Prognostic Meteorological Discussion
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FXUS10 KWNH 231720
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
119 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 NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO DEGRADE THEIR
SHORT-RANGE FORECASTS.


DEEP CYCLONE MOVING INTO THE NORTHWEST LATE SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM/GFS/UKMET
CONFIDENCE: BELOW AVERAGE

THE GENERAL TREND OF THE NAM/GFS/UKMET...IS FOR A MORE PROGRESSIVE
SYSTEM AS IT MOVES FROM THE EASTERN PACIFIC ONSHORE EARLY SAT.  IN
CONTRAST...THE 12Z CANADIAN HAS TRENDED SLOWER AND ALONG WITH THE
00Z ECMWF IS SLOWER THE 12Z NAM/GFS/UKMET SAT INTO EARLY SUN.
WHILE CONFIDENCE IS LIMITED...WILL LEAN TOWARD THE MAJORITY --
WHICH IS SUPPORTED BY THE 12Z GEFS MEAN AS WELL.


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 AND 00Z ECMWF 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 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 GUIDANCE...INCLUDING THE 12Z NAM/GFS...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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