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Model Diagnostics Discussion
 
(Caution: Version displayed is not the latest version. - Issued 1726Z Feb 25, 2015)
 
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Geographic Boundaries -  Map 1: Color  Black/White       Map 2: Color  Black/White


MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1226 PM EST WED FEB 25 2015

VALID FEB 25/1200 UTC THRU MAR 01/0000 UTC

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

12Z MODEL EVALUATION...INCLUDING THE NAM/GFS AND UKMET


...SHORTWAVE TROUGH TRACKING FROM THE LOWER MS VALLEY TO THE
MID-ATLANTIC...
...SURFACE LOW TRACKING FROM THE GULF OF MEXICO TO OFFSHORE THE
MID-ATLANTIC...

PREFERENCE: BLEND OF THE 12Z GFS AND 00Z ECMWF
CONFIDENCE: AVERAGE

IT IS IMPORTANT TO NOTE THAT BOTH THE 12Z NAM AND 12Z GFS
INITIALIZED THEIR 850 MB TEMPS TOO COLD...AND TO THE ORDER OF AS
MUCH AS 2 TO 4 C WITHIN THE CONFINES OF THE SHORTWAVE EJECTING
ACROSS THE LOWER MS VALLEY THIS MORNING. THIS IS BASED IN
PARTICULAR ON 12Z RAOB DATA AS REPORTED BY FWD...LZK AND SHV. THIS
SUGGESTS POTENTIALLY BOTH THE NAM AND GFS OVERDOING THE LEVEL OF
ACTUAL DYNAMIC COOLING THROUGH THE COLUMN.

THERE HAS BEEN A SUBTLE TREND IN THE 12Z NAM/12Z UKMET AND 12Z GFS
TO HANG ON TO A SLIGHTLY STRONGER SHORTWAVE EJECTING ACROSS THE
GULF COAST STATES AND THEN LIFTING NORTHEAST ACROSS THE
MID-ATLANTIC REGION THROUGH EARLY THURS. THE ENERGY WILL BE
GRADUALLY SHEAR OUT AS IT ENCOUNTERS DEEPER LAYER CONFLUENT FLOW
DOWNSTREAM...BUT THE LATEST TRENDS WOULD TEND TO FAVOR A SLIGHTLY
STRONGER LOW CENTER LIFTING NORTHEAST OUT OF THE GULF OF MEXICO
LATER TODAY AND THEN OFF THE SOUTHEAST AND MID-ATLANTIC COASTS
TONIGHT THROUGH EARLY THURS.

THE 12Z NAM AND 09Z SREF MEAN LOW TRACKS ARE STILL OVERALL A TAD
LEFT OF THE MULTI-MODEL CONSENSUS WHICH IS BEST REFLECTED BY THE
12Z GFS/00Z ECMWF. HOWEVER...THE 12Z UKMET IS GETTING VERY CLOSE
TO THE NAM/SREF CAMP. THE 12Z GFS AND 00Z ECMWF CLUSTER WELL WITH
THEIR LOW TRACKS...BUT THE GFS IS A TAD MORE PROGRESSIVE. THE 00Z
GEM IS A TAD MORE SUPPRESSED AND GRADUALLY THE FASTEST SOLUTION.
THE 06Z GEFS MEAN AND 00Z ECENS MEAN STRONGLY FAVOR THE
MULTI-MODEL CONSENSUS AS LED BY THE GFS AND ECMWF SOLUTIONS...AND
SO THIS WILL BE THE PREFERENCE FOR THE TIME BEING PENDING THE
ARRIVAL OF THE NEW GEM AND ECMWF.


...STRENGTHENING TROUGHING OVER THE GREAT LAKES/NORTHEAST THROUGH
FRI...

PREFERENCE: NON-UKMET CONSENSUS
CONFIDENCE: ABOVE AVERAGE

THE 12Z UKMET GRADUALLY BECOMES A BIT STRONGER THAN THE
MULTI-MODEL CONSENSUS AS THE ENERGY REACHES THE NORTHEAST ON FRI.
WILL PREFER A NON-UKMET CONSENSUS AS THE REMAINING MODELS ARE WELL
CLUSTERED.


...UPPER TROUGH AMPLIFYING OVER THE WEST FRI INTO SAT...
...LOW PRESSURE OVER THE GREAT BASIN...

PREFERENCE: BLEND OF THE 12Z GFS/00Z GEM AND 00Z ECMWF...OR 00Z
ECENS MEAN
CONFIDENCE: BELOW AVERAGE

THE ENSEMBLE SPREAD REMAINS LARGE WITH AN UPPER TROUGH FORECAST TO
AMPLIFY ACROSS THE WEST LATER THIS WEEK...BUT THE INDIVIDUAL
ENSEMBLE MEMBERS HAVE TRENDED AWAY FROM THE STRONGER UKMET SINCE
YESTERDAY. THE STRONGER DETERMINISTIC CLUSTERING/CONSENSUS
INVOLVES THE 00Z GEM/00Z ECMWF AND 12Z GFS. THE 12Z UKMET IS STILL
TOO DEEP IT APPEARS...AND THE 12Z NAM IS A LITTLE WEAKER. THE 00Z
ECENS MEAN STRONGLY CLUSTERS WITH THE GEM/ECMWF AND GFS
CAMP...WITH THE GEFS MEAN SUGGESTING A SOMEWHAT WEAKER EVOLUTION
AND EVEN WEAKER THAN THE NAM. WILL LEAN TOWARD THE STRONGER
CONSENSUS...BUT CONFIDENCE REMAINS LIMITED.

www.wpc.ncep.noaa.gov/html/model2.shtml...

www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

ORRISON