Prognostic Meteorological Discussion
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000
FXUS10 KWNH 291625
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1225 PM EDT FRI MAY 29 2015

VALID MAY 29/1200 UTC THRU JUN 02/0000 UTC

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

12Z NAM/GFS EVALUATION AND PRELIMINARY PREFERENCES

SHORTWAVE TROUGH AND ASSOCIATED COLD FRONT OVER THE
NORTHERN-CENTRAL PLAINS...

PREFERENCE: EQUAL BLEND NAM OR GFS
CONFIDENCE: ABOVE AVERAGE

ALTHOUGH LARGE-SCALE WISE...MODEL AGREEMENT IS GOOD WITH THIS
SYSTEM...ITS INTERACTION WITH THE MCV FARTHER SOUTH WARRANTS AN
EMPHASIS UPON THE NAM AND GFS FOR GUIDANCE COMPARED TO THE 00Z
ECMWF...WHICH POORLY DEPICTS THE MCV ALONG WITH ITS INTERACTION.

SHORTWAVE TROUGH OVER THE MIDDLE-LOWER MS VALLEY...

PREFERENCE: EQUAL BLEND NAM/GFS
CONFIDENCE: ABOVE AVERAGE

THE NAM AND GFS SHOW SEEMINGLY ACCURATE INITIALIZATION OF THIS
SYSTEM COMPARED TO OLDER GUIDANCE INCLUDING A DEEPER SURFACE LOW
AND STRONGER FRONT IN ADVANCE OF IT...THUS SUPPORTING AN
INTERMEDIATE SOLUTION INVOLVING THE 2 SOLUTIONS. THE 00Z ECMWF
SHOWS POOR ALIGNMENT WITH THE MCV AND THUS IS NOT RECOMMENDED.

SHORTWAVE TROUGH OVER THE SOUTHERN ROCKIES...

PREFERENCE: GFS
CONFIDENCE: ABOVE AVERAGE

THE NAM AND GFS ALLOW PORTIONS OF THE TROUGH TO SLOW DOWN AND
POSSIBLY BREAK OFF FROM THE WESTERLIES ACROSS THE MIDDLE/LOWER MS
VALLEY COMPARED TO THE 00Z ECMWF.  GIVEN MORE RECENT
INITIALIZATION AND TRENDS DEPICTING A LARGER AND MORE CONSOLIDATED
REMNANT CIRCULATION...THEIR SLOWER SOLUTIONS SEEM MORE REASONABLE
THAN THE FASTER AND WEAKER SOLUTIONS.  HOWEVER...THE NAM IS NEARLY
AN OUTLIER BY LATE MONDAY...WITH THE GFS BETTER SUPPORTED BY THE
ENSEMBLE MEMBERS.  THUS...RECOMMEND THE GFS.

SHORTWAVE TROUGH REACHING THE PACIFIC NORTHWEST SUN-MON...

PREFERENCE: NAM OR GFS OR ECMWF
CONFIDENCE: AVERAGE

MODELS SHOW GOOD LARGE SCALE AGREEMENT WITH AVERAGE SPREAD BY DAY
3.

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

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

JAMES

$$





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