Prognostic Meteorological Discussion
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000
FXUS10 KWNH 221851
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 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 MODEL EVALUATION ALONG WITH FINAL PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...PLEASE NOTE THAT THE SIGNIFICANT LOSS OF THE SATELLITE INGEST
INTO THE NUMERICAL MODELS CONTINUES...WITH UNCERTAIN IMPACTS.
PLEASE REFERENCE SDM ADMIN MESSAGE FROM 1700Z UNDER AWIPS PIL
ADMNFD FOR ADDITIONAL DETAILS.

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 12Z ECMWF ADJUSTED SLIGHTLY QUICKER TO DEPART THE CLOSED LOW
FROM THE OFFSHORE WATERS OF NEW ENGLAND...SIMILAR TO THE GFS...BUT
A BIT AWAY FROM THE MEANS/PREFERENCE. THE GFS AND ECMWF HAD MADE
ONLY MINOR CHANGES FROM THEIR PREVIOUS 12/00Z RUNS BUT THE
ADJUSTMENT IN THE 12Z ECMWF IS THOUGHT TO BE A STEP AWAY FROM
PREFERRED. THE 00Z/22 ECMWF AND 12Z GFS 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 12Z OR 00Z ECMWF. THE NAM/UKMET/CMC HAVE
POORER RUN TO RUN CONTINUITY AND CONTINUE TO FALL ON EITHER SIDE
OF THE GFS/ECMWF COMBO OR ARE STRONGER/WEAKER WITH THE LOW
INTENSITY.


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

THE 12Z 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 00Z 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. THE ECMWF/CMC HAVE FLIP FLOPPED WITH
THEIR 12Z CYCLE TOWARD THE FLATTER 12Z NAM/GFS...BUT THE ENSEMBLE
MEANS CONTINUE TO SUPPORT A SOLUTION CLOSER TO THE PRIOR 00Z
ECMWF/CMC CYCLE. 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 FROM THE 22ND.


INITIAL STRONG WSW FLOW ALOFT INTO THE NORTHWEST U.S.
SHORTWAVE RACING ACROSS THE NRN GREAT LAKES BY SAT MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL COMPROMISE
CONFIDENCE: AVERAGE

THE GREATEST MODEL DIFFERENCES APPEAR BY THE WEEKEND REGARDING AN
UPPER TROUGH FORECAST TO PASS OVER THE NRN GREAT LAKES
REGION...BUT IN FACT...THE 12Z UKMET HAS ADJUSTED SOUTH TO BE
CLOSER TO THE MODEL CONSENSUS. THE 12Z ECMWF ADJUSTED A BIT FASTER
WITH THE UPPER TROUGH PASSING THROUGH SRN ONTARIO/QUEBEC BUT NO
SINGLE MODEL STANDS OUT AS UNLIKELY TO VERIFY.


LARGE UPPER TROUGH APPROACHING THE WEST COAST FOR SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z NAM 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 NON 12Z NAM BLEND...CONCERNING
BOTH THE UPPER TROUGH AND SURFACE CYCLONE. THE NAM IS NOTABLY
SLOWER THAN THE REMAINING DETERMINISTIC CONSENSUS WHICH HAS GOOD
AGREEMENT WITH THE ENSEMBLE MEANS...HOWEVER ECMWF ENSEMBLE MEMBERS
ARE NOTABLY SLOWER AT 00Z/26 COMPARED TO MANY OF THE GEFS AND
DETERMINISTIC RUNS CONCERNING THE UPPER TROUGH AXIS WHICH REDUCES
CONFIDENCE.


FRONTAL ZONE STALLED INVOF THE FL KEYS THROUGH SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: A 12Z GFS/ECMWF/UKMET 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 12Z 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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