488
FXUS10 KWNH 050426
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1225 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 SOLUTIONS ARE A TAD FASTER THAN
THE 12Z NON-NCEP MODELS 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: NON-UKMET 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. THE 12Z UKMET TENDS
TO HAVE A MORE ELONGATED MID-LEVEL LOW CENTER OFFSHORE OF CA BY
THE END OF THE PERIOD. THE REMAINING GUIDANCE IS WELL CLUSTERED ON
A MORE SYMMETRICAL FEATURE, SO A NON-UKMET BLEND WILL BE PREFERRED
WITH THIS ENERGY.
..MID-LEVEL TROUGH CROSSING THE PACIFIC NORTHWEST
..CLOSED LOW DEVELOPMENT OVER ALBERTA/SASKATCHEWAN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS AND 12Z CMC
CONFIDENCE: SLIGHTLY ABOVE 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. MEANWHILE, THE 12Z UKMET IS
GENERALLY THE FARTHEST NORTH WITH THE ENERGY. THE 00Z GFS, 12Z CMC
AND 12Z ECMWF ARE BETTER CLUSTERED, ALTHOUGH THE ECMWF MAY BE A
TAD TOO FAST AS ITS ENERGY CROSSES SOUTHERN CANADA BY LATE IN THE
PERIOD. THE LATEST GEFS MEAN AND ECENS MEAN FAVOR THE GFS/CMC
CLUSTER A BIT MORE OVERALL, SO A GFS/CMC BLEND WILL BE PREFERRED
WITH THIS TROUGH.
..SURFACE LOW DEVELOPMENT OVER THE CENTRAL PLAINS SATURDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: ABOVE AVERAGE
AN AREA OF LOW PRESSURE IS EXPECTED TO DEVELOP BY SATURDAY ALONG A
FRONT OVER THE CENTRAL PLAINS. THE 12Z CMC APPEARS TO BE A TAD TOO
FAR EAST WITH ITS FRONT AND LOW CENTER PLACEMENT. THE REMAINING
GUIDANCE IS REASONABLY WELL CLUSTERED A BIT FARTHER BACK TO THE
WEST, SO A NON-CMC BLEND WILL BE PREFERRED FOR THE TIME BEING
REGARDING THE SURFACE LOW AND FRONT.
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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