084
FXUS10 KWNH 130450
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1249 AM EDT THU AUG 13 2020
VALID AUG 13/0000 UTC THRU AUG 16/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z PRELIMINARY MODEL EVALUATION INCLUDING PREFERENCES AND
FORECAST CONFIDENCE
...LONGWAVE TROUGH MOVING FROM THE NORTHWEST TO THE WESTERN GREAT
LAKES...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GEFS/ECENS/NAM/CMC BLEND
CONFIDENCE: AVERAGE
AN UPPER LEVEL TROUGH WITH AN EMBEDDED STRENGTHENING VORT MAX
DIGGING THROUGH ITS BASE WILL MOVE FROM THE NW THROUGH THE WESTERN
GREAT LAKES BY SATURDAY. THE KEY FEATURE HERE IS THAT VORT MAX
WHICH MAY SPAWN A WAVE OF LOW PRESSURE AND WILL DRAG A COLD FRONT
EASTWARD BENEATH IT. OTHER THAN THE GFS, WHICH IS A BIT FAST, THE
TIMING ENVELOPE IS SMALL AMONG THE GLOBAL MODELS. HOWEVER, THE
ECMWF IS A SHALLOW SOLUTION COMPARED TO THE OTHER SOLUTIONS, WHILE
THE UKMET PRODUCES QPF WHICH IS QUITE A BIT HIGHER THAN ANY OTHER
SOLUTION. A COMPROMISE OF THE GEFS/ECENS/NAM/CMC LEAVES A
REASONABLE SOLUTION FOR THE PROGRESSION AND AMPLITUDE OF THIS
FEATURE, WITH HEAVY RAINFALL POSSIBLE ACROSS THE UPPER MIDWEST
ASSOCIATED WITH THIS TROUGH.
...LARGE TROUGH DEVELOPING ACROSS THE EASTERN CONUS THROUGH
SUNDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GEFS/ECENS/SREF/CMC
CONFIDENCE: BELOW AVERAGE
AN UPPER LEVEL TROUGH WILL GRADUALLY ENVELOP THE ENTIRE EASTERN
CONUS, WHILE A SHORTWAVE RIDGE BLOSSOMS INTO SOUTHERN CANADA. THIS
LEAVES A WEAKNESS IN THE HEIGHT FIELDS ACROSS THE OHIO VALLEY INTO
WHICH A SECONDARY TROUGH OR EVEN A CLOSED LOW MAY DEVELOP
SATURDAY. THERE CONTINUES TO BE QUITE A BIT OF SPREAD IN BOTH THE
AMPLITUDE OF THIS TROUGH, AND POSITION/INTENSITY OF THE MID-LEVEL
WAVE/CLOSED LOW DEVELOPING IN THE OHIO VALLEY. THERE ARE ALSO
SIGNIFICANT DIFFERENCES WHICH ARISE BY SATURDAY ACROSS NEW ENGLAND
OWING TO THE POSITION OF THE SHORTWAVE RIDGE AND ITS INTERACTION
WITH THE OH VLY FEATURE. THE DETERMINISTIC MODELS ARE ALL OVER THE
PLACE, BUT THE GEFS/SREF MEANS SUGGEST A RATHER SIMILAR EVOLUTION
SO ARE WEIGHTED HEAVILY IN THE BLEND. DESPITE BEING MORE SHALLOW,
THE ECENS HAS SHOWN DECENT CONSISTENCY, AND OF THE DETERMINISTIC
MODELS THE CMC IS THE ONE WHICH MOST CLOSELY RESEMBLES THE
PREFERENCES FROM THE MEANS. HOWEVER, AT THIS TIME THERE REMAINS
BELOW AVERAGE CONFIDENCE, AND WHILE A TROUGH ACROSS THE EAST SEEMS
LIKELY, ITS INTENSITY, AND WHERE THE SECONDARY LOW MAY DEVELOP TO
ENHANCE RAINFALL POTENTIAL, REMAIN QUITE UNCERTAIN.
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.
WEISS
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