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000
FXUS10 KWNH 231837
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
236 PM EDT THU MAY 23 2013

VALID MAY 23/1200 UTC THRU MAY 27/0000 UTC

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


12Z MODEL EVALUATION...INCLUDING FINAL PREFERENCES

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


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

PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THE LATEST GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE DETAILS OF
THIS DEEP UPPER LOW THROUGH FRI...AND THEN THERE IS A GRADUAL
INCREASE IN SPREAD THEREAFTER AS THE MODELS SHOW SOME DISAGREEMENT
WITH HOW UPSTREAM SHORTWAVE ENERGY DIGS IN FROM THE GULF OF AK.
THE TREND HAS BEEN FOR A STRONGER LOBE OF THE CLOSED LOW TO BE
OVER BRITISH COLUMBIA AND ALBERTA ON SAT...WHILE WEAKENING THE
PIECE OVER THE E-PAC. OVERALL...RECENT MODEL GUIDANCE IS
CLUSTERING BETTER NOW AND AGREES THAT THE CLOSED LOW EVOLVING OVER
THE PAC NW EARLY IN THE PERIOD SHOULD REORGANIZE OVER SWRN CANADA
IN AN ELONGATED FASHION ON SAT WITH LIKELY TWO DISTINCT CENTERS AS
SHORTWAVE ENERGY PIVOTS AROUND A MEAN CENTER. THE 12Z CMC HAS
TEMPERED ITS STRONGER SECONDARY SHORTWAVE APPROACHING THE WEST
COAST AND CAN NOW BE INCLUDED IN THE OVERALL PREFERENCE.


...DEEP UPPER TROUGH/CLOSED LOW MOVING FROM THE MIDWEST TO THE
NORTHEAST...

PREFERENCE: NON 12Z UKMET CONSENSUS
CONFIDENCE: AVERAGE

THERE HAS BEEN A STRENGTHENING TREND IN THE GUIDANCE REGARDING THE
CLOSED LOW NEAR LONG ISLAND LATE SATURDAY...AS MORE RECENT MODEL
GUIDANCE SEEMS TO HAVE A BETTER HANDLE ON PHASING OF A MID LEVEL
SHORTWAVE APPROACHING FROM THE LOWER GREAT LAKES. CONSIDERING 12Z
& 00Z RUNS...THE GFS HAS HELD THE BEST CONTINUITY OVER THE PAST 36
HRS AND THE 12Z NAM/ECMWF MATCH THIS SOLUTION THE BEST OF THE
DETERMINISTIC RUNS. THE 12Z CMC IS NEXT IN LINE...BUT THE 12Z
UKMET HAS BEEN FLIP FLOPPING BETWEEN A SLOWER/QUICKER DEPARTURE OF
THE CLOSED LOW. THE OFFICIAL PREFERENCE HAS SUPPORT FROM A
MAJORITY OF ENSEMBLE MEMBERS AND THE 00Z EC MEAN WHICH DO NOT
FAVOR THE QUICKER UKMET.


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

OTTO

$$