069
FXUS10 KWNH 251844
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
243 PM EDT SAT JUL 25 2020
VALID JUL 25/1200 UTC THRU JUL 29/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..MID-UPPER LEVEL TROUGHING OVER THE NORTHERN CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 60 HOURS
NON-NAM BLEND...AFTER 60 HOURS
CONFIDENCE: ABOVE AVERAGE
A MID TO UPPER-LEVEL TROUGH OVER THE NORTHWEST AND ADJACENT AREAS
OF SOUTHWEST CANADA WILL ADVANCE EAST THROUGH EARLY NEXT WEEK AND
GRADUALLY AMPLIFY OVER PORTIONS OF THE MIDWEST AND GREAT LAKES
REGION GOING THROUGH TUESDAY. IN FACT, ALL OF THE MODELS SHOW A
WELL-DEVELOPED UPPER LOW JUST TO THE NORTH OVER ONTARIO BY THE END
OF THE PERIOD. THE MODEL GUIDANCE IS REASONABLY WELL CLUSTERED
WITH THE TIMING AND EVOLUTION OF THIS ENERGY ALONG WITH THE
ATTENDANT COLD FRONT CROSSING PORTIONS OF THE PLAINS, MIDWEST AND
EVENTUALLY THE EASTERN U.S. HOWEVER, AFTER ABOUT 60 HOURS, THE 12Z
NAM DOES APPEAR TO BE A TAD TOO FAR NORTH WITH ITS ORIENTATION OF
THE TROUGH AND CLOSED LOW. THE GLOBAL MODELS AND ENSEMBLE MEANS
ARE WELL CLUSTERED A TAD FARTHER SOUTH. SO, A GENERAL MODEL BLEND
WILL BE PREFERRED THROUGH 60 HOURS, FOLLOWED BY A NON-NAM BLEND
THEREAFTER.
..HURRICANE HANNA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: OFFICIAL NHC TRACK
BEST MODEL PROXY: 12Z NAM/GFS BLEND
CONFIDENCE: SEE LATEST NHC PRODUCTS
HURRICANE HANNA WILL MAKE LANDFALL ALONG THE SOUTH TEXAS COAST
THIS AFTERNOON AND ACROSS DEEP SOUTH TEXAS TONIGHT BEFORE CROSSING
INTO NORTHEAST MEXICO EARLY ON SUNDAY. THE 12Z NAM/GFS SOLUTIONS
APPEAR GENERALLY TO BE THE CLOSEST TO THE 15Z NHC FORECAST TRACK.
THE 12Z UKMET BECOMES A BIT OF A FASTER OUTLIER SOLUTION BY THIS
EVENING AND OVERNIGHT AND IS ALSO NOW A TAD NORTH OF THE NHC
TRACK. THE 12Z CMC/ECMWF SOLUTIONS ARE ALSO BOTH A LITTLE NORTH OF
THE NHC TRACK. FOR THE LATEST INFORMATION ON HANNA, PLEASE CONSULT
THE LATEST NHC PUBLIC ADVISORY.
..UPPER TROUGH/LOW OVER CALIFORNIA/GREAT BASIN
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A BROAD UPPER TROUGH AND EMBEDDED CLOSED LOW OVER CA WILL
GENERALLY REMAIN IN PLACE OVER THE NEXT COUPLE OF DAYS, BUT SHOULD
THEN GRADUALLY ADVANCE NORTHEAST AND WEAKEN THROUGH THE GREAT
BASIN BY TUESDAY. OVERALL, THE MODELS ARE IN GOOD AGREEMENT
THROUGH THE PERIOD WITH THE HANDLING OF THIS ENERGY, SO A GENERAL
MODEL BLEND WILL BE PREFERRED.
..NEW UPPER TROUGH/LOW APPROACHING CALIFORNIA BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: ABOVE AVERAGE
A NEW UPPER TROUGH AND EMBEDDED CLOSED LOW WILL BE APPROACHING CA
BY LATE TUESDAY. THE 12Z CMC HAS TRENDED SLOWER WITH THIS SYSTEM,
BUT IT STILL IS A TAD MORE PROGRESSIVE THAN THE REMAINING SUITE OF
GUIDANCE WITH THIS SYSTEM. A NON-CMC BLEND WILL BE STILL BE
PREFERRED FOR THE TIME BEING.
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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