Prognostic Meteorological Discussion
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FXUS10 KWNH 010449
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1245 AM EDT WED APR 01 2015

VALID APR 01/0000 UTC THRU APR 04/1200 UTC

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

00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES

INITIALIZATION ERRORS WITH THE NAM/GFS DO NOT SEEM TO DEGRADE
THEIR SHORT RANGE FORECASTS.


SHORT WAVE MOVING INTO THE PACIFIC NORTHWEST FRI

PREFERENCE: 00Z GFS/12Z ECMWF/12Z UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 00Z NAM IS CLOSE TO THE MODEL CONSENSUS AT THE START OF DAY
3...BUT SLOWS WITH TIME AS IT ENTERS SOUTHERNMOST BRITISH
COLUMBIA.  THE 00Z GFS SLOTS WELL WITH THE 12Z ECMWF AND 12Z UKMET
WITH RESPECT TO TIMING AND STRENGTH. THE 12Z CMC SLOWS WITH TIME
WITH THE SHORT WAVE AS WELL.


SHORT WAVE MOVING THROUGH THE CENTRAL PLAINS THU/OH VALLEY FRI
SURFACE LOW TRACKING FROM THE SOUTHERN PLAINS THU INTO NEW ENGLAND
LATE FRI

PREFERENCE: 00Z GFS/18Z GEFS/12Z ECMWF ENSEMBLE MEAN
CONFIDENCE: AVERAGE

THE 00Z NAM SLOWS WITH TIME WITH THE SHORT WAVE AND SURFACE
LOW...PLACING THE SURFACE LOW SOUTHWEST OF THE CONSENSUS OVER
SOUTHERN NEW ENGLAND BY 04/12Z. THE 00Z GFS IS A BIT FASTER WITH
THE SHORT WAVE AND SURFACE LOW...PLACING THE SURFACE LOW OVER
EASTERN MA BY THE END OF THE PERIOD. THIS SOLUTION HAS THE SUPPORT
OF THE 18Z GEFS AND 12Z ECMWF ENSEMBLE MEAN. THE 12Z ECMWF IS THE
NORTHWEST MOST SOLUTION WITH THE SHORT WAVE AND SURFACE LOW...AND
HAS SLOWED CONSIDERABLY WITH BOTH FROM ITS PREVIOUS TWO MODEL
SOLUTIONS.


SHORT WAVE AND SURFACE FRONT CROSSING THE UPPER MIDWEST/GREAT
LAKES WED/THU

PREFERENCE: 00Z GFS/12Z ECMWF
CONFIDENCE: AVERAGE

THE 00Z NAM IS CLOSE TO THE CONSENSUS WITH THE SHORT WAVE AND
FRONT ON DAY 2...ONLY TO SLOW DURING DAY 2 AND DAY 3 OVER CENTRAL
CANADA. THE 00Z GFS SLOWED ITS SOLUTION A BIT COMPARED TO PREVIOUS
SOLUTIONS...AND NOW FITS NICELY WITH THE 12Z ECMWF...ESPECIALLY ON
DAY 2. THE 12Z UKMET CONTINUES TO BE THE SLOWER SOLUTION WITH
THESE SYSTEMS.


SHORT WAVE MOVING THROUGH THE SOUTHERN PLAINS TUE/WED AND THE
SOUTHEAST THU

PREFERENCE: 00Z GFS/12Z ECMWF/12Z CMC BLEND
CONFIDENCE: AVERAGE

THE 00Z NAM ONCE AGAIN BECOMES SLOWER WITH TIME WITH THIS SHORT
WAVE...ESPECIALLY ACROSS THE SOUTHEAST STATES. THE 00Z GFS IS IN
LINE WITH THE 12Z ECMWF/CMC WITH RESPECT TO SHORT WAVE
SPEED...THOUGH THE 12Z ECMWF REMAINS THE DEEPEST OF THE SOLUTIONS.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...

...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...


HAYES

$$





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