999
FXUS10 KWNH 100647
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
146 AM EST SUN NOV 10 2019
VALID NOV 10/0000 UTC THRU NOV 13/1200 UTC
..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
..00Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...AMPLIFYING MID-LEVEL TROUGH AXIS INTO THE NORTH-CENTRAL U.S.
FOR MONDAY...
..SURFACE LOW IN THE VICINITY OF NEW ENGLAND TUESDAY MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET BLEND
CONFIDENCE: AVERAGE
..07Z UPDATE
THE 00Z SUITE OF DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT NOW
REGARDING THE SHORTWAVE TROUGH AND SURFACE LOW TRACK. WHILE THE
00Z UKMET ADJUSTED FAVORABLY WITH RESPECT TO ITS PREVIOUS 12Z
CYCLE, THE UKMET REMAINS A BIT MORE PROGRESSIVE AND OFFSHORE WITH
THE SURFACE LOW NEAR NEW ENGLAND THAN IDEAL. A NON 00Z UKMET BLEND
IS PREFERRED TO SMOOTH OUT REMAINING SMALLER SCALE DIFFERENCES.
..PREVIOUS DISCUSSION FOLLOWS
THERE IS GOOD AGREEMENT WITH THE UPPER TROUGH AMPLITUDE AND TIMING
AS IT NEARS THE GREAT LAKES REGION WITH MINOR DIFFERENCES SHOWING
UP AFTER TUESDAY MORNING. THE 12Z UKMET IS FLATTER AND FASTER WITH
THE SHORTWAVE, RESULTING IN AN EASTWARD DISPLACED SURFACE LOW
EARLY TUESDAY. MEANWHILE, THE 12Z CMC BECOMES SLIGHTLY
SLOWER/DEEPER WITH THE UPPER TROUGH PLACEMENT RESULTING IN A
SURFACE LOW DISPLACED TO THE SOUTH A BIT OF THE AGREEABLE 00Z NAM,
00Z GFS AND 12Z ECMWF.
THE GOOD AGREEMENT WITH THE SURFACE LOW AMONG THE 00Z NAM/00Z
GFS/12Z ECMWF IS BROKEN UP BY THE 18Z AND 12Z GEFS/12Z ECMWF MEAN
SURFACE LOWS DISPLACED SLIGHTLY SOUTH AND EAST OF THE
DETERMINISTIC CONSENSUS. THEREFORE, BLENDING THE NAM/GFS/ECMWF
WITH THE 12Z ECMWF MEAN IS PREFERRED TO ACCOUNT FOR THE
DISPLACEMENT OF THE MEANS RELATIVE TO THE DETERMINISTIC AGREEMENT.
..COLD FRONT NEARING THE PACIFIC NORTHWEST ON TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
..07Z UPDATE
ENSEMBLE SPAGHETTI PLOTS AT 500 MB, SHOWING THE 546 DAM LINE
INDICATE THE SOMEWHAT STRONGER 00Z ECMWF/CMC AND 00Z NAM MODELS
ARE ON THE STRONGER EDGE OF THE MAJORITY OF MEMBERS. HOWEVER, THE
RUN TO RUN CONSISTENCY OF THE ECMWF AND CMC CAN'T BE IGNORED. FOR
NOW, A BLEND OF THE SOMEWHAT FLATTER 00Z GFS WITH THE MORE ROBUST
00Z ECMWF/CMC IS PREFERRED WITH THE 00Z UKMET FASTER AND FLATTER
AT 500 MB.
..PREVIOUS DISCUSSION FOLLOWS
COLD FRONTAL TIMING INTO THE PACIFIC NORTHWEST IS GOOD WITH THE
LATEST GUIDANCE. DIFFERENCES SHOW UP WITH THE CORRESPONDING
SHORTWAVE DOWNSTREAM INTO THE NORTH-CENTRAL U.S. THE 12Z CMC
STANDS OUT WITH A STRONGER/FASTER SHORTWAVE WHILE THE 12Z UKMET IS
WEAKER BY 12Z/13. A BLEND OF THE 00Z NAM, 12Z ECMWF AND 00Z GFS IS
REASONABLE GIVEN BETTER AGREEMENT TO THE ENSEMBLE MEANS.
..CLOSED LOW OVER NORTHWESTERN MEXICO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 00Z UKMET BLEND
CONFIDENCE: AVERAGE
..07Z UPDATE
ONLY THE 00Z UKMET REMAINS AS A FASTER OUTLIER REGARDING THE 500
MB LOW TRACK ACROSS NORTHWESTERN MEXICO. STRONG ENSEMBLE SUPPORT
FOR A SLOWER, NON-UKMET TRACK, LEAVES THE 00Z UKMET AN UNLIKELY
PICK FOR THIS SYSTEM. THE PREFERENCE IS FOR A NON-00Z UKMET BLEND.
..PREVIOUS DISCUSSION FOLLOWS
ENSEMBLE SPREAD IS MODEST BY 12Z/13 BUT THE 12Z CMC IS SLOWER AND
12Z UKMET FASTER THAN THE MIDDLE OF THE SPREAD. THE MIDDLE OF THE
SPREAD, TIGHTER CLUSTERING AND ENSEMBLE MEANS SUPPORTS A BLEND OF
THE 00Z NAM, 00Z GFS AND 12Z ECMWF.
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500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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