890
FXUS10 KWNH 110525
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
125 AM EDT SAT JUL 11 2020
VALID JUL 11/0000 UTC THRU JUL 14/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z NAM/GFS EVALUATION WITH PRELIMINARY PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-LEVEL SHORTWAVE CROSSING THE GREAT LAKES/OHIO VALLEY
THROUGH SAT...
..ASSOCIATED COLD FRONT CROSSING THE GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON 12Z UKMET BLEND
CONFIDENCE: AVERAGE
THE MODELS SHOW MINOR DIFFERENCES IN THE TIMING AND STRENGTH OF
THE LOW TO MID-LEVEL WAVE ADVANCING THROUGH THE NORTHEAST
TODAY/SATURDAY NIGHT. THE ONE EXCEPTION IS THE 12Z UKMET HAS A
STRONGER DEPICTION OF THE 700-500 MB LOW WHICH IS UNSUPPORTED IN
THE REMAINING GUIDANCE. OTHERWISE, A BLEND (EXCLUDING THE 12Z
UKMET) LOOKS BEST HERE.
..TROPICAL STORM FAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS, 12Z ECMWF 12Z UKMET BLEND IS CLOSEST TO 03Z
NHC ADVISORY
CONFIDENCE: REFER TO NHC DISCUSSION
THE LATEST GUIDANCE IS IN GOOD AGREEMENT CONCERNING THE TRACK OF
FAY UNTIL LATE SATURDAY WHEN THE 00Z NAM DEVIATES WEST OF THE NHC
TRACK, WHILE THE 12Z CMC SLOWS DOWN. THE 00Z GFS, 12Z ECMWF AND
12Z UKMET SHOW DECENT AGREEMENT WITH ONE ANOTHER AND THE 03Z NHC
ADVISORY FOR THE TRACK OF FAY.
...MID-LEVEL SHORTWAVE TO CROSS THE NORTHERN PLAINS TO UPPER MS
VALLEY SAT, OHIO VALLEY SUNDAY,
GREAT LAKES TO THE APPALACHIANS MONDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NEAR THE 12Z ECMWF/12Z ECMWF MEAN
CONFIDENCE: AVERAGE
THE MODELS BEGIN TO DIVERGE WITH THE TIMING OF THE TROUGH AS IT
REACHES THE OH VALLEY. THE 00Z NAM AND 00Z GFS ARE FASTER,
ESPECIALLY THE 00Z GFS WHEN COMPARED TO THE REMAINING
DETERMINISTIC GUIDANCE AND THE GEFS/ECMWF MEANS. THE 12Z UKMET IS
SLOWEST WHILE THE 12Z CMC IS ALSO A BIT SLOW. THERE IS A MODERATE
AMOUNT OF SPREAD IN THE LATEST ENSEMBLE SPAGHETTI HEIGHT PLOTS,
BUT THE 12Z ECMWF MEAN APPEARS TO BE A DECENT REPRESENTATION OF
THE MIDDLE OF THE LATEST SPREAD WITH THE 12Z ECMWF NEAREST TO ITS
ENSEMBLE MEAN.
...LONGWAVE TROUGH AXIS MOVING INTO WESTERN CANADA AND THE
NORTHWESTERN U.S. ON SUN...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS, 12Z ECMWF, 12Z UKMET BLEND
CONFIDENCE: AVERAGE
THE MODELS SHOW A BROAD 500 MB TROUGH AND ASSOCIATED SURFACE COLD
FRONT MOVING ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES
SUNDAY TO SUNDAY NIGHT AND NORTHERN PLAINS MONDAY. MAINLY MINOR
TIMING DIFFERENCES WERE NOTED IN THE LATEST GUIDANCE, BUT THE 00Z
NAM AND 12Z CMC DIFFER WITH THE CORE OF THE CLOSED LOW THAT TRACKS
THROUGH ALBERTA AND SASKATCHEWAN WHEN COMPARED TO THE REMAINING
DETERMINISTIC AND ENSEMBLE MEAN GUIDANCE.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
THIS PRODUCT WILL TERMINATE AUGUST 15, 2020:
WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERMINATION.
OTTO
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