Prognostic Meteorological Discussion
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583
FXUS10 KWNH 290455
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1255 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...

PRELIMINARY 00Z MODEL EVALUATION...INCLUDING THE NAM/GFS/UKMET

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

PREFERENCE: 12Z 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 WILL CONTINUE TO MAINTAIN
CONTINUITY AND CONTINUE LEANING TOWARD THE ECMWF AT THE SURFACE
AND ALOFT.


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

PREFERENCE: BLEND OF THE 29/00Z UKMET AND 28/12Z ECMWF
CONFIDENCE: SLIGHTLY BELOW AVERAGE

WE WILL LEAN TOWARD THE RELATIVELY WELL CLUSTERED 29/00Z UKMET AND
28/12Z 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 THE 28/12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 28/12Z CMC SOLUTION WAS A BIT SLOWER THAN THE MODEL CONSENSUS
WITH THIS SYSTEM. LATER IN THE PERIOD...THE 29/00Z UKMET REMAINS A
TAD WEAKER AND A LITTLE MORE PROGRESSIVE.  THINK THE 29/00Z
NAM/GFS AND THE 28/12Z 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...THOUGH...TWO
DISTINCT CAMPS FORMED WITH THE 00Z NAM/UKMET AND THE 12Z CANADIAN
LAGGING ENERGY BACK OVER THE EASTERN LAKES WHILE THE 00Z GFS AND
28/12Z ECMWF WERE MORE PROGRESSIVE.  THE GEFS/ECMWF ENS MEANS SIT
ROUGHLY IN THE MIDDLE OF THE TWO CAMPS AND PROBABLY OFFER A GOOD
COMPROMISE SOLN.

...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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