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000
FXUS10 KWNH 191847
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 PM EDT SUN MAY 19 2013

VALID MAY 19/1200 UTC THRU MAY 23/0000 UTC

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

==============================================
FINAL 12Z MODEL EVALUATION AND PREFERENCES
==============================================
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO
SIGNIFICANTLY AFFECT THEIR LARGE SCALE OUTPUT.
==============================================

...TROUGH/DEEP CYCLONE MOVING FROM THE WEST INTO THE
PLAINS/MIDWEST...

PREFERENCE: BLEND OF 12Z GFS/ECMWF/UKMET
CONFIDENCE: AVERAGE

RELATIVELY GOOD AGREEMENT ON THE LARGE SCALE. ALL MODELS END UP IN
A SIMILAR PLACE BY THE END OF THE SHORT RANGE. THE 12Z ECMWF IS
STILL SLOWER WITH THE SHORTWAVE FORECAST TO ROTATE THROUGH
OKLAHOMA ON DAY 2. THE ECMWF IS SLIGHTLY SLOWER ON THE LARGER
SCALE AS WELL...BUT ITS SURFACE SOLUTION FORMS A REASONABLE
CLUSTER WITH THE GFS/UKMET. THE NAM IS SLIGHTLY FAST WITH THE DAY
2 OKLAHOMA SHORTWAVE...BUT ITS FORECAST MAY HAVE UTILITY FOR MANY
ASPECTS OF THIS SYSTEM THROUGH DAY 3.


...DEEP CYCLONE DROPPING TOWARDS THE PACIFIC NORTHWEST...

PREFERENCE: ANY OF THE OPERATIONAL MODELS
CONFIDENCE: ABOVE AVERAGE

AGREEMENT IS VERY GOOD HERE FOR THE TIME BEING. THE MAIN ATTRIBUTE
TO RAISE CAUTION IS THE NAM TENDENCY TO ERR ON THE DEEP/STRONG
SIDE WITH ITS 700 MB LOW AND WIND FIELDS. THIS WOULD MAINLY AFFECT
THE OREGON AND NORTHERN CA COAST ON DAY 3.


...SHORTWAVE TROUGH MOVING THROUGH CAROLINAS...
...WEAK UPPER LEVEL SYSTEM FORMING ACROSS FLORIDA...

PREFERENCE: BLEND OF 12Z NAM/GFS/ECMWF
CONFIDENCE: AVERAGE

THOUGH NOT PERFECT...A BLEND OF THE GFS AND ECMWF TENDS TO CAPTURE
THE MOST LIKELY CONFIGURATION OF THESE SOUTHERN STREAM SYSTEMS
CAUGHT IN WEAK STEERING FLOW. IN THIS CASE THE NAM JOINS THE GFS
AND SEVERAL GEFS AND ECMWF ENSEMBLE MEMBERS IN BETTER DEPICTING
THE HEIGHT FIELD WEAKNESS THAT SHOULD DEVELOP AS A SHORTWAVE DIPS
FROM TEXAS DOWN TO FLORIDA AND TAKES ON A NEGATIVE TILT.


...FRONT/LOW MOVING THROUGH/BY THE NORTHEAST MONDAY/TUESDAY...

PREFERENCE: BLEND OF 12Z NAM AND 00Z ECMWF/CANADIAN
CONFIDENCE: AVERAGE

THE GFS AND UKMET WERE FLAT WITH THE SHORTWAVE RIDGE PROGRESSING
THROUGH NEW ENGLAND BY DAY 3. THE ECMWF CONTINUES TO BE SLOW WITH
AN UPSTREAM TROUGH OVER HUDSON BAY/ONTARIO...BUT OVER NEW ENGLAND
THE ECMWF IS SIMILAR ENOUGH TO THE 12Z NAM AND 00Z CANADIAN TO
FORM AN OPERATIONAL MODEL CLUSTER CLOSE TO THE CONSENSUS SOLUTION.

...MODEL TREND GRAPHICS AT
WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML...
...500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...

BURKE
$$