Prognostic Meteorological Discussion
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000
FXUS10 KWNH 250426
PMDHMD

MODEL DIAGNOSTIC DISCUSSION...CORRECTION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1225 AM EDT SAT OCT 25 2014

VALID OCT 25/0000 UTC THRU OCT 28/1200 UTC

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


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


POST-TROPICAL CYCLONE ANA/
DEEP CYCLONE APPROACHING THE PACIFIC NORTHWEST MON/TUE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/UKMET/CANADIAN COMPROMISE BY DEFAULT
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 00Z NAM IS MUCH WEAKER ALOFT WITH THIS SYSTEM WHEN COMPARED TO
THE OTHER GUIDANCE.  OTHERWISE, THE 12Z ECMWF OUTPACES THE
REMAINDER OF THE GUIDANCE, INCLUDING THE 12Z ECMWF AND 18Z GEFS
MEANS, AND IS ALSO WEAKER ALOFT.  THERE SHOULD BE ENOUGH
SEPARATION BETWEEN THIS SYSTEM AND OTHER SYSTEMS ACROSS THE
NORTHEAST PACIFIC AND NORTHWEST CANADA FOR THE CYCLONE TO BE
CLOSED AT 500 HPA, SO PREFER A COMPROMISE OF THE NON-NAM,
NON-ECMWF GUIDANCE.  THIS IS IN LINE WITH THE LATEST FORECAST FROM
CPHC...SEE CPHC  PRODUCTS FOR THE LATEST INFORMATION ON HURRICANE
ANA.


DEEP CYCLONE MOVING THROUGH THE WEST AND PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: UKMET/ECMWF COMPROMISE
CONFIDENCE: SLIGHTLY ABOVE AVERAGE

THE 00Z GFS IS QUICKER THAN THE OTHER GUIDANCE LATE
MONDAY/TUESDAY, WHICH IS MOST NOTICEABLE AT THE 500 AND 700 HPA
LEVELS -- ONE OF ITS USUAL BIASES.  THE 00Z NAM/12Z CANADIAN MOVE
THE SYSTEM ALOFT A TOUCH SLOWER THAN THE OTHER GUIDANCE -- WHICH
FITS THEIR USUAL BIASES -- INCLUDING THE 12Z ECMWF AND 18Z GEFS
MEANS.  THIS PROGRESSION ISSUE ALOFT IS REFLECTED WITHIN THE NAM`S
FRONTAL PROGRESSION ACROSS THE SOUTHERN PLAINS LATE MONDAY/EARLY
TUESDAY.  OVERALL, THE FLOW PATTERN SHOULD REMAIN PROGRESSIVE WITH
DEEP CYCLONES TRACKING NEAR THE 50TH PARALLEL.


DEEP CYCLONE MOVING ACROSS NEW ENGLAND/ATLANTIC CANADA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: HIGH

THE GUIDANCE IS 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...

ROTH
$$





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