674
FXUS10 KWNH 050632
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
230 AM EDT WED AUG 05 2020
VALID AUG 05/0000 UTC THRU AUG 08/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..LONGWAVE TROUGH FROM THE GREAT LAKES TO THE GULF COAST
..CLOSED MID LEVEL LOW OVER ONTARIO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODEL GUIDANCE IS REASONABLY WELL CLUSTERED WITH THE BROAD
LONGWAVE TROUGH TRACKING ACROSS THE EASTERN U.S., AND WEAKENING AS
IT DOES SO. OTHERWISE, THERE IS GENERALLY GOOD MODEL AGREEMENT AND
CONTINUITY WITH THE EVOLUTION OF THE CLOSED MID-LEVEL LOW CENTER
AS IT CROSSES ONTARIO INTO QUEBEC BEFORE REACHING NEWFOUNDLAND BY
THURSDAY. BASED ON THE ABOVE, A GENERAL MODEL BLEND IS AGAIN
PREFERRED.
..SHORTWAVE CROSSING THE NORTHERN PLAINS/UPPER MIDWEST
..ENERGY LIFTING INTO THE NORTHEAST BY SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS ARE IN VERY GOOD AGREEMENT TAKING SHORTWAVE ENERGY
CURRENTLY OVER SOUTHERN MANITOBA DOWN TO THE SOUTHEAST ACROSS
NORTHERN PLAINS ON WEDNESDAY BEFORE THEN TRACKING IT ACROSS THE
UPPER MIDWEST AND GREAT LAKES REGION GOING THROUGH THURSDAY. ON
FRIDAY, THE ENERGY SHOULD THEN BEGIN TO LIFT UP ACROSS THE
NORTHEAST. THE MODEL SPREAD IS RATHER MINIMAL THROUGH MOST OF THE
PERIOD, ALTHOUGH THE 00Z NAM/GFS/CMC SOLUTIONS ARE A TAD FASTER
THAN THE 00Z UKMET/ECMWF SOLUTIONS AS THE ENERGY ARRIVES ACROSS
THE NORTHEAST BY SATURDAY. FOR NOW, A GENERAL MODEL BLEND WILL
STILL BE PREFERRED.
..SOUTHERN STREAM TROUGH MOVING INTO CA
..CLOSED LOW DEVELOPMENT BY FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS ARE IN GOOD AGREEMENT BRINGING A BROAD UPPER TROUGH AND
HINTS OF A CLOSED MID-LEVEL CIRCULATION IN ACROSS NORTHERN CA ON
WEDNESDAY. GRADUALLY THE TROUGH WILL ADVANCE FARTHER SOUTH, BUT
THERE WILL BE ADDITIONAL UPSTREAM SHORTWAVE ENERGY OFFSHORE THAT
SHOULD MAINTAIN A TROUGH AXIS OVER CA THROUGH THE PERIOD,
INCLUDING LIKELY DEVELOPMENT OF A CLOSED MID-LEVEL LOW CENTER NEAR
OR JUST OFFSHORE OF CENTRAL CA BY LATE FRIDAY. SUFFICIENT MODEL
AGREEMENT EXISTS AT THIS POINT TO SUPPORT A GENERAL MODEL BLEND.
..MID-LEVEL TROUGH CROSSING THE PACIFIC NORTHWEST
..CLOSED LOW DEVELOPMENT OVER ALBERTA/SASKATCHEWAN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS/UKMET/ECMWF
CONFIDENCE: AVERAGE
THE MODELS ARE IN VERY GOOD AGREEMENT IN TAKING AN EVOLVING
LONGWAVE TROUGH FROM THE BRITISH COLUMBIA/PACIFIC NORTHWEST COAST
EARLY THURSDAY INTO SOUTHERN ALBERTA BY EARLY FRIDAY. AS IT DOES
SO, THE MID-LEVEL TROUGH WILL BE TAKING ON A NEGATIVE TILT AND
AMPLIFYING WITH THE EXPECTATION OF A CLOSED LOW CENTER FORMING
OVER SOUTHERN ALBERTA FRIDAY BEFORE THEN ADVANCING EAST INTO
SASKATCHEWAN. THE 00Z NAM ENDS UP A TAD FARTHER SOUTH WITH ITS
TROUGH AXIS AND CLOSED LOW EVOLUTION. THE 00Z CMC IS ALSO FARTHER
SOUTH BUT IS A TAD SLOWER. THE 00Z GFS/UKMET/ECMWF SOLUTIONS ALL
TAKE THEIR ENERGY A TAD NORTH OF THE MODEL CONSENSUS, WITH THE GFS
SOMEWHAT ON THE SLOWER SIDE OF THE GUIDANCE. THE LATEST GEFS MEAN
AND ECENS MEAN FAVOR THE RELATIVELY DECENT CLUSTERING OF THE
GFS/UKMET AND ECMWF, SO A BLEND OF THESE SOLUTIONS WILL BE
PREFERRED.
..SURFACE LOW DEVELOPMENT OVER THE CENTRAL PLAINS SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP BY SATURDAY ALONG A
FRONT OVER THE CENTRAL PLAINS. THE GUIDANCE IS NOW IN SUFFICIENT
AGREEMENT THAT A GENERAL MODEL BLEND CAN BE PREFERRED.
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.
ORRISON
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