Prognostic Meteorological Discussion
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146
FXUS10 KWNH 050421
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1220 AM EDT THU MAY 05 2016

VALID MAY 05/0000 UTC THRU MAY 08/1200 UTC

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

00Z NAM/GFS EVALUATION INCLUDING PRELIMINARY MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
GFS/NAM INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


SYSTEM MOVING BY THE NORTHWEST SATURDAY NIGHT
FRONT CROSSING THE GREAT LAKES SATURDAY MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE GUIDANCE SHOWS VERY GOOD AGREEMENT WITH THESE SYSTEMS, SO WE
PREFER A GENERAL MODEL COMPROMISE TO DEAL WITH ANY LINGERING
DETAIL ISSUES WITH ABOVE AVERAGE CONFIDENCE.


SYSTEM MOVING INTO THE SOUTHWEST/GREAT BASIN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM IS SLOW/SOUTHWEST WITH THIS SYSTEM BY SUNDAY MORNING
-- ITS TYPICAL BIAS AT THIS TIME RANGE.  THE OTHER GUIDANCE SHOWS
VERY GOOD AGREEMENT, SO PREFER A COMPROMISE OF THE 12Z
CANADIAN/12Z UKMET/12Z ECMWF/00Z GFS WITH ABOVE AVERAGE CONFIDENCE.


LOW MOVING BY NEW ENGLAND THURSDAY EVENING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NAM/ECMWF COMPROMISE
CONFIDENCE: SLIGHTLY BELOW AVERAGE

THE DETERMINISTIC AND 12Z GLOBAL ENSEMBLE GUIDANCE SHOW MUCH MORE
DISPERSION THAN USUAL WITH THIS SYSTEM.  OVERALL, THE 12Z
ECMWF/00Z NAM SPLIT THE DIFFERENCE SEEN IN THE GUIDANCE, AND A
COMPROMISE OF THE TWO IS PREFERRED WITH SLIGHTLY BELOW AVERAGE
CONFIDENCE.


LOW NEAR THE MID-ATLANTIC COAST FRIDAY/SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: CLOSEST TO THE 00Z GFS
CONFIDENCE: AVERAGE

THE DETERMINISTIC/12Z GLOBAL ENSEMBLE GUIDANCE SHOWS WIDER THAN
NORMAL SPREAD WITH THIS SYSTEM AS WELL, THOUGH NOT QUITE AS WIDE
AS THE NEW ENGLAND SYSTEM.  OVERALL, THE 00Z GFS BEST FITS THE
MIDDLE OF THE ENSEMBLE LOW CLUSTERING, SO PREFER A SOLUTION
TOWARDS THE 00Z GFS WITH CONFIDENCE NO BETTER THAN AVERAGE.


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

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

ROTH
$$





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