Prognostic Meteorological Discussion
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000
FXUS10 KWNH 230627
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
226 AM EDT SAT AUG 23 2014

VALID AUG 23/0000 UTC THRU AUG 26/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/GEM AND ECMWF


...UPPER TROUGHING MOVING THROUGH THE NORTHEAST...
...COLD FRONT SINKING SWD THROUGH THE EAST COAST STATES...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE DETAILS OF THE
TROUGH EXITING THE NORTHEAST OVER THE NEXT COUPLE OF DAYS. A
GENERAL MODEL COMPROMISE WILL BE PREFERRED BASED ON THE LARGER
SCALE AGREEMENT.


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

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE NAM HAS COME INTO BETTER AGREEMENT WITH THE OTHER MODELS WITH
THE DETAILS OF THE EXITING SRN STREAM SHORTWAVE TROUGH OVER THE
SOUTHWEST. A GENERAL MODEL COMPROMISE WILL BE PREFERRED.


...UPPER TROUGHING/CLOSED LOW ADVANCING THROUGH THE WEST THROUGH
SAT...
...SURFACE LOW MOVING THROUGH THE NORTHERN PLAINS AND INTO
CANADA...

PREFERENCE: BLEND OF THE 00Z GEM AND 00Z ECMWF
CONFIDENCE: AVERAGE

THE MODELS HAVE COME INTO BETTER AGREEMENT WITH THE EVOLUTION OF
THE DEEP TROUGH/CLOSED LOW THAT WILL BE EXITING THE WESTERN U.S.
OVER THE NEXT COUPLE OF DAYS AND TRAVERSING THE NRN PLAINS AND SRN
CANADA. ALL OF THE MODELS INDICATE THAT SFC LOW PRESSURE
DEVELOPING OVER THE CNTRL PLAINS ATTM WILL LIFT NNEWD THROUGH THE
PERIOD AND INTENSIFY WHILE MOVING INTO SRN CANADA BY SUN AND MON.
THE 00Z NAM AT TIMES APPEARS A LITTLE SLOW TO LIFT ITS LOW CENTER
NWD THROUGH THE NRN PLAINS...WHEREAS THE 00Z GFS IS NOTED TO BE
TUCKING ITS SFC LOW PRESSURE AREA A LITTLE TOO FAR BACK TO THE
WEST. THE 00Z GFS BECOMES SLOW IN TIME TO ADVANCE THE ENERGY ALOFT
EASTWARD ACROSS SRN CANADA. THE 00Z UKMET HAS TRENDED A BIT MORE
PROGRESSIVE...AND APPEARS OVERALL TO BE A BIT TOO PROGRESSIVE. THE
00Z GEM AND 00Z ECMWF ARE VERY CLUSTERED IN THE MIDDLE OF THE
OVERALL MODEL SUITE...AND A BLEND OF THESE TWO SOLNS WILL BE
PREFERRED.


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

PREFERENCE: BLEND OF THE 00Z GEM AND 00Z ECMWF
CONFIDENCE: AVERAGE

THE 00Z NAM IS THE STRONGEST SOLN WITH THE SHORTWAVE ENERGY THAT
AMPLIFIES OVER THE WEST BY MON AND TUES. THE 00Z UKMET MEANWHILE
SEEMS TO BE DROPPING ENERGY TOO FAR SOUTH THROUGH THE GREAT BASIN.
THE 00Z ECMWF AND 00Z GEM DID TREND A TAD STRONGER WITH THEIR
HEIGHT FALLS AND IT WOULD APPEAR NOW THAT THE 00Z GFS IS A
RELATIVELY WEAK OUTLIER. THE STRONGER MODEL CLUSTERING FAVORS A
BLEND OF THE 00Z ECMWF AND 00Z GEM AND THAT WILL BE THE PREFERENCE.


...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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