Prognostic Meteorological Discussion
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FXUS10 KWNH 031626
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1226 PM EDT TUE MAY 03 2016

VALID MAY 03/1200 UTC THRU MAY 07/0000 UTC

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

12Z EVALUATION OF THE NAM/GFS ALONG WITH INITIAL
PREFERENCES/CONFIDENCE

SURFACE LOW DEVELOPING ON A COLD FRONT OFF THE MID ATLANTIC COAST
WED/THU
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z ECMWF/00Z ECMWF ENSEMBLE MEAN/00Z GEFS MEAN
CONFIDENCE: BELOW AVERAGE

THE 12Z NAM WAS WITH THE CONSENSUS ON THE TIMING OF THE COLD FRONT
ACROSS THE MID ATLANTIC COAST...YET IS FURTHER WEST WITH THE
SURFACE LOW (EVEN FURTHER WEST THAN THE 09Z SREF MEAN). THE 12Z
GFS CONTINUES ITS TREND OF PLACING THE SURFACE LOW FURTHER
WEST...DESPITE THE MID LEVEL HEIGHTS BEING ROUGHLY THE SAME AS THE
MODEL CONSENSUS.

MOST OF THE MEMBERS OF THE 00Z ECMWF ENSEMBLE/00Z GEFS WERE
FURTHER EAST THAN THE 12Z NAM OR GFS...SO THE PREFERRED SURFACE
LOW POSITION WAS CLOSER TO A BLEND OF THE 00Z ECMWF/00Z ECMWF
ENSEMBLE MEAN/00Z GEFS MEAN. HOWEVER...GIVEN THE SPREAD...FORECAST
CONFIDENCE IN THE PLACEMENT OF THE LOW IS BELOW AVERAGE.


CLOSED MID LEVEL LOW TRACKING FROM THE UPPER GREAT LAKES WED TO
THE MID ATLANTIC
STATES THU INTO FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/00Z ECMWF BLEND
CONFIDENCE: AVERAGE

THE 12Z NAM WAS FURTHER SOUTH WITH THE MID LEVEL CLOSED LOW BY THU
ACROSS THE MID ATLANTIC STATES...CLOSE TO THE 00Z CMC POSITION.
THE 12Z GFS WAS CLOSE TO THE MIDDLE OF THE CONSENSUS WITH THE MID
LEVEL LOW...TRENDING SLOWER AND FURTHER WEST THAN THE 00Z GFS
SOLUTION. THE 12Z GFS POSITION IS CLOSE TO THE 00Z ECMWF/00Z ECMWF
ENSEMBLE MEAN/00Z GEFS MEAN POSITIONS...SO A BLEND OF THE LATEST
OPERATIONAL GFS/ECMWF WAS PREFERRED.


CLOSED LOW REACHING THE CA COAST THU INTO FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET SOLUTION
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 00Z UKMET SLOWS WITH TIME AS THE MID LEVEL CLOSED SYSTEM
APPROACHES THE CA COAST...ESPECIALLY DURING FRI. OTHERWISE...THE
12Z NAM/GFS WERE CLOSE TO THE MIDDLE OF THE CONSENSUS WITH THE
PLACEMENT OF THE CLOSED MID LEVEL SYSTEM...SO A BLEND EXCLUDING
THE SLOWER 00Z UKMET IS PREFERRED.


...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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