Prognostic Meteorological Discussion
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000
FXUS10 KWNH 270629
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
128 AM EST THU NOV 27 2014

VALID NOV 27/0000 UTC THRU NOV 30/1200 UTC

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
...THE 00Z HIGH-RESOLUTION ECMWF WAS NOT AVAILABLE FOR THIS
DISCUSSION...

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


TROUGH MOVING THROUGH THE NORTHERN ROCKIES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/CANADIAN COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z UKMET LAGS THE REMAINDER OF THE GUIDANCE WITH THIS SYSTEM,
WHILE THE 00Z GFS LIES ON THE FAST SIDE OF THE GUIDANCE.  THE 00Z
NAM IS STRONGER THAN THE OTHER GUIDANCE -- ITS USUAL BIAS WITH
SYSTEMS A FEW DAYS INTO THE FUTURE.  THE 00Z CANADIAN/12Z ECMWF
PAIR WELL WITH THE 12Z ECMWF/00Z GEFS MEANS, AND A COMPROMISE OF
THE TWO SHOULD TAKE CARE OF THE NAM`S DEEP BIAS WITH THE TROUGH.


SHORTWAVE APPROACHING CALIFORNIA SAT NIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: AVERAGE

THE 00Z NAM IS MUCH SLOWER IN PROGRESSING A SHORTWAVE BEING FLUNG
OUT OF THE DEEP CYCLONE WELL OFFSHORE CALIFORNIA WHEN COMPARED TO
THE OTHER GUIDANCE -- ITS USUAL BIAS WITH UPPER LEVEL SYSTEMS A
FEW DAYS INTO THE FUTURE.  THE 12Z ECMWF/00Z GEFS MEANS IMPLY ANY
SHORTWAVE IN THIS POSITION WOULD BE WEAK, WHICH ALSO BEFITS THE
LOW AMPLITUDE PATTERN IN WHICH THE SHORTWAVE IS EMBEDDED.  A
COMPROMISE OF THE 00Z GFS/00Z CANADIAN/00Z UKMET/12Z ECMWF IS
PREFERRED HERE WITH AVERAGE CONFIDENCE CONSIDERING ISSUES ACROSS
THE NORTHWEST WHICH COULD IMPACT ITS PROGRESSION INTO CALIFORNIA.


UPPER LEVEL TROUGH MOVING THROUGH NORTHERN MEXICO
TROUGH MOVING THROUGH AND LIFTING OUT OF THE EAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE GUIDANCE IS IN VERY GOOD AGREEMENT WITH THE CONSOLIDATING
NEGATIVELY TILTED TROUGH MOVING THROUGH THE NORTHEAST AND THE
SHORTWAVE MOVING THROUGH NORTHERN MEXICO.


...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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