Prognostic Meteorological Discussion
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000
FXUS10 KWNH 261620
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1120 AM EST THU FEB 26 2015

VALID FEB 26/1200 UTC THRU MAR 02/0000 UTC

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

12Z NAM/GFS EVALUATION AND PRELIMINARY MODEL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT
RANGE FORECASTS.


UPPER LOW DEVELOPING NEAR L.A. LATE SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z CANADIAN/00Z UKMET LOOK SLOW WITH THIS SYSTEM`S
PROGRESSION WHEN COMPARED TO THE OTHER GUIDANCE, INCLUDING THE 00Z
ECMWF/06Z GEFS/09Z SREF MEANS.  THE 12Z NAM LOOKS MUCH TOO SHARP
WITH THIS SYSTEM OFFSHORE AS THE OVERALL APPEARANCE OF THE UPPER
TROUGH WOULD FAVOR A SOLUTION WHICH IS SOMEWHAT BROAD.  THE 00Z
ECMWF/06Z GEFS/09Z SREF MEANS SUPPORT A COMPROMISE OF THE 00Z
ECMWF/12Z GFS, WHICH IS FAVORED WITH ABOVE AVERAGE CONFIDENCE.


SHORTWAVE/FRONT NEAR THE GREAT LAKES LATE SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/UKMET COMPROMISE
CONFIDENCE: AVERAGE

THIS SYSTEM ALOFT IS EMBEDDED WITHIN A QUICK FLOW REGIME WITHIN
THE NORTHERN STREAM OF THE WESTERLIES, WHICH ELIMINATED THE
COMPLETE RULING OUT OF THE 12Z NAM/00Z CANADIAN IDEA.  WHILE THE
12Z GFS/12Z NAM/00Z ECMWF LOOK SLOWER ALOFT, BEFITTING THE 00Z
ECMWF/09Z SREF MEANS, THERE REMAIN PROGRESSION ISSUES AT THE
SURFACE IN RELATION TO THIS FEATURE.  UNTIL THE REMAINDER OF THE
12Z GUIDANCE SUITE BECOMES AVAILABLE, THE INTERMEDIATE ECMWF/UKMET
SOLUTIONS ARE PREFERRED WITH AVERAGE CONFIDENCE.


SHORTWAVE CROSSING THE MID-SOUTH/EAST SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-GFS COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 12Z GFS IS STRONGER/SLOWER WITH THIS SHORTWAVE, WHICH IS
EMBEDDED WITHIN A ZONAL/QUICK FLOW REGIME.  SINCE THIS REGIME
FAVORS SHORTWAVES THAT ARE QUICKER AND WITH LESS AMPLITUDE, FAVOR
A NON-GFS COMPROMISE WITH ABOVE AVERAGE CONFIDENCE.


TROUGH MOVING THROUGH THE NORTHEAST FRI
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE FEATURES.


...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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