Prognostic Meteorological Discussion
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FXUS10 KWNH 251613
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1113 AM EST THU DEC 25 2014

VALID DEC 25/1200 UTC THRU DEC 29/0000 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...

12Z MODEL EVALUATION...INCLUDING THE NAM AND GFS


...UPPER TROUGH DIGGING ACROSS THE INTERMOUNTAIN WEST/FOUR CORNERS
REGION THROUGH FRI...
...ENERGY EJECTING OUT ACROSS THE CENTRAL PLAINS AND UPPER MIDWEST
THROUGH SAT...

PREFERENCE: 12Z GFS
CONFIDENCE: AVERAGE

THE MODELS DEPICT A STRONG UPPER TROUGH DIGGING THROUGH THE
INTERMOUNTAIN WEST THROUGH FRI...WITH A PORTION OF THIS ENERGY
FORECAST TO EJECT EAST ACROSS THE CENTRAL PLAINS AND UPPER MIDWEST
THROUGH SAT. THIS ENERGY WILL FOSTER THE DEVELOPMENT OF A SURFACE
LOW THAT WILL CROSS FROM THE MID MS VALLEY TO THE GREAT LAKES
REGION THROUGH SAT. THERE IS NOT A LARGE AMOUNT OF SPREAD WITH THE
HEIGHT FALL DETAILS...BUT WITH THE SURFACE LOW...THE 00Z ECMWF AND
TO A LESSER EXTENT THE 00Z GEM ARE SLOWER THAN THE GLOBAL MODEL
CONSENSUS. THE TREND OVER THE LAST DAY OR SO HAS BEEN TO BE MORE
PROGRESSIVE WITH THIS ENERGY...AND THE 12Z GFS/12Z NAM AND 00Z
UKMET ARE RELATIVELY FASTER THAN THE ECMWF/GEM CAMP. THE 00Z ECENS
MEAN SUGGESTS THE 00Z ECMWF IS A TAD TOO SLOW AND BASED ON THE
OVERALL TRENDS TO BE MORE PROGRESSIVE AND COUPLED WITH THE 06Z
GEFS MEAN WHICH FAVORS THE MORE PROGRESSIVE CAMP...THE ECMWF AND
GEM SOLNS WILL BE DISCOUNTED. WILL PREFER THE 12Z GFS ATTM.


...SHORTWAVE ENERGY SHEARING OVER THE FOUR CORNERS REGION/SOUTHERN
PLAINS...

PREFERENCE: BLEND OF THE 12Z GFS/00Z ECMWF AND 00Z UKMET
CONFIDENCE: AVERAGE

SHORTWAVE ENERGY LEFT BEHIND OVER THE FOUR CORNERS REGION BY LATE
SAT WILL SHEAR EAST OUT ACROSS THE SOUTHERN PLAINS ON SUN. THE 12Z
NAM AND ESP THE 00Z GEM ARE THE SLOWEST/DEEPEST SOLNS. THE 00Z
ECMWF/00Z UKMET AND 12Z GFS ARE RELATIVELY MORE SHEARED/FLATTER
AND FASTER WHICH IS SUPPORTED BY THE LATEST GEFS MEAN AND ECENS
MEAN. THEREFORE...WILL PREFER A BLEND OF THE 12Z GFS/00Z ECMWF AND
00Z UKMET.


...SHORTWAVE TROUGH DIGGING TOWARD THE PACIFIC NORTHWEST ON SAT...

PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS INDICATE A SHORTWAVE TROUGH DIGGING SOUTHEAST FROM THE
GULF OF AK AND INTO SOUTHWEST BRITISH COLUMBIA AND THE PACIFIC
NORTHWEST BY LATER SAT. THE 12Z NAM AND 00Z UKMET ARE JUST A TAD
MORE PROGRESSIVE THAN THE 12Z GFS AND 00Z ECMWF. THE 00Z GEM
APPEARS TO BE TOO FLAT WITH THE SHORTWAVE. THE STRONGER MODEL
CLUSTERING AND ENSEMBLE SUPPORT WOULD FAVOR A BLEND OF THE 12Z GFS
AND 00Z ECMWF ATTM.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

ORRISON

$$




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