Prognostic Meteorological Discussion
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000
FXUS10 KWNH 240426
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1225 AM EDT MON APR 24 2017

VALID APR 24/0000 UTC THRU APR 27/1200 UTC

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

00Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE ITS SHORT
RANGE FORECAST.


SYSTEM MOVING INTO THE WEST WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THE SYSTEM MOVING INTO THE
WEST WEDNESDAY.  A COMPROMISE OF THE AVAILABLE GUIDANCE -- SIMILAR
TO THE PARALLEL VERSION OF THE NATIONAL BLEND OF MODELS -- LOOKS
GOOD HERE TO DEAL WITH ANY LINGERING DETAIL ISSUES WITH ABOVE
AVERAGE CONFIDENCE.


QUASI-PHASED SYSTEM MOVING ACROSS THE WEST INTO THE PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: CANADIAN/ECMWF COMPROMISE
CONFIDENCE: NO BETTER THAN AVERAGE

THE GUIDANCE HAS SHOWN MARKED CHANGES SINCE THIS TIME YESTERDAY,
GENERALLY SHOWING A SLIGHTLY SLOWER AND MORE CLOSED SOLUTION.
WHILE THIS IS IN THE DIRECTION OF OLDER UKMET SOLUTIONS, THE 12Z
UKMET REMAINS MORE CLOSED AND MORE SOUTHERLY THAN THE OTHER
GUIDANCE HERE.  THE 00Z GFS USES CONVECTIVE/GRIDSCALE FEEDBACK
BULL`S EYES TO DRAG ITS NORTHERN STREAM TROUGH TOO QUICKLY INTO
THE GREAT LAKES -- IT WAS NOT CONSIDERED USEFUL.  THE 18Z GEFS
MEAN AND 12Z ECMWF ENSEMBLE MEAN FAVOR A MORE 00Z NAM/12Z
CANADIAN/12Z ECMWF SOLUTION ALOFT.  AT THE SURFACE, DUE TO THE
NAM`S DEPTH ALOFT, ITS SURFACE SOLUTION LIES ON THE NORTHERN
FRINGE OF THE 12Z GLOBAL ENSEMBLE SPREAD.  PREFER A COMPROMISE
BETWEEN THE 12Z CANADIAN/12Z ECMWF FOR NOW, PENDING THE RECEIPT OF
MORE 00Z GUIDANCE, WITH CONFIDENCE NO BETTER THAN AVERAGE.


DEEP SYSTEM MOVING UP THE EAST COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z NAM IS LAGGING IN THE RECURVATURE OF THIS SYSTEM, PERHAPS
DUE TO ITS STRONGER RIDGE IN SOUTHEAST CANADA.  SINCE THE OTHER
GUIDANCE LIES BETWEEN THE 18Z GEFS MEAN AND 12Z ECMWF ENSEMBLE
MEAN, FAVOR A NON-NAM COMPROMISE (00Z GFS, 12Z CANADIAN, 12Z
UKMET, AND 12Z ECMWF) WITH ABOVE AVERAGE CONFIDENCE.


WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML... /ALL LOWER CASE/
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML... /ALL LOWER CASE/

ROTH

$$





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