630
FXUS10 KWNH 051827
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
227 PM EDT WED AUG 05 2020
VALID AUG 05/1200 UTC THRU AUG 09/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..LONG WAVE TROUGH FROM THE GREAT LAKES TO THE GULF COAST
..CLOSED MID LEVEL LOW OVER ONTARIO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
BOTH THE 12Z NAM/GFS ARE CLOSE TO THE TIGHT CLUSTERING TAKING THE
LONG WAVE TROUGH EXTENDING FROM THE GREAT LAKES TO THE GULF COAST
EASTWARD, WEAKENING IT WITH TIME AS THE MID LEVEL RIDGING OVER THE
ATLANTIC SLIDES TO THE EAST. WHILE THE 12Z GFS BECOMES A BIT
SLOWER WITH THE NORTHERN END OF THE TROUGH OVER NEW ENGLAND AFTER
08/12Z, THE DIFFERENCE IS MINOR, AND A GENERAL MODEL BLEND IS
PREFERRED WITH ABOVE AVERAGE FORECAST CONFIDENCE.
..SHORT WAVE CROSSING THE NORTHERN PLAINS/UPPER GREAT LAKES
..ENERGY LIFTING INTO THE NORTHEAST SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE 12Z NAM/GFS ARE IN LOCK STEP WITH THE MODEL CONSENSUS TAKING
SHORT WAVE ENERGY OVER ND THIS AFTERNOON ACROSS THE UPPER GREAT
LAKES THROUGH 08/00Z, THEN TRACKING IT ACROSS NEW ENGLAND BY
09/00Z. CONSIDERING THE TIGHT CLUSTERING WITH THIS FEATURE, A
GENERAL MODEL BLEND IS PREFERRED WITH ABOVE AVERAGE FORECAST
CONFIDENCE.
..SOUTHERN STREAM TROUGH MOVING INTO CA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
SHORT WAVE ENERGY OVER NORTHERN CA THIS AFTERNOON AND EVENING
DROPS INTO AN EVOLVING LONG WAVE TROUGH FORMING OVER CA THROUGH
07/12Z. ADDITIONAL SHORT WAVE ENERGY DROPPING INTO THE BACK OF THE
TROUGH PULLS THE LONG WAVE TROUGH AXIS JUST OFFSHORE OF THE CA
COAST. EVENTUALLY, THE LONG WAVE TROUGH WEAKENS, POSSIBLY LEAVING
AN ISOLATED CLOSED MID LEVEL LOW OFF THE SOUTHWEST CA COAST BY
09/00Z. ONCE AGAIN, THERE IS LITTLE SPREAD IN THE MODEL GUIDANCE
IN THE DEVELOPMENT OF THE LONG WAVE TROUGH (THOUGH THERE IS SOME
SPREAD CONCERNING THE DEVELOPMENT OF A CLOSED MID LEVEL LOW THIS
EVENING OVER NORTHERN CA). WITH THIS IN MIND, A GENERAL MODEL
BLEND IS PREFERRED, WITH ABOVE AVERAGE FORECAST CONFIDENCE.
..LONG WAVE TROUGH CROSSING THE PACIFIC NORTHWEST
..CLOSED LOW DEVELOPMENT OVER SASKATCHEWAN/MANITOBA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE 12Z NAM/GFS ARE CLOSE TO THE MODEL CONSENSUS TRACKING A LONG
WAVE TROUGH ACROSS THE PACIFIC NORTHWEST BY 07/00Z, WHICH TAKES ON
A NEGATIVE TILT AS IT REACHES EAST CENTRAL ALBERTA BEFORE 08/00Z.
AFTER THIS TIME, THERE IS SOME MODEL SPREAD CONCERNING THE
EVOLUTION OF DEVELOPMENT OF A CLOSED MID LEVEL LOW OVER CENTRAL
SASKATCHEWAN TOWARD 08/12Z. THE 12Z NAM/GFS ARE CLOSE TO THE
CONSENSUS PLACING A CLOSED MID LEVEL LOW OVER NORTHERN MANITOBA
(THOUGH THE 12Z GFS DOES NOT KEEP THE SYSTEM CLOSED). THE 12Z CMC
HAS SPED UP ITS SOLUTION, PLACING IT CLOSE TO THE CONSENSUS
(THOUGH IT DOES NOT CLOSE OFF A MID LEVEL CENTER).
WHILE THERE IS SOME MINOR MODEL SPREAD WITH THE PLACEMENT OF THE
CLOSED LOW BY 09/00Z, THE OVERALL MODEL AGREEMENT IS CLOSE ENOUGH
TO SUPPORT A MULTI MODEL BLEND. WITH THE 12Z CMC COMING INTO LINE
WITH THE REMAINDER OF THE 12Z SOLUTIONS, FORECAST CONFIDENCE IS
ONCE AGAIN ABOVE AVERAGE.
..SURFACE LOW DEVELOPMENT OVER THE CENTRAL PLAINS SAT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THERE IS GOOD MODEL AGREEMENT WITH THE DEVELOPMENT OF SURFACE LOW
PRESSURE OVER WESTERN KS/SOUTHWEST NE AFTER 08/12Z, THOUGH THERE
IS SOME SPREAD WITHIN THE INDIVIDUAL 00Z ECMWF ENSEMBLE AND 12Z
GEFS MEMBERS. FROM THIS DISTANCE, THE SPREAD APPEARS TO BE BE
FAIRLY NEGLIGIBLE, SO A GENERAL MODEL BLEND IS PREFERRED WITH
ABOVE AVERAGE CONFIDENCE.
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.
HAYES
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