600
FXUS10 KWNH 100645
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
245 AM EDT MON AUG 10 2020
VALID AUG 10/0000 UTC THRU AUG 13/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...WEAK TROUGHING OVER THE SOUTHEASTERN U.S. TUESDAY AND WEDNESDAY.
PREFERENCE: 00Z GFS, 21Z SREF MEAN, 12Z UKMET BLEND
CONFIDENCE: AVERAGE
MODEL FORECASTS TAKE AN EXISTING MCV OVER THE LOWER OHIO VALLEY
FROM SUNDAY MORNING, SOUTHEASTWARD TOWARD THE CAROLINAS BY
WEDNESDAY MORNING INTO THE BASE OF A DEVELOPING TROUGH. THE MODELS
DIFFER IN STRENGTH REGARDING THIS FEATURE WITH MOST SHOWING A
TROUGH EAST OF THE APPALACHIANS ACROSS THE SOUTHEAST AND A FEW
MODELS HINT OF EMBEDDED 850 OR 700 MB CIRCULATION DEVELOPING
WITHIN THE BROAD TROUGH AXIS.
THE MODELS SHOW A WELL DEFINED CLOSED HIGH OVER THE ATLANTIC THAT
WILL ACT AS A BLOCKADE TO PREVENT THIS TROUGH FROM MOVING OFF THE
SOUTHEAST COAST.
THE GFS/NAM/UKMET SHOW BETTER THAN AVERAGE OVERLAP ON THE AXIS OF
THE 700 MB TROUGH, SUPPORTED BY THE 21Z SREF MEAN.
A BLEND OF THESE SOLUTIONS WOULD MITIGATE MINOR DIFFERENCES IN
TIMING/PHASING.
...MISSOURI AND ARKANSAS
PREFERENCE: 00Z GFS, 12Z ECMWF BLEND
CONFIDENCE: SLIGHTLY BELOW AVERAGE
THE MODELS SHOW A 700 MB RIDGE WITH POSSIBLE EMBEDDED HIGH MOVING
EAST FROM THE LOWER MS VALLEY INTO THE SOUTHEAST. A LOW LEVEL
FRONT AND 700 MB TROUGH/POSSIBLE EMBEDDED CIRCULATION MOVES EAST
FROM KANSAS TODAY INTO MO AND AR TUE.
THE MODELS DIFFERE ONT HE STRNGTH AND TIMING, WITH THE 00Z NAM
STRONGEST WITH A MORE PERSISTENT 700 MB LOW. THE 21Z SREF
WEAKENED THE WAVE QUICKEST. AN INTERMEDIATE SOLUTION LIKE THE 00Z
GFS/12Z ECMWF IS PREFERRED UNTIL BETTER AGREEMENT DEVELOPS.
..LONGWAVE TROUGHING OVER THE NORTHWEST TUESDAY-WEDNESDAY
PREFERENCE: BLEND OF 12Z ECMWF, 00Z UKMET, 00Z NAM
CONFIDENCE: AVERAGE
AS A BROAD MID-UPPER LEVEL TROUGH AXIS DEVELOPS OVER THE
NORTHWESTERN U.S. TUESDAY INTO WEDNESDAY, WEAK WAVES WILL EMANATE
AND PROGRESS ONTO THWE HIGH PLAINS TUE NIGHT AND MOVE ACROSS THE
NORTHERN PLAINS ON WED. FURTHER SOUTH, A LEE TROUGH DEVELOPS IN
CO TO NEAR THE KS BORDER.
THE 00Z GFS STANDS OUT WITH THE AMPLIFICATION OF A 700 MB WAVE
EJECTING NORTHEAST FROM SD ACROSS MN ON WED. AND NEAR THE WI/MN
BORDER BY LAKE SUPERIOR 00Z THU. CAUTION IS ADVISED WITH THE GFS
IN THE UPPER MS VALLEY.
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.
PETERSEN
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