657
FXUS10 KWNH 120701
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 AM EDT SUN JUL 12 2020
VALID JUL 12/0000 UTC THRU JUL 15/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH FINAL PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-LEVEL SHORTWAVE TROUGHING OVER THE NORTHEASTERN QUARTER OF
THE U.S. MONDAY TO WEDNESDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 00Z NAM, 00Z GFS AND 00Z UKMET
CONFIDENCE: AVERAGE
AFTER THE DEPARTURE OF A COMPACT VORTICITY MAX FROM THE NORTHEAST
EARLY TODAY/SUNDAY, A PAIR OF SHORTWAVES WILL APPROACH THE REGION
FROM THE WEST, HELPING TO REINFORCE UPPER LEVEL TROUGHING OVER THE
REGION INTO THE MIDDLE OF THE WEEK.
THE LATEST GUIDANCE SHOWS GOOD AGREEMENT WITH THE FIRST SHORTWAVE
EXPECTED TO REACH THE MID-ATLANTIC REGION BY MONDAY MORNING, BUT
DIFFERENCES BEGIN TO SHOW UP WITH A COMPACT MID-LEVEL CLOSED LOW
APPROACHING NEW YORK LATE MONDAY. THE 00Z ECMWF IS THE SLOWEST
WHILE 00Z CMC MORE PROGRESSIVE THAN THE FAVORED MIDDLE GROUND
SUPPORTED BY THE 00Z NAM/GFS/UKMET AND THE LATEST ENSEMBLE MEANS.
ENSEMBLE SPAGHETTI HEIGHT PLOTS SHOW A FAIR DEGREE OF
POSSIBILITIES BUT THE BEST CLUSTERING IS IN THE MIDDLE OF THE
FASTER AND SLOWER SOLUTIONS.
...LONGWAVE TROUGH AXIS MOVING THROUGH WESTERN CANADA AND THE
NORTHWESTERN/NORTH-CENTRAL U.S. THROUGH WEDNESDAY MORNING..
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND WEIGHTED TOWARD 00Z NAM/ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODELS SHOW GOOD OVERALL AGREEMENT WITH A BROAD 500 MB TROUGH
AND ASSOCIATED SURFACE COLD FRONT MOVING ACROSS THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES SUNDAY AND NORTHERN PLAINS MONDAY.
SOME MINOR TIMING DIFFERENCES WERE SEEN, WITH THE 00Z GFS A BIT
FASTER AND 00Z NAM A LITTLE SLOWER. THE 00Z NAM/ECMWF REPRESENT
THE BEST MIDDLE GROUND, BUT THE DIFFERENCES AMONG THE REMAINING
MODELS ARE SMALL ENOUGH TO SUPPORT A GENERAL MODEL BLEND FOR THE
PREFERENCE.
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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