Prognostic Meteorological Discussion
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000
FXUS10 KWNH 291637
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1237 PM EDT WED OCT 29 2014

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

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


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


AMPLIFIED TROUGH APPROACHING WESTERN NORTH AMERICA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF COMPROMISE
CONFIDENCE: ABOVE AVERAGE

WITH NO MAJOR CHANGES IN THINKING BY THE NCEP MODELS...THERE WAS
LITTLE CHANGE TO THE MODEL PREFERENCE BY

THE 00Z NAM IS SLOW WITH THIS SYSTEM -- ITS USUAL BIAS -- WHILE
THE 00Z UKMET IS SLIGHTLY QUICK WITH THIS SYSTEM -- ITS USUAL
BIAS.  THE 00Z CANADIAN IS DEEPER/SHARPER ALOFT, WHICH LEADS TO A
STRONGER SURFACE LOW APPROACHING CALIFORNIA -- ONE OF ITS USUAL
BIASES.  THE 00Z GFS/00Z ECMWF LIE IN THE MIDDLE OF THE GUIDANCE
SPREAD AND ARE CLOSE TO THE 12Z ECMWF/00Z GEFS ENSEMBLE MEANS.


TROUGH AMPLIFYING ACROSS EASTERN NORTH AMERICA
CLOSED LOW POTENTIALLY DROPPING INTO THE CAROLINAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/GFS COMPROMISE
CONFIDENCE: BELOW AVERAGE

THIS TROUGH AMPLIFIES DUE TO UPSTREAM AMPLIFICATION OF A
TROUGH/RIDGE COUPLET NEAR THE WEST COAST/GREAT PLAINS
RESPECTIVELY.  THE MODELS STILL MAINTAIN BETTER CONVERGENCE THAT
APPEARED IN THE 29/00Z GUIDANCE.  THE 12Z NAM REMAINED DEEPER AND
ON THE SOUTHWEST SIDE OF THE GUIDANCE BY SATURDAY MORNING -- ITS
USUAL BIAS.  THE 00Z GEFS MEAN/00Z UKMET/00Z ECMWF FORMED A FAIRLY
STRONG ALLIANCE.  SO STILL THINK A COMPROMISE BETWEEN THE OLD
ECMWF AND THE NEW GFS HAS THE BEST SUPPORT.

...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

BANN

$$





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