Prognostic Meteorological Discussion
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000
FXUS10 KWNH 250642
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 AM EDT MON JUL 25 2016

VALID JUL 25/0000 UTC THRU JUL 28/1200 UTC

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

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


...WEAK UPPER LEVEL LOW CROSSING THE NORTHERN GULF OF MEXICO...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A WEAK UPPER LOW CROSSING THE FLORIDA PENINSULA WILL CONTINUE
TRACKING WESTWARD THROUGH TUES...TRAVERSING THE GULF OF MEXICO
BEFORE REACHING THE TX COAST BY TUES NIGHT. THE 00Z NAM CONTINUES
TO BE A TAD DEEPER THAN THE MODEL CONSENSUS...SO WILL AGAIN PREFER
A NON-NAM COMPROMISE.


...TROUGH OVER THE UPPER MIDWEST REACHING NEW ENGLAND TUES
MORNING...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A PROGRESSIVE MID LEVEL TROUGH WILL TRACK ACROSS THE UPPER GREAT
LAKES THROUGH MON MORNING AND THEN REACHING QUEBEC CANADA ON TUES.
THIS WILL RESULT IN A SURFACE COLD FRONT ADVANCING ACROSS THE
GREAT LAKES AND NORTHEAST STATES. THE 00Z NAM REMAINS SLIGHTLY
MORE AMPLIFIED THAN THE WELL-CLUSTERED GLOBAL MODELS. WILL PREFER
A NON-NAM CONSENSUS WITH THIS SYSTEM.


...LOW-AMPLITUDE SHORTWAVES CROSSING THE NORTHERN PLAINS/MIDWEST
THROUGH MIDWEEK...
...BROAD TROUGH AMPLIFICATION OVER THE PLAINS THROUGH MIDWEEK...
...WEAK SURFACE WAVE DEVELOPMENT OVER THE MIDWEST...

PREFERENCE: BLEND OF THE 00Z GFS AND 00Z ECMWF
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE GUIDANCE SHOWS A SERIES OF GENERALLY LOW-AMPLITUDE SHORTWAVES
EMBEDDED WITHIN THE WESTERLIES NORTH OF THE SUBTROPICAL
RIDGE...CROSSING THE MIDWEST TUES AND WED. THIS GRADUALLY LEADS TO
SOME BROADER SCALE TROUGH AMPLIFICATION OVER THE PLAINS BY THURS.
OVERALL...THE 00Z NAM IS MORE AMPLIFIED WITH THE SHORTWAVE DETAILS
OVER THE REGION...AND THIS LEADS TO THE NAM HAVE A SOMEWHAT
STRONGER SURFACE WAVE ADVANCING UP ALONG A FRONT DRAPED OVER THE
MIDWEST. THE 00Z UKMET BY COMPARISON FOR MOST OF THE PERIOD
APPEARS TOO WEAK WITH ITS ENERGY. THE 00Z GFS AND 00Z ECMWF HAVE
BETTER AGREEMENT ON THE LARGER SCALE...BUT THEIR ARE SOME TIMING
DIFFERENCES NOTED WITH THE SHORTWAVE IMPULSES...WITH THE 00Z GFS A
LITTLE MORE PROGRESSIVE AND THE 00Z ECMWF SLOWER. THE GEFS MEAN
AND ECENS MEAN SUPPORT THEIR RESPECTIVE DETERMINISTIC
SOLUTIONS...AND SO WILL SUGGEST A COMPROMISE BETWEEN THE GFS AND
ECMWF AT THIS POINT.


...TROUGH OVER THE PACIFIC NORTHWEST...

PREFERENCE: NON-GFS CONSENSUS
CONFIDENCE: AVERAGE

THE MODELS HAVE A SHORTWAVE TROUGH GRADUALLY CROSSING THE
NORTHWEST TUES AND WED. SOME RELATIVELY MINOR DIFFERENCES WITH
TIMING/DEPTH EXIST WITH THIS SYSTEM...ALTHOUGH THE 00Z GFS DOES
GENERALLY SUGGEST A MORE AMPLIFIED SYSTEM THAN THE MODEL
CONSENSUS. WILL PREFER A NON-GFS COMPROMISE AS A RESULT FOR THE
TIME BEING.

ORRISON

...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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