300
FXUS10 KWNH 090509
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1208 AM EST SAT NOV 09 2019
VALID NOV 09/0000 UTC THRU NOV 12/1200 UTC
..SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
...00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES AND
CONFIDENCE...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..WEAK SURFACE LOW TRACKING NORTH OF THE GREAT LAKES TODAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE GUIDANCE SHOWS SIMILARLY WITH THIS SYSTEM.
...SHORTWAVE(S) SHEARING INTO THE INTERIOR NORTHWEST AND JOINING
WITH AN AMPLIFYING MID-LEVEL TROUGH AXIS INTO THE NORTH-CENTRAL
U.S. FOR MONDAY...
..SURFACE LOW IN THE VICINITY OF NEW ENGLAND TUESDAY MORNING
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z NAM, 00Z GFS, 12Z ECMWF BLEND
CONFIDENCE: AVERAGE
ENSEMBLE HAS SHOWN CONVERGENCE OVER ITS PAST FOUR 12/00Z CYCLES
BUT SOME TIMING AND AMPLITUDE DIFFERENCES REMAIN WITH THE 500 MB
TROUGH CROSSING THE NORTH-CENTRAL U.S. AND GREAT LAKES EARLY NEXT
WEEK. THE 00Z GFS IS SLIGHTLY MORE PROGRESSIVE WITH THE 500 MB
TROUGH, BUT FLOW DOWNSTREAM LACKS A BLOCKING RIDGE WHICH MAY
SUPPORT A MORE PROGRESSIVE TRACK TO THE UPPER TROUGH. THE 12Z
ECMWF AND 00Z NAM ARE MORE SIMILAR WITH A SLOWER TROUGH, NAM MORE
AMPLIFIED, BUT THE NAM'S SURFACE LOW NEAR THE NEW ENGLAND COAST
TUESDAY MORNING IS DISPLACED SLIGHTLY SOUTH/EAST OF THE CENTROID
OF THE LATEST ENSEMBLE SCATTER LOW PLOTS. THE 12Z ECMWF IS NEAR
THE MIDDLE OF THE LATEST SCATTER LOW PLOTS. MEANWHILE, THE 12Z
UKMET WAS A BIT FLATTER WITH THE UPPER TROUGH EARLIER IN THE
PERIOD ACROSS THE CENTRAL U.S. AND THE 12Z CMC IS THE SLOWEST/MOST
AMPLIFIED WITH THE UPPER TROUGH.
..COLD FRONT NEARING THE PACIFIC NORTHWEST ON TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z NAM/00Z GFS BLEND
CONFIDENCE: AVERAGE
TIMING DIFFERENCES APPEAR STARTING MONDAY MORNING AS A COLD FRONT
APPROACHES THE PACIFIC NORTHWEST. THE 12Z UKMET IS SLOWEST WHILE
THE 12Z ECMWF IS FASTEST WITH THE RELATED UPPER LEVEL TROUGH. THE
00Z NAM/00Z GFS APPEAR TO MAKE UP A REASONABLE COMPROMISE IN THE
MIDDLE OF THE LATEST SPREAD.
..CLOSED LOW OVER NORTHWESTERN MEXICO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
SOME MINOR TIMING DIFFERENCES EXIST WITH THIS FEATURE WITH THE 00Z
GFS/12Z UKMET FASTEST AND 12Z CMC SLOWEST. ENSEMBLE MEANS ARE IN
THE MIDDLE, AND ACTUALLY, THE DIFFERENCES BETWEEN THE
DETERMINISTIC GUIDANCE ARE SMALL ENOUGH THROUGH TUESDAY TO SUPPORT
A GENERAL MODEL BLEND FOR THE PREFERENCE.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
OTTO
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