Prognostic Meteorological Discussion
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000
FXUS10 KWNH 220414
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1213 AM EDT FRI AUG 22 2014

VALID AUG 22/0000 UTC THRU AUG 25/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING THE NAM AND GFS


...UPPER TROUGHING MOVING FROM THE GREAT LAKES ACROSS THE
NORTHEAST...
...COLD FRONT SINKING SWD THROUGH THE EAST COAST STATES...

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

THE 00Z NAM AGAIN INSISTS ON STRONGER HEIGHT FALLS DIGGING SWD
DOWN ALONG THE EAST COAST OVER THE NEXT COUPLE OF DAYS AS COMPARED
TO THE GLOBAL MODEL CONSENSUS. THE NAM AS A RESULT GENERALLY SENDS
A COLD FRONT A LITTLE MORE QUICKLY SWD DOWN THE ERN SEABOARD AS
WELL AND INTO THE SOUTHEAST THROUGH THE WEEKEND. THE STRONGER
MODEL CLUSTERING ATTM FAVORS A 00Z GFS AND 12Z ECMWF BLEND AND
THIS WILL BE THE PREFERENCE.


...WEAKENING MID LEVEL DISTURBANCE LIFTING NEWD FROM THE
SOUTHWEST...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM IS SOMEWHAT OF A STRONGER OUTLIER WITH THE ENERGY THAT
EJECTS NEWD OUT OF THE SOUTHWEST OVER THE NEXT COUPLE OF DAYS AND
AHEAD OF THE LARGER SCALE UPPER TROUGH/CLOSED LOW THAT DIGS SEWD
INTO THE NWRN U.S. BY THIS WEEKEND. WILL PREFER A NON-NAM
CONSENSUS WITH THIS ENERGY AS IT SHEARS NEWD.


...UPPER TROUGHING/CLOSED LOW DIGGING INTO THE WESTERN U.S. FOR
FRI AND SAT...
...LOW PRESSURE DEVELOPING OVER THE CENTRAL/NORTHERN PLAINS...

PREFERENCE: BLEND OF THE 12Z ECMWF AND 12Z GEM
CONFIDENCE: AVERAGE

A DEEP UPR TROUGH AND ASSOCD CLOSED LOW SHOULD EVOLVE OVER THE
WESTERN U.S. OVER THE NEXT COUPLE OF DAYS BEFORE THEN ADVANCING
ENEWD INTO THE NRN HIGH PLAINS AND INTO SRN CANADA BY EARLY NEXT
WEEK. THIS COUPLED WITH THE SHEARING ENERGY OVER THE SOUTHWEST
WILL HELP DRIVE SFC LOW PRESSURE INITIALLY OVER THE CNTRL PLAINS
AND THEN NEWD UP THROUGH THE NRN PLAINS AND UPR MS VLY. THE 00Z
NAM BECOMES TOO DEEP ALOFT IN TIME AND DRIVE SFC LOW PRESSURE TOO
FAR BACK TO THE NORTHWEST...RELATIVE TO ALL THE GLOBAL MODELS. THE
00Z GFS GRADUALLY BECOMES TOO PROGRESSIVE IT APPEARS...AS THE 12Z
UKMET AND ESP THE 12Z GEM AND 12Z ECMWF ARE SLOWER. THE 12Z ECMWF
AND 12Z GEM HAVE THE STRONGEST ENSEMBLE SUPPORT INVOLVING THE GEFS
MEAN AND ECENS MEAN. A BLEND OF THE ECMWF AND GEM WILL BE
PREFERRED.


...ADDITIONAL SHORTWAVE ENERGY DIGGING INTO THE NORTHWEST BY SUN
AND MON...

PREFERENCE: 12Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS INDICATE THAT THERE WILL BE ADDITIONAL SHORTWAVE ENERGY
DIGGING INTO THE NORTHWEST ON SUN AND MON IN BEHIND THE EXITING
DEEP TROUGH. OVERALL...THE 12Z UKMET IS THE WEAKEST SOLN WITH THE
00Z NAM AND 12Z GEM THE STRONGEST. WILL PREFER THE 12Z ECMWF ATTM
GIVEN BETTER ENSEMBLE SUPPORT FROM THE LATEST SREF MEAN AND ECENS
MEAN.


...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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