195
FXUS10 KWNH 020505
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
104 AM EDT SUN AUG 02 2020
VALID AUG 02/0000 UTC THRU AUG 05/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..MID-LEVEL TROUGH DIGGING ACROSS OH/TN VALLEYS
..SURFACE LOW CROSSING THE LOWER GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
MID-LEVEL TROUGHING OVER THE OH/TN VALLEYS WILL LIFT NORTHEAST AND
DRIVE A SURFACE LOW ACROSS THE LOWER GREAT LAKES REGION ON SUNDAY
BEFORE THEN ADVANCING INTO SOUTHEAST CANADA. THERE IS SOME MODEST
SPREAD WITH THE TRACK OF THE SURFACE LOW AS THE 00Z NAM/GFS
SOLUTIONS ARE A TAD LEFT OF THE 12Z NON-NCEP MODEL GUIDANCE, BUT
THERE IS SUFFICIENT CLUSTERING THAT A GENERAL MODEL BLEND CAN BE
PREFERRED WITH THIS ENERGY.
..HURRICANE ISAIAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 03Z NHC ADVISORY PACKAGE
BEST MODEL PROXY: CLOSEST TO THE 00Z GFS
THE 03Z NHC FORECAST TRACK OF HURRICANE ISAIAS IS OVERALL CLOSEST
TO THE 00Z GFS, BUT AFTER ABOUT 48 HOURS, THE GFS ENDS UP BEING
SOMEWHAT FASTER THAN THE NHC TRACK. THE 00Z NAM/12Z UKMET AND 12Z
ECMWF ALL END UP BEING SLOWER AS THE SYSTEM MAKES A LANDFALL
ACROSS EASTERN SC AND SOUTHERN NC, AND THEN NORTHEASTWARD ACROSS
THE REMAINDER OF THE MID-ATLANTIC COASTAL PLAIN GOING THROUGH 72
HOURS. THE 12Z CMC FOR ITS PART IS EVEN FASTER THAN THE GFS, AND
ENDS UP LEFT OF THE NHC TRACK. ALL OF THE MODELS SUPPORT THE
SYSTEM RAPIDLY LIFTING THROUGH NEW ENGLAND BY THE END OF THE
PERIOD. PLEASE CONSULT THE LATEST NHC FORECAST ADVISORY PACKAGE
FOR MORE DETAILS.
..NORTHERN STREAM TROUGH SETTING UP OVER THE GREAT LAKES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 60 HOURS
NON-GFS BLEND...AFTER 60 HOURS
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
NORTHERN STREAM ENERGY WILL BE DIGGING DOWN ACROSS THE GREAT LAKES
THROUGH SUNDAY WITH LIKELY DEVELOPMENT OF AN ELONGATED CLOSED LOW
A BIT FARTHER NORTH OVER ONTARIO BY MONDAY AND TUESDAY. BY THE END
OF THE PERIOD, THE 00Z GFS ENDS UP WITH A CLOSED LOW NORTH OF THE
MODEL CONSENSUS OVER ONTARIO. THE GUIDANCE IS AT LEAST IN GOOD
AGREEMENT THROUGH 60 HOURS, AND SO A GENERAL MODEL BLEND WILL BE
PREFERRED TO THAT POINT, FOLLOWED THEREAFTER BY A NON-GFS BLEND.
..UPPER LOW/TROUGH APPROACHING THE PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/GFS
CONFIDENCE: AVERAGE
AN UPPER TROUGH WILL CROSS IN THROUGH BRITISH COLUMBIA AND THE
PACIFIC NORTHWEST LATE ON SUNDAY AND THEN WELL INLAND THROUGH
MONDAY AND TUESDAY WITH THE MAIN FOCUS OF THE HEIGHT FALLS
REMAINING ACROSS WESTERN AND CENTRAL CANADA. HOWEVER, THE GUIDANCE
SUPPORT SOME ENERGY IN THE BASE OF THE TROUGH SEPARATING OUT
ACROSS THE FAR NORTHERN ROCKIES AND THEN ADVANCING SOUTHEAST BY
WEDNESDAY ACROSS THE NORTHERN PLAINS AND MIDWEST. THE 00Z NAM AND
00Z GFS ARE ON THE STRONGER SIDE OF THE GUIDANCE WITH THIS ENERGY
OVER THE NORTHERN U.S. LATE IN THE PERIOD. THE 12Z CMC/ECMWF
SOLUTIONS ARE WEAKER AND FASTER, WITH THE 12Z UKMET SLOWER. THE
PREFERENCE WILL BE TOWARD THE NAM/GFS CAMP FOR THE TIME BEING
SINCE THERE IS A BIT OF A TREND TOWARD STRONGER ENERGY SEPARATING
OUT FROM THE TROUGHING OVER CENTRAL CANADA.
..SOUTHERN STREAM TROUGH MOVING INTO CA BY WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A SOUTHERN STREAM TROUGH IS FORECAST BY THE MODELS TO MOVE IN OFF
THE PACIFIC OCEAN BY EARLY WEDNESDAY AND CROSS MUCH OF CALIFORNIA.
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE DETAILS OF THIS
SYSTEM, SO A GENERAL MODEL BLEND WILL 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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