Prognostic Meteorological Discussion
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FXUS10 KWNH 290709
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
308 AM EDT FRI APR 29 2016

VALID APR 29/0000 UTC THRU MAY 02/1200 UTC

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

00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET/CMC/ECMWF

...SHORTWAVE/SURFACE LOW PRESSURE OVER THE MIDWEST MOVING TO THE
MID-ATLANTIC BY FRI...

PREFERENCE: 29/00Z ECMWF
CONFIDENCE: AVERAGE

THE WEAKENING UPPER LOW OVER THE MIDWEST THIS MORNING WILL SHEAR
EASTWARD ACROSS THE LOWER GREAT LAKES REGION AND NORTHERN
MID-ATLANTIC REGION THROUGH FRI. THIS WILL ALLOW SURFACE LOW
PRESSURE TO MOVE THROUGH THE OH VALLEY...WITH REDEVELOPMENT OVER
THE MID-ATLANTIC COASTAL PLAIN AND THEN THE OFFSHORE WATERS. THE
MEANS TEND TO SUPPORT TOWARD THE NON-NCEP GUIDANCE OVERALL...AT
LEAST WITH THE SHORTWAVE DETAILS. WILL CONTINUE TO FAVOR THE ECMWF
AT THE SURFACE AND ALOFT GIVEN ITS RUN TO RUN CONSISTENCY.


...UPPER LOW EJECTING OUT OF THE SOUTHWEST...
...LOW PRESSURE EVOLVING OVER THE PLAINS/MIDWEST FRI/SAT...

PREFERENCE: BLEND OF THE 29/00Z UKMET/ECMWF
CONFIDENCE: SLIGHTLY BELOW AVERAGE

WE WILL LEAN TOWARD THE RELATIVELY WELL CLUSTERED 29/00Z
UKMET/ECMWF AT THIS TIME FOR THE DEPTH OF THE TROUGH AND THE
SURFACE LOW EVOLUTION...BUT WITH SOMEWHAT LIMITED CONFIDENCE GIVEN
THE OVERALL MASS FIELD SPREAD.


...UPPER-LEVEL TROUGH/PACIFIC COLD FRONT REACHING THE NORTHWEST
THURSDAY NIGHT...
...CLOSED UPPER-LEVEL LOW OVER THE SOUTHWEST ON SATURDAY...

PREFERENCE: BLEND OF THE 29/00Z NCEP GUIDANCE AND ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 29/00Z CMC SOLUTION REMAINED A BIT SLOWER THAN THE MODEL
CONSENSUS WITH THIS SYSTEM. LATER IN THE PERIOD WHILE THE 29/00Z
UKMET REMAINED MORE PROGRESSIVE.  THINK THE 29/00Z NAM/GFS/ECMWF
FORM A STRONG CONSENSUS IN THE MIDDLE OF THE ENVELOPE OF SOLNS AND
WE WILL CONTINUE TO PREFER THEIR CONSENSUS SOLN.


...UPPER TROUGH CROSSING THE GREAT LAKES BY SAT...

PREFERENCE: GENERAL MODEL COMPROMISE BECOMING GEFS/EC ENS
COMPROMISE ON SUNDAY
CONFIDENCE: AVERAGE

THE MODELS TAKE A NORTHERN STREAM TROUGH SOUTHEAST FROM ONTARIO
AND INTO THE GREAT LAKES REGION BY SAT. BY SUNDAY...THE UKMET
BECOMES STRONGER WITH THE MID LEVEL SYSTEM NORTH OF LAKE HURON AND
SHARPER MID LEVEL TROF LAGGING OVER THE DAKOTAS.  THE GFS TENDED
TO BE SHARPER AND FASTER THAN THE REMAINING GUIDANCE.  GIVEN THAT
THE ENSEMBLE MEANS STILL CLUSTER ROUGHLY IN THE MIDDLE OF THE
ENVELOPE OF SOLNS...WILL FAVOR GEFS/ECMWF ENS MEANS ON SUNDAY.

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

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

BANN

$$





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