539
FXUS10 KWNH 021018
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
618 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. THE MODELS ARE IN
GOOD AGREEMENT AND THUS A GENERAL MODEL BLEND WILL STILL BE
PREFERRED.
..TROPICAL STORM ISAIAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 03Z NHC ADVISORY PACKAGE
BEST MODEL PROXY: GFS/CMC/UKMET/ECMWF BLEND
THE 03Z NHC FORECAST TRACK OF TROPICAL STORM ISAIAS IS OVERALL
CLOSEST NOW TO A MULTI-MODEL BLEND CONSISTING OF THE 00Z GFS, 00Z
UKMET, 00Z CMC AND 00Z ECMWF. OF THESE SOLUTIONS, THE GFS AND CMC
END UP GENERALLY A LITTLE FASTER THAN THE NHC TRACK, ESPECIALLY
AFTER 48 HOURS, AND WITH THE UKMET AND ECMWF A LITTLE SLOWER. THE
ECMWF IS ALSO SEEN AS BEING A BIT LEFT OF THE NHC TRACK AS THE
SYSTEM MAKES A LANDFALL ACROSS EASTERN SC AND SOUTHERN NC, AND
THEN ADVANCES NORTHEASTWARD ACROSS THE REMAINDER OF THE
MID-ATLANTIC COASTAL PLAIN GOING THROUGH 72 HOURS. THE 00Z NAM FOR
ITS PART ENDS UP BEING THE SLOWEST AND FARTHEST WEST SOLUTION BY
THE END OF THE PERIOD. HOWEVER, 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 48 HOURS
00Z GEFS/12Z ECENS BLEND...AFTER 48 HOURS
CONFIDENCE: 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 AND 00Z ECMWF SUGGEST A CLOSED LOW
NORTH OF THE MODEL CONSENSUS OVER ONTARIO, WITH THE 00Z NAM
FARTHER SOUTH. THE 00Z CMC AND 00Z UKMET SPLIT THE DIFFERENCE, BUT
THE 00Z GEFS MEAN AND THE RECENT 12Z ECENS MEAN CLUSTER WELL AND
APPROXIMATE THE MODEL CONSENSUS. THE GUIDANCE IS AT LEAST IN GOOD
AGREEMENT THROUGH 48 HOURS, AND SO A GENERAL MODEL BLEND WILL BE
PREFERRED TO THAT POINT, FOLLOWED THEREAFTER BY A BLEND OF THE 00Z
GEFS MEAN AND YESTERDAY'S 12Z ECENS MEAN.
..UPPER LOW/TROUGH CROSSING THE PACIFIC NORTHWEST
..ENERGY DROPPING DOWN OVER THE NORTHERN PLAINS/MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/GFS/CMC
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
SUPPORTS 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 00Z ECMWF AND
ESPECIALLY THE 00Z UKMET ARE NOTABLY WEAKER. HOWEVER, THE 00Z CMC
HAS TRENDED TOWARD THE STRONGER NAM/GFS CAMP. IN FACT, THE NAM,
GFS AND CMC WOULD ALL SUPPORT A MID-LEVEL CLOSED LOW FEATURE
POTENTIALLY DROPPING SOUTHEAST ACROSS ND AT THE END OF THE PERIOD.
THE PREFERENCE WILL BE TOWARD THE NAM/GFS/CMC 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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