Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7
000
FXUS10 KWNH 281846
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
246 PM EDT TUE JUL 28 2015

VALID JUL 28/1200 UTC THRU AUG 01/0000 UTC

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

12Z MODEL EVALUATION WITH ANALYSIS AND FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO AFFECT SHORT TERM
FORECAST ERRORS


STRONG UPPER TROUGH CROSSING THE DAKOTAS ON TUE REACHING JAMES BAY
BY FRIDAY WITH ATTENDANT COLD FRONT CROSSING THE MID-MISS VALLEY
EARLY WED TOWARD THE U.S. EAST COAST BY FRI.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 12Z OPERATIONAL MODELS
CONFIDENCE: AVERAGE

FAIRLY STRONG AGREEMENT CONTINUES TO EXIST WITH THE
TIMING/STRENGTH IN HANDLING THE UPPER LOW AND SURFACE REFLECTIONS
HAS THEY CROSS THE NORTHERN PLAINS INTO THE GREAT LAKES WED INTO
THUR AND THROUGH THE NORTHEAST/MID-ATLANTIC BY FRIDAY.  THE 12Z
NAM/GFS HAVE TRENDED A BIT FASTER ELONGATING THE UPPER TROUGH
FURTHER SOUTH AND EAST THE NAM MORE SO THAN THE GFS.  THIS HAS
BEEN FOLLOWED BY THE 12 ECMWF...EVEN OUTPACING THE NAM/GFS BY DAY
3 WHEN THE BASE BECOMES EVEN FURTHER NEGATIVE TILT ACROSS
SOUTHEAST CANADA.  A PREFERENCE TOWARD A 12Z OPERATIONAL MODEL
BLEND REMAINS BUT WITH ENOUGH SPREAD AT DAY 3 TO REMAIN AT AVERAGE
CONFIDENCE.


LOW-MID LEVEL TROUGH AXIS IMPACTING THE SOUTHEAST/FL PENINSULA
THROUGH THU
POTENTIAL UPPER TROUGH / CLOSED LOW IN THE WRN ATLANTIC BY MID TO
LATE WEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 12Z NAM/GFS/ECMWF
CONFIDENCE: AVERAGE

ENSEMBLE MEMBERS FROM THE 06Z GEFS/00Z ECMWF/09Z SREF ENSEMBLE
ALONG WITH THEIR OPERATIONAL COMPONENTS HAVE DECREASED IN SPREAD
WITH BETTER AGREEMENT IN THE EVOLUTION/DEPTH OF THE TROF AXIS
BECOMING A CLOSED LOW BY FRIDAY NORTH OF BAHAMAS.  THE 12Z ECMWF
CONTINUED ITS TREND TOWARD THE GFS SOLUTION FARTHER UP THE
CAROLINA COAST WITH THE SURFACE LOW...AS WELL AS RESOLVING WEAKER
VORT CENTER OVER THE WESTERN GULF...IN LINE WITH THE 12Z NAM/GFS.
THE 12Z NAM IS A BIT STRONGER WITH THE VORT CENTERS COMPARED TO
THE GFS/ECMWF...IN LINE WITH ITS BIAS...HOWEVER HAS GOOD
ORIENTATION AND LOCATION TO THE VORT CENTERS OVER THE WESTERN GULF
AND NORTH OF THE BAHAMAS TO BE INCLUDED INTO THE BLEND.  THE 12Z
UKMET REMAINS THE STRONGEST AND MOST CONSOLIDATED WITH VORTICITY
ENERGY AS WELL AS DEVELOPING A STRONGER SURFACE LOW NEAR THE
CAROLINA COAST BY FRIDAY NIGHT.   THE 12Z CMC REMAINS QUITE WEAK
WITH LITTLE TO NO TROF DEVELOPMENT.  AS SUCH A BLEND OF THE 12Z
NAM/GFS/ECMWF IS PREFERRED WITH CONTINUED BETTER AGREEMENT AND
REDUCING SPREAD...CONFIDENCE IS INCREASED TO AVERAGE.


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

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

GALLINA

$$





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.