Prognostic Meteorological Discussion
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000
FXUS10 KWNH 241624
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1223 PM EDT SUN JUL 24 2016

VALID JUL 24/1200 UTC THRU JUL 28/0000 UTC

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

12Z MODEL EVALUATION - INCLUDING THE NAM/GFS


***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 TUESDAY, TRAVERSING THE GULF OF MEXICO
BEFORE REACHING THE TEXAS COAST BY TUESDAY NIGHT.  THE 12Z NAM HAS
LOWER OVERALL 500MB HEIGHTS THAN THE MODEL CONSENSUS, ALONG WITH
ITS PREVIOUS RUNS, WITH THE REMAINING MODELS RATHER WELL
CLUSTERED.  THEREFORE A NON-NAM COMPROMISE IS RECOMMENDED WITH
THIS FEATURE.


***SUNDAY TROUGH OVER THE UPPER MIDWEST REACHING NEW ENGLAND
TUESDAY MORNING***

PREFERENCE: 12Z GFS/00Z ECMWF COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

A PROGRESSIVE MID LEVEL TROUGH WILL TRACK ACROSS THE UPPER GREAT
LAKES THROUGH MONDAY MORNING AND THEN REACHING QUEBEC CANADA ON
TUESDAY.  THE SOUTHERN EXTENSION OF THE TROUGH WILL CROSS NEW
ENGLAND AND THIS WILL ALLOW A SURFACE COLD FRONT TO ADVANCE ACROSS
THE GREAT LAKES AND NORTHEAST STATES.  THE 12Z NAM IS MORE
AMPLIFIED WITH THE UPPER LEVEL HEIGHTS AS THE TROUGH CROSSES THE
NORTHEAST.  THE 00Z UKMET IS SLIGHTLY WEAKER WITH THE MAIN UPPER
LEVEL LOW CROSSING FROM ONTARIO TO QUEBEC.  THE GLOBAL MODELS AND
THE RESPECTIVE ENSEMBLE MEANS ARE IN GOOD AGREEMENT ON THIS
FEATURE AND THUS A GFS AND ECWMF COMPROMISE IS RECOMMENDED.


***LOW-AMPLITUDE SHORTWAVE CROSSING THE MIDWEST THROUGH MIDWEEK***

PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

THE GUIDANCE SHOWS A LOW-AMPLITUDE SHORTWAVE EMBEDDED WITHIN THE
DEEPER LAYER WESTERLIES CROSSING THE MIDWEST ON TUESDAY AND INTO
WEDNESDAY MORNING. THE 12Z NAM CONTINUES TO APPEAR TO BE TOO
AMPLIFIED WITH THIS SYSTEM, AND THE 00Z UKMET TOO WEAK.  THE
STRONGER MODEL CLUSTERING RESIDES WITH THE 12Z GFS AND 00Z ECMWF
IN BETWEEN, AND SO A BLEND OF THESE SOLUTIONS WILL BE PREFERRED.


***TROUGH OVER THE PACIFIC NORTHWEST***

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE MODELS HAVE A TROUGH LINGERING OVER THE NORTHWEST TUESDAY AND
WEDNESDAY. ONLY MINOR DIFFERENCES WITH TIMING/DEPTH EXIST WITH
THIS SYSTEM, SO A GENERAL MODEL COMPROMISE WILL BE PREFERRED.

HAMRICK

...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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