Prognostic Meteorological Discussion
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FXUS10 KWNH 221719
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
118 PM EDT WED OCT 22 2014

VALID OCT 22/1200 UTC THRU OCT 26/0000 UTC

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

12Z NAM/GFS EVALUATION ALONG WITH PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...PLEASE NOTE THAT THE SIGNIFICANT LOSS OF THE SATELLITE INGEST
INTO THE NUMERICAL MODELS CONTINUES...WITH UNCERTAIN IMPACTS...

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


CLOSED LOW SLOWLY LIFTING NEWD FROM OFF OF THE NEW ENGLAND COAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z GFS / 00Z ECMWF
CONFIDENCE: AVERAGE

THE GFS / ECMWF HAVE MADE ONLY MINOR CHANGES FROM THEIR PREVIOUS
12/00Z RUNS AND CONTINUE TO SHOW GOOD AGREEMENT TO THE LATEST
ENSEMBLE MEANS...REPRESENTING THE MIDDLE OF THE LATEST MODEL
SPREAD. THE 12Z GFS IS SLIGHTLY STRONGER WITH THE COASTAL LOW BUT
850 MB WIND MAGNITUDE DOES NOT SEEM TO VARY SIGNIFICANTLY BETWEEN
THE GFS AND ECMWF. THE NAM/UKMET/CMC HAVE POORER RUN TO RUN
CONTINUITY AND CONTINUE TO FALL ON EITHER SIDE OF THE GFS/ECMWF
COMBO.


NRN/SRN STREAM TROUGHS CURRENTLY ENTERING THE GREAT PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z ECMWF/CMC
CONFIDENCE: BELOW AVERAGE

THE NAM/GFS/GEFS HAVE LESS SHORTWAVE ENERGY WITHIN THE SRN PORTION
OF THE UPPER TROUGH FORECAST TO CROSS THE MISS VALLEY ON
THU...WHILE THE ECMWF/UKMET/CMC SHOW MORE AMPLIFICATION BY THE
WEEKEND ALONG THE EAST COAST DUE TO A GREATER INFLUENCE ON THE SRN
PORTION OF THE UPPER TROUGH. ENSEMBLE SPAGHETTI HEIGHTS SHOW A
GREAT DEAL OF SPREAD WITH ONLY SOME CONVERGENCE SINCE YESTERDAY
TOWARD THE MIDDLE OF THE SPREAD. THEREFORE...WPC WILL CONTINUE TO
FAVOR THE MIDDLE OF THE SPREAD BEST REPRESENTED BY A BLEND OF THE
00Z ECMWF/CMC.


INITIAL STRONG WSW FLOW ALOFT INTO THE NORTHWEST U.S.
SHORTWAVE RACING ACROSS THE NRN GREAT LAKES BY SAT MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET BLEND
CONFIDENCE: AVERAGE

THE GREATEST MODEL DIFFERENCES APPEAR BY THE WEEKEND REGARDING AN
UPPER TROUGH FORECAST TO PASS OVER THE NRN GREAT LAKES REGION. THE
00Z UKMET IS DISPLACED NWD OF THE MODEL CONSENSUS...AND
THEREFORE...WILL NOT BE PREFERRED.


LARGE UPPER TROUGH APPROACHING THE WEST COAST FOR SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z ECMWF/CMC BLEND
CONFIDENCE: A BIT BELOW AVERAGE

MODERATE SPREAD ENTERS THE FORECAST PICTURE BY SAT WITH VARYING
TIMING AND DEPTH ISSUES REGARDING A LARGE UPPER TROUGH AND
ASSOCIATED SURFACE CYCLONE NEARING THE WEST COAST BY SAT. THE
LATEST ENSEMBLE MEANS SUPPORT A 00Z ECMWF/CMC BLEND WITH THE 00Z
GFS SECOND CLOSEST...BUT PERHAPS A LITTLE SOUTH OF THE PREFERENCE
WITH THE SURFACE CYCLONE. THE ECMWF/CMC ARE IN THE MIDDLE OF THE
DETERMINISTIC SPREAD AND HAVE GOOD AGREEMENT WITH THE ENSEMBLE
MEANS...HOWEVER ECMWF MEMBERS ARE NOTABLY SLOWER AT 00Z/26
COMPARED TO MANY OF THE GEFS AND DETERMINISTIC RUNS CONCERNING THE
UPPER TROUGH AXIS.


FRONTAL ZONE STALLED INVOF THE FL KEYS THROUGH SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: A NON 12Z NAM/00Z CMC MODEL COMPROMISE
CONFIDENCE: BELOW AVERAGE

MODELS SHOW A STATIONARY BOUNDARY LINGERING ACROSS SOUTH FL AND
DOWN ACROSS THE FL KEYS THROUGHOUT MUCH OF THE PERIOD. THE
GUIDANCE SHOW SOME VARIABILITY IN THE PLACEMENT AND TIMING OF
WAVES TRACKING ALONG THIS BOUNDARY WITH ENSEMBLE SCATTER LOW PLOTS
SUPPORTING A VARIETY OF SOLUTIONS. THE 12Z NAM AND 00Z CMC
HOWEVER...ARE MORE AGGRESSIVE AND STAND OUT WITH LESS SUPPORT FROM
THE REMAINING BROAD MODEL CONSENSUS.



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

OTTO

$$





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