Prognostic Meteorological Discussion
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000
FXUS10 KWNH 290631
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 AM EST SAT NOV 29 2014

VALID NOV 29/0000 UTC THRU DEC 02/1200 UTC

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


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


WEAK TROUGHING IN THE NRN ROCKIES/NORTHERN PLAINS MON/TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

A COUPLE SHORTWAVES WITHIN THE BROAD TROUGH SHOW SUBTLE
DIFFERENCES, WITH THE 00Z UKMET/00Z ECMWF/00Z CANADIAN SLIGHTLY
STRONGER WITH THE LEAD SHORTWAVE WHILE THE 00Z GFS AND THE 12Z
ECMWF/00Z GEFS MEAN EMPHASIZE A BROADER TROUGH LAGGING NEAR THE
WESTERN US/CANADIAN BORDER MONDAY NIGHT/TUESDAY MORNING.  RECENT
TRENDS ARE IN THE GFS` FAVOR.  SINCE THE TROUGH IS SO BROAD, IT IS
POSSIBLE THAT THE CANADIAN/UKMET/ECMWF/CANADIAN SOLUTIONS ARE
REMAIN STRONG WITH THE LEADING SHORTWAVE.  A GENERAL MODEL
COMPROMISE STAYS CLOSE TO THE ENSEMBLE MEAN SOLUTIONS AND WHAT
BEFITS THE OVERALL PATTERN.  CONFIDENCE IN THIS CHOICE IS ABOVE
AVERAGE DUE TO DECREASING MODEL SPREAD.


SHORTWAVE MOVING THROUGH THE NORTHERN STATES
FRONT MOVING THROUGH THE GREAT LAKES/NORTHEAST SUN/MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CANADIAN COMPROMISE
CONFIDENCE: ABOVE AVERAGE

MODELS ARE SIMILAR AS A BROAD TROUGH AND SHARPLY DEFINED COLD
FRONT SWEEP ACROSS MUCH OF THE U.S. THE MAIN DIFFERENCE HAS BEEN
TIMING...WITH THE CANADIAN BEING SLOW (ITS USUAL BIAS), THOUGH IT
HAS TRENDED SLIGHTLY QUICKER SINCE ITS 12Z RUN.  THE QUICKER
NAM/GFS/UKMET/ECMWF GUIDANCE HAVE THE SUPPORT OF THE 12Z ECMWF/00Z
GEFS MEANS, WHICH ARE PREFERRED WITH ABOVE AVERAGE CONFIDENCE.


SHORTWAVES MOVING THROUGH THE SOUTHERN STATES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

SINCE THE 00Z CANADIAN HAS WEAKENED THE PACIFIC SHORTWAVE MOVING
THROUGH THE SOUTHERN STATES, DIFFERENCES WITH THIS SHORTWAVE AND A
SECOND MOVING OUT OF MEXICO INTO TEXAS HAVE BECOME QUITE SMALL.
THE PREFERENCE IS FOR A GENERAL MODEL COMPROMISE TO DEAL WITH ANY
LINGERING DETAIL ISSUES WITH ABOVE AVERAGE CONFIDENCE.

...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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