983
FXUS10 KWNH 101841
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
241 PM EDT FRI JUL 10 2020
VALID JUL 10/1200 UTC THRU JUL 14/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH PREFERENCES/CONFIDENCE
...MID-LEVEL SHORTWAVE CROSSING THE GREAT LAKES/OHIO VALLEY
THROUGH SAT...
..ASSOCIATED COLD FRONT CROSSING THE GREAT LAKES
PREFERENCE: BLEND OF THE 12Z ECMWF/12Z GFS/09Z SREF MEAN
CONFIDENCE: AVERAGE
THE MODELS DIFFER IN THE STRENGTH OF THE WAVE LEVEL WAVE AND SFC
LOW CROSSING THE LOWER LAKES SAT AND NORTHERN NY/NORTHERN NEW
ENGLAND THEREAFTER. THE 12Z UKMET BECOMES AND OUTLIER WITH A
SIGNIFICANTLY STRONGER LOW. THE 09Z SREF MEAN/00Z ECMWF ENSEMBLE
MEAN/12Z OPERATIONAL ECMWF/12Z GFS CLUSTER BETTER IN THIS AREA,
AND ARE PREFERRED.
NO SINGLE MODEL SOLUTION LOOKS IDEAL HERE, SO A BLEND OF THE 12Z
GFS/12Z ECMWF/09Z SREF MEAN IS PREFERRED.
..TROPICAL STORM FAY
PREFERENCE: SEE NHC ADVISORY TRACK
CONFIDENCE: REFER TO NHC DISCUSSION
THE 12Z UKMET/ECMWF ADJUSTED TO A FASTER TRACK, AND ARE NOW CLOSER
TO THE 15Z NHC ADVISORY FOR THE TRACK OF FAY. BEYOND SATURDAY
MORNING, THE MODELS HAVE COME INTO BETTER AGREEMENT WITH MOST NOW
CLOSE TO
THE NHC TRACK IN THE NORTHEAST.
THE 12Z GFS IS STILL A FASTER OUTLIER ONCE THE LOW DEPARTS UP INTO
CANADA. THE 12Z ECMWF/12Z NAM/12Z UKMET ARE CLOSER TO THE NHC
TRACK POSITIONS.
...MID-LEVEL SHORTWAVE TO CROSS THE NORTHERN PLAINS TO UPPER MS
VALLEY SAT, OHIO VALLEY SUNDAY,
GREAT LAKES TO THE APPALACHIANS MONDAY...
PREFERENCE: BLEND OF 12Z GFS/12Z ECMWF/09Z SREF MEAN
CONFIDENCE: AVERAGE
THE MODELS INDICATE AN AMPLIFYING 700 MB WAVE CROSSES FROM THE
NORTHERN PLAINS SAT INTO THE UPPER MS VALLEY, CONTINUING INTO THE
OHIO VALLEY SUN. THE 12Z NAM GETS AHEAD OF THE PACK BY A FEW
HOURS SUN-SUN NIGHT, WITH BETTER CLUSTERING TIMING-WISE AMONG THE
ECMWF/GFS AND THEIR RESPECTIVE ENSEMBLE MEANS.
THE 12Z UKMET HAS BACKED OFF THE PRIOR STRONGER LOW ON MONDAY IN
PA, SO THE 12Z RUN IS CLOSER TO THE 12Z GFS/00Z-12Z ECMWF. SINCE
THE 09Z SREF MEAN AGREES BETTER WITH THE ECMWF/GFS
TIMING/AMPLITUDE, WITH SUPPORT FROM THE GEFS MEAN TIMING, A BLEND
OF THESE SOLUTIONS IS PREFERRED.
...LONGWAVE TROUGH AXIS MOVING INTO WESTERN CANADA AND THE
NORTHWESTERN U.S. ON SUN...
PREFERENCE: BLEND OF 12Z GFS/12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODELS SHOW A BROAD 500 MB TROUGH AND ASSOCIATED SFC FRONT
MOVING ACROSS THE PACIFIC NORTHWEST AND NORTHERN ROCKIES SUNDAY TO
SUNDAY NIGHT AND NORTHERN PLAINS MONDAY. ONLY MINOR TIMING
ADJUSTMENTS WERE NOTED IN THE 12Z ECMWF/12Z UKMET/12Z GFS/12Z NAM.
GIVEN THE MINOR DIFFERENCES NOTED WITH THE LARGE SCALE TROUGH, A
GENERAL MODEL BLEND WILL WORK WELL HERE FOR THE PREFERENCE. THIS
AREA HAS GOOD RUN TO RUN CONTINUITY, SO CONFIDENCE IS SLIGHTLY
ABOVE AVERAGE.
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:
HTTPS://WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERM
INATION.PDF
PETERSEN
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