Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8
000
FXUS10 KWNH 281654
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1253 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 NAM/GFS MODEL EVALUATION WITH ANALYSIS AND 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 OPERATIONAL MODELS (12Z GFS/NAM AND 00Z
ECMWF/UKMET/CMC)
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...THOUGH NOT
SIGNIFICANT ENOUGH TO WARRANT REMOVAL FROM PREFERRED BLEND.
PREFERENCE IS GENERAL MODEL BLEND 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 GFS/00Z ECMWF
CONFIDENCE: SLIGHTLY BELOW AVERAGE

ENSEMBLE MEMBERS FROM THE 06Z GEFS/00Z ECMWF 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 NAM IS A BIT
STRONGER WITH THE VORT CENTERS WITH EMPHASIS A BIT FURTHER WEST
WITHIN THE ENSEMBLE SPREAD.  THE 00Z UKMET WAS THE STRONGEST AND
MOST CONSOLIDATED NEAR THE GA COAST BY FRIDAY NIGHT...SO NOT BAD
IN LOCATION BUT CLEARLY MUCH STRONGER THEN OTHER GUIDANCE.  A
MIDDLE GROUND SOLUTION WITHIN MODERATE BUT DECREASING
SPREAD...FAVORS A 12Z GFS/00Z ECMWF BLEND THOUGH SLIGHTLY BELOW
AVERAGE CONFIDENCE STILL EXISTS AT THIS TIME.

...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.