Prognostic Meteorological Discussion
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000
FXUS10 KWNH 231839
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
239 PM EDT THU OCT 23 2014

VALID OCT 23/1200 UTC THRU OCT 27/0000 UTC

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

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


DEEP CYCLONE MOVING INTO THE NORTHWEST LATE SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CANADIAN GLOBAL COMPROMISE
CONFIDENCE: AVERAGE

THE GENERAL TREND OF THE 12Z MODEL...INCLUDING THE ECMWF...IS FOR
A MORE PROGRESSIVE SYSTEM AS IT MOVES FROM THE EASTERN PACIFIC
ONSHORE EARLY SAT.  IN CONTRAST...THE 12Z CANADIAN HAS TRENDED A
LITTLE SLOWER AND MORE AMPLIFIED...MAKING IT A RELATIVE OUTLIER AS
THE UPPER SHORTWAVE/SURFACE MOVE INTO WESTERN WA ON SAT.


DEEP CYCLONE MOVING INTO NEW ENGLAND SAT/SUN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

BY EARLY SAT AS THE SYSTEM MOVES ACROSS ONTARIO AND THE UPPER
GREAT LAKES...THE 12Z NAM IS SIGNIFICANTLY FASTER THAN ITS 00Z
RUN...FALLING MUCH MORE IN LINE THAN THE MODEL CONSENSUS.  WHILE
SOME DETAIL DIFFERENCES REMAIN...THE 12Z MODELS ARE FAIRLY WELL
CLUSTERED.


UPPER TROUGH SWINGING THROUGH THE SOUTHEAST FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM COMPROMISE
CONFIDENCE: AVERAGE

THE 12Z NAM SLOWS AND AMPLIFIES THE SYSTEM MORE THAN ITS 00Z RUN
AS IT MOVES OFFSHORE LATE SAT.  THE GFS IS SHOWING A SIMILAR
TREND...BUT NOT TO THE DEGREE OF THE NAM -- WHICH BECOMES A
SLOW/AMPLIFIED OUTLIER NEAR THE END OF THE PERIOD.


CYCLONE MOVING OFFSHORE NEW ENGLAND INTO ATLANTIC CANADA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 12Z MODELS REMAIN IN GOOD AGREEMENT WITH THIS SYSTEM.


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

PEREIRA

$$





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