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000
FXUS10 KWNH 190648
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 AM EDT WED JUN 19 2013

VALID JUN 19/0000 UTC THRU JUN 22/1200 UTC

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

FINAL 00Z MODEL EVALUATION...INCLUDING THE ECMWF AND FINAL
PREFERENCES


...DEEP CLOSED LOW MOVING ACROSS THE PACIFIC NORTHWEST AND
NORTHERN ROCKIES...

PREFERENCE: BLEND OF THE 12Z ECMWF/ECMWF ENSEMBLE MEAN/00Z GFS/00Z
CANADIAN GLOBAL
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 00Z NAM/21Z SREF MEAN CONTINUED TO BE FASTER IN BODILY MOVING
THE CLOSED 500 MB LOW INTO SOUTHWEST CANADA WHILE THE 12Z-00Z
ECMWF/18-00Z GFS/12Z ECMWF ENSEMBLE MEAN/00Z CANADIAN GLOBAL SHOW
THE 500 MB LOW PERSISTING IN ID/WESTERN MT...WHILE ALLOWING A
PIECE OF THE LOW AND 700 MB WAVE TO EJECT NORTHEAST.  THE 00Z
UKMET WAS AN OUTLIER IN MAINTAINING A SECOND CLOSED LOW NEAR THE
WA/ID BORDER WITH BRITISH COLUMBIA ON THE NORTHWEST EDGE OF THE
GUIDANCE SUITE..SO THE 00Z UKMET HAS THE LOWEST PROBABILITY OF
VERIFYING AMONG THE VARIOUS SOLUTIONS.
THE 12Z ECMWF ECMWF ENSEMBLE MEAN 500 MB LOW IS CLOSE TO THE 00Z
GFS SOLUTION FRI NIGHT.
THE CLUSTERING OF THE 12Z-00Z ECMWF/00Z GFS WITH THE 12-00Z
CANADIAN GLOBAL/12Z ECMWF ENSEMBLE MEAN SUGGESTS A CONSENSUS OF
THESE SOLUTIONS BE USED.  THE LOW AMPLITUDE WAVES EJECTING NORTH
ACROSS THE NORTHERN PLAINS HAVE DIFFERENT TIMING IN DIFFERENT RUNS
SO NO ONE SOLUTION/RUN IS PREFERRED.

...500 MB WAVE MOVING FROM THE CENTRAL PLAINS-UPPER MS VALLEY ON
DAY TWO AND OHIO VALLEY DAY THREE...

PREFERENCE:  NON-UKMET MODEL COMPROMISE
CONFIDENCE:  AVERAGE

THE MODELS STILL SHOW A LOW AMPLITUDE 500 MB WAVE MOVING EAST IN
CONFLUENT FLOW FROM THE CENTRAL PLAINS TO MS VALLEY ON DAY ONE AND
WEAKENING AS IT CROSSES THE OHIO VALLEY ON DAY 2.  THE 12Z-00Z
UKMET ARE LOWEST IN AMPLITUDE WITH THIS WAVE WITH BETTER
CLUSTERING AMONG THE GFS/00Z GEFS MEAN/00Z ECMWF/12Z ECMWF
ENSEMBLE MEAN/NAM.  EVENTUALLY THIS WAVE ROUNDS THE TOP OF THE
BUILDING CENTRAL US RIDGE ON DAY 2 AND MOVES INTO THE OHIO VALLEY.
 RISING HEIGHTS AND WAVE DEAMPLIFICATION IN THE SUITE OF SOLUTIONS
SHOWS AGREEMENT ON DISSIPATION AS THE HEIGHTS INCREASE AND MID
LEVEL RIDGE INCREASES IN INTENSITY FRI NIGHT ACROSS THE REGION.
THE OVERALL TREND AGREEMENT AMONG THE MODELS/ENSEMBLE MEANS
SUGGESTS A CONSENSUS BE USED.


...BROAD UPPER LEVEL TROUGHING OVER THE GREAT LAKES AND
NORTHEAST...
...TRAILING SHORTWAVE ENERGY OVER THE SOUTHEAST COASTAL AREAS
FRI-FRI NIGHT...

PREFERENCE: 00Z GFS/00Z ECMWF/21Z SREF MEAN COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE MOST RECENT GUIDANCE SHOWS DECENT AGREEMENT WITH BROAD UPPER
LEVEL TROUGHING
ACROSS THE NORTHEAST AND LAKES DAYS 1-2 BEFORE RISING HEIGHTS AS
THE BUILDING CENTRAL US RIDGE DRIFTS EAST.  THE ECMWF/UKMET
MAINTAIN A TROUGH LONGER WHILE THE NAM/GFS/21Z SREF MEAN DEAMPLIFY
THE TROUGH SOONER.  THE 00Z ECMWF HAS TRENDED IN THE DIRECTION OF
RAISING THE HEIGHTS 1-2 DM OVER ITS FORMER 12Z RUN AT THE END OF
DAY 2 THROUGH DAY 3.

OVER THE MID ATLANTIC AND SOUTHEAST...THE MODEL MAJORITY SHOWS AN
ELONGATED 850-500 MB CYCLONIC SHEAR ZONE WITH EMBEDDED WEAK
CIRCULATIONS SFC/ALOFT FRI-FRI NIGHT.
A STALLED SFC FRONT SITS JUST OFF THE COAST OF THE CAROLINAS/GA
WITH WEAK WAVES EMBEDDED WITHIN THE BOUNDARY. MINOR
TIMING/INTENSITY DIFFERENCES SUGGESTS A MULTI-MODEL/SREF ENSEMBLE
MEAN CONSENSUS BE USED TO RESOLVE DIFFERENCES.


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

PETERSEN

$$