Prognostic Meteorological Discussion
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000
FXUS10 KWNH 271641
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1240 PM EDT WED AUG 27 2014

VALID AUG 27/1200 UTC THRU AUG 31/0000 UTC

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


12Z NAM/GFS MODEL EVALUATION...INCLUDING PRELIMINARY PREFERENCES

...UPPER TROUGH AND ASSOCIATED COLD FRONT CROSSING THE NORTHEAST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

OVERALL...THE 12Z NAM/GFS ARE IN GOOD AGREEMENT WITH THE 00Z
ECMWF/UKMET/CANADIAN GLOBAL WITH RESPECT TO THE TIMING/AMPLITUDE
OF THE 500 MB TROUGH AND ASSOCIATED SURFACE FRONT.

...UPPER-LEVEL TROUGH/LOW MOVING FROM THE ROCKIES IN THE PLAINS...
...SURFACE COLD FRONT DEVELOPING LATE WED IN THE LEE OF THE
CENTRAL ROCKIES...
...SURFACE LOW LIFTING INTO THE MIDWEST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THERE ARE NO SIGNIFICANT OUTLIERS AMONGST THE 12Z NAM/GFS AND THE
00Z ECMWF/UKMET/ECMWF WITH THE AFOREMENTIONED FEATURES.


...SHORTWAVE IMPULSE MOVING FROM THE PAC NW FRI MORNING TO THE
UPPER MIDWEST BY SAT EVENING...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: BELOW AVERAGE

MODELS ARE IN FAIRLY GOOD AGREEMENT WITH THIS FEATURE WITH SOME
MINOR TIMING/AMPLITUDE DIFFERENCES NEAR THE END OF THE PERIOD.

...EASTERLY WAVE ADVANCING WEST ALONG THE GULF COAST...

PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: AVERAGE

AS NOTED IN PREVIOUS RUNS...THE NAM IS MORE AMPLIFIED THAN THE
MODEL CONSENSUS AS THIS SYSTEM MOVES INTO SOUTH TX/NORTHERN MEX.

...WAVE LIFTING FROM THE CENTRAL GULF INTO THE LOWER MS VALLEY...

PREFERENCE: GFS/00Z ECMWF COMPROMISE
CONFIDENCE: BELOW AVERAGE

THE 00Z UKMET IS AMONG THE MORE AMPLIFIED MODELS AS THIS SYSTEM
LIFTS ALONG THE WESTERN EDGE OF THE RIDGE FROM THE CENTRAL GULF
COAST INTO THE LOWER MS VALLEY.  IT ALONG WITH THE 00Z CANADIAN
GLOBAL ALSO LIFTS THE SYSTEM FURTHER TO THE NORTH LATE IN THE
PERIOD.  IN CONTRAST...THE NAM OFFERS LITTLE EVIDENCE OF THIS
FEATURE AT ALL.  THE 00Z ECMWF IS A LITTLE MORE AMPLIFIED THAN THE
GFS...BUT BOTH SHOW THIS FEATURE LIFTING ACROSS THE CENTRAL GULF
COAST INTO THE LOWER MS VALLEY LATE IN THE PERIOD.


...DEEP TROUGH DIGGING INTO THE NORTHWEST BY FRI AND SAT...
...COLD FRONT PUSHING THROUGH THE NORTHWEST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THERE ARE NO SIGNIFICANT OUTLIERS AMONGST THE 12Z NAM/GFS AND THE
00Z ECMWF/UKMET/CANADIAN GLOBAL WITH THESE FEATURES.

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

PEREIRA


$$





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