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000
FXUS10 KWNH 250651
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 AM EDT SAT MAY 25 2013

VALID MAY 25/0000 UTC THRU MAY 28/1200 UTC

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


FINAL 00Z MODEL EVALUATION...INCLUDING THE UKMET/GEM GLOBAL AND
THE ECMWF


NO SIGNIFICANT INITIALIZATION ERRORS ARE SEEING IMPACTING THE
SHORT RANGE FORECAST.

...INITIAL DEEP UPPER TROUGH/CLOSED LOW OVER THE NORTHWEST...

PREFERENCE: BLEND OF THE 00Z GFS/00Z ECMWF
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE LATEST GUIDANCE OVERALL IS IN VERY GOOD AGREEMENT WITH THE
DETAILS OF THE DEEP UPPER LOW AT LEAST UNTIL EARLY SUN...WITH AN
INCREASE IN SPREAD THEREAFTER WITH THE HANDLING OF ADDITIONAL
SHORTWAVE ENERGY DIGGING INLAND ACROSS THE PAC NW FROM THE E PAC.
ALL OF THE MODELS PIVOT ONE CLOSED LOW CENTER UP OVER SRN/CNTRL
ALBERTA THROUGH SAT...WITH ANOTHER CENTER FOCUSED OFF THE WA
COAST. THE LATTER FEATURE SHOULD THEN EJECT INLAND OVER THE PAC NW
ON SUN AND WEAKEN...BUT THE 00Z ECMWF...00Z GEM GLOBAL AND 00Z
UKMET HANG ON TO A BIT MORE ENERGY THAN THE 00Z NAM/00Z GFS CAMP
AND SUPPORT THE REFORMATION OF A CLOSED LOW OVER SRN SASKATCHEWAN
BY THE END OF THE PERIOD. THE 12Z ECENS MEAN AND ESP THE 00Z GEFS
MEAN SUGGEST SOMEWHAT WEAKER SOLNS. ACCOUNTING FOR THE MODEL
SPREAD...WILL CONTINUE TO LEAN TWD A GFS/ECMWF BLEND ATTM.


...SHORTWAVE TROUGH DIGGING INTO THE PACIFIC NORTHWEST/GREAT BASIN
BY EARLY TUES...

PREFERENCE: NON-ECMWF CONSENSUS
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE 00Z GFS...00Z NAM AND 12Z UKMET ARE AMONG THE WEAKER SOLNS
WITH THE ARRIVAL BY EARLY TUES OF ADDITIONAL SHORTWAVE ENERGY IN
ACROSS THE PAC NORTHWEST AND GRT BASIN...WITH THE 12Z GEM GLOBAL
AND ESP THE 12Z ECMWF NOTABLY STRONGER. THE 00Z UKMET HOWEVER HAS
TRENDED A BIT SHARPER...ESP OVER THE PAC NW WITH A CLOSED LOW
FEATURE THAT IT NOW HAS. THE 00Z ECMWF AND 00Z GEM GLOBAL HAVE
TRENDED A BIT FLATTER WHICH IS A TREND TWD THE 00Z GFS. OVERALL
THOUGH...THE 00Z ECMWF IS THE STRONGEST OF ALL THE 00Z MODEL
GUIDANCE WITH THIS NEXT SHORTWAVE TROUGH. WILL MAINTAIN THE PREV
MODEL PREFERENCE ATTM OF A NON-ECMWF CONSENSUS...AS IT DOES LOOK
LIKE THE ECMWF IS STILL ATTEMPTING TO DIG JUST A TAD TOO MUCH
ENERGY INTO THE GRT BASIN BY THE END OF THE PERIOD...AND THIS IS
SUPPORTED BY THE 00Z GEFS MEAN.


...MID LEVEL SHORTWAVE TROUGH EJECTING OUT ACROSS THE CENTRAL
PLAINS/MIDWEST SUN NIGHT/MON...

PREFERENCE: NON-NAM CONSENSUS
CONFIDENCE: AVERAGE

THE 00Z NAM IS A STRONG OUTLIER WITH THIS SYS. THE 00Z UKMET
TRENDED A LITTLE SLOWER AND STRONGER WITH ITS VORT ENERGY AND IS
NOW MUCH BETTER CLUSTERED WITH THE 00Z GFS...00Z GEM GLOBAL AND
THE 00Z ECMWF. A NON-NAM CONSENSUS WILL NOW BE PREFERRED.


...MID LEVEL SHORTWAVE TROUGH LIFTING THROUGH THE UPPER MIDWEST
MON NIGHT/TUES...

PREFERENCE: NON-GEM GLOBAL CONSENSUS
CONFIDENCE: AVERAGE

THE 00Z GEM GLOBAL APPEARS TOO INTENSE WITH THE NEXT IN A SERIES
OF VORT IMPULSES LIFTING OUT OF THE PLAINS AND INTO THE UPPER
MIDWEST MON NIGHT AND TUES. THE REMAINING 00Z GLOBAL MODEL
GUIDANCE WAS REASONABLY WELL CLUSTERED TOGETHER. A NON-GEM GLOBAL
CONSENSUS WILL BE PREFERRED.


...DEEP UPPER TROUGH/CLOSED LOW LIFTING THROUGH THE
MID-ATLANTIC/NORTHEAST...

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE LATEST MODELS ARE NOW IN VERY GOOD AGREEMENT WITH THE
EVOLUTION OF THE DEEP LYR CLOSED LOW LIFTING NEWD OUT OF THE
MID-ATLANTIC AND UP THROUGH NEW ENGLAND OVER THE NEXT COUPLE OF
DAYS. WILL PREFER A GENERAL MODEL COMPROMISE ATTM.


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

ORRISON

$$