Prognostic Meteorological Discussion
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000
FXUS10 KWNH 251633
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1232 PM EDT MON JUL 25 2016

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

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

12Z NAM/GFS EVALUATION...INCLUDING PRELIMINARY PREFERENCES AND
FORECAST CONFIDENCE


...UPPER LEVEL LOW CROSSING THE NORTHERN GULF OF MEXICO TUE/WED...

PREFERENCE: NON-NAM BLEND
CONFIDENCE: ABOVE AVERAGE

THE 12Z NAM CONTINUES TO BE A BIT DEEPER AND FURTHER WEST WITH THE
UPPER LOW AS IT REACHES THE TX COAST TUE INTO WED. THE 12Z GFS IS
CLOSER TO THE CONSENSUS...AND IT BETTER SUPPORTED BY THE 00Z ECMWF
ENSEMBLE MEAN/00Z GEFS. GIVEN THE GOOD MODEL AGREEMENT...A NON NAM
BLEND IS PREFERRED.


...TROUGH OVER THE UPPER MIDWEST REACHING NEW ENGLAND TUE...

PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 12Z NAM AND 12Z GFS WERE CLOSE TO THE CONSENSUS WITH THE SHORT
WAVE TRACKING ACROSS THE UPPER GREAT LAKES THROUGH QUEBEC INTO NEW
ENGLAND TUE...AS WELL AS THE SURFACE FRONT IT PUSHES TO THE COAST.
GIVEN THE GOOD MODEL AGREEMENT...A GENERAL MODEL BLEND IS
PREFERRED.


...DEVELOPING MID LEVEL TROUGH OVER THE PLAINS INTO THE MIDWEST
TUE INTO THU...

PREFERENCE: 12Z GFS/00Z ECMWF BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE 12Z NAM IS CLOSE TO THE CONSENSUS WITH THE SHORT WAVE TRACKING
OUT OF THE NORTHERN
ROCKIES/NORTHERN PLAINS ON THE SOUTHERN EDGE OF THE WESTERLIES
THAT DEVELOPS INTO A MID LEVEL TROUGH OVER THE MIDWEST/MID MS
VALLEY. HOWEVER...THE 12Z NAM BECOMES FASTER THAN THE CONSENSUS BY
THE END OF THE PERIOD. THE 12Z GFS IS ALSO CLOSE TO THE CONSENSUS
THROUGH WED... BUT ENDS UP FASTER THAN THE 00Z ECMWF BY 29/00Z.

THE FASTER 12Z GFS TIMING IS SUPPORTED BY THE 00Z GEFS MEAN
POSITION (WHILE THE SLOWER 00Z ECMWF IS SUPPORTED BY ITS ENSEMBLE
MEAN POSITION). GIVEN THE DIFFERENCES IN TIMING AT THE END OF THE
PERIOD...BLENDING THE TWO CAMPS (12Z GFS/00Z ECMWF) SHOULD PROVIDE
THE BEST SOLUTION...AND THIS BLEND IS PREFERRED.


...MID LEVEL TROUGH OVER THE PACIFIC NORTHWEST TUE INTO WED...

PREFERENCE: NON-GFS CONSENSUS
CONFIDENCE: AVERAGE

THE 12Z NAM IS CLOSE TO THE CONSENSUS WITH THE TIMING OF THE MID
LEVEL TROUGH ACROSS THE PACIFIC NORTHWEST/BRITISH COLUMBIA TUE
INTO WED. THE 12Z GFS CONTINUES ITS DEEPER TREND WITH THIS
FEATURE...SO IT WAS AGAIN LEFT OUT OF THE PREFERRED MODEL BLEND.

HAYES

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

$$





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