BETTER SUPPORTED BY THE ORIENTATION OF TERRAIN NATURALLY.
SO WOULD BE OK WITH A GENERAL MODEL BLEND THOUGH, MASS FIELDS
WOULD SUGGEST/SUPPORT THE GFS/NAM THOUGH BY THURSDAY, THE TROF IS
NEARLY 60DM DEEPER THAN THE CMC/UKMET/ECMWF ACROSS THE WEST.
THIS DOES NOT HAVE MUCH SENSIBLE WEATHER DIFFERENCES THROUGH THE
END OF THE SHORT-RANGE PERIOD, SO WILL FAVOR A GFS/ECMWF/NAM BLEND
TO BEST REPRESENT THE SYSTEM(S), BUT WITH IN A LOWER
PREDICTABILITY REGIME, CONFIDENCE IS SLIGHTLY BELOW AVERAGE.
ADDITIONALLY, THIS BLEND IS NOT LIKELY TO BE FAVORED THROUGH DAY
4/5 GIVEN THIS HEIGHT/STRENGTH DIFFERENCE IN THE SOUTHERN
STREAM...PLEASE REFER TO WPC PMDEPD FOR ADDITIONAL INFORMATION.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
GALLINA
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