Prognostic Meteorological Discussion
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000
FXUS10 KWNH 240428
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1228 AM EDT SUN MAY 24 2015

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

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

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


SURFACE LOWS MOVING THROUGH THE UPPER MIDWEST MON/TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/NAM COMPROMISE
CONFIDENCE: AVERAGE

THE 12Z ECMWF WAS A SLOW OUTLIER WITH THE FIRST LOW STREAKING
THROUGH SOUTHEAST CANADA WHILE THE 12Z CANADIAN WAS STRONGER AND
FARTHER NORTH.  CONSIDERING THE CONFLUENT FLOW PATTERN THE UPPER
SHORTWAVE IS ENTERING, FASTER SHOULD BE BETTER.  A 00Z NAM/00Z
GFS/12Z UKMET SOLUTION IS PREFERRED WITH THIS FEATURE.

THE 12Z UKMET WAS THE ODD MODEL OUT HERE WITH THE SECOND LOW,
SHOWING A STRONGER SYSTEM AT THE SURFACE AND AT 700 HPA.  WHILE
THERE IS A GREAT DEAL OF SPREAD SEEN IN THE 12Z GLOBAL ENSEMBLE
GUIDANCE, THE 12Z UKMET LIES ON THE WESTERN FRINGE OF THE OVERALL
ENVELOPE.  A NON-UKMET SOLUTION IS PREFERRED HERE.  OVERALL, A
COMPROMISE OF THE 00Z NAM/00Z GFS LOOKS REASONABLE WITH CONFIDENCE
NO BETTER THAN AVERAGE CONSIDERING THE BROAD DISTRIBUTION SEEN IN
THE DETERMINISTIC AND ENSEMBLE GUIDANCE WITH THE SECOND LOW.


ELSEWHERE
~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE SHOWS REASONABLE AGREEMENT WITH THE REMAINING SYSTEMS
NEAR THE LOWER 48.


...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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