156
FXUS10 KWNH 241854
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
254 PM EDT FRI JUL 24 2020
VALID JUL 24/1200 UTC THRU JUL 28/0000 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 TRACKING FROM THE NORTHWEST INTO THE
NORTH-CENTRAL U.S. THROUGH THE WEEKEND...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A MID-LEVEL CLOSED LOW/SHORTWAVE TROUGH WILL TRACK THROUGH
SOUTHWESTERN CANADA THROUGH SATURDAY WITH A COLD FRONT AT THE
SURFACE AND EXTENDING INTO THE NORTHWESTERN U.S. AS THIS ENERGY
REACHES THE NORTHERN PLAINS LATE IN THE WEEKEND, IT WILL PHASE
WITH SOME SOUTHERN STREAM ENERGY LIFTING THROUGH THE FRONT RANGE
AND CENTRAL PLAINS, WHICH WILL ALLOW THE TROUGH TO DEEPEN OVER THE
NORTHERN PLAINS AND UPPER MIDWEST. THE LATEST GUIDANCE HAS COME
INTO VERY GOOD AGREEMENT AND CLUSTERS WELL ENOUGH THAT A GENERAL
MODEL BLEND WILL BE PREFERRED THROUGH THE PERIOD.
..TROPICAL STORM HANNA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: OFFICIAL NHC TRACK
BEST MODEL PROXY: 12Z GFS/UKMET/ECMWF BLEND
CONFIDENCE: SEE LATEST NHC PRODUCTS
THE LATEST MODEL GUIDANCE CONTINUES TO SHOW FAIRLY GOOD CLUSTERING
WITH THE TRACK AND SPEED OF THE T.S. HANNA OVER THE NEXT 24 HOURS
AS THE SYSTEM APPROACHES AND ULTIMATELY MAKES A LANDFALL ALONG THE
SOUTH-CENTRAL TEXAS COASTLINE. THE 12Z GFS, 12Z UKMET AND 12Z
ECMWF ARE QUITE CLOSE OR PERHAPS LOCALLY A TAD SOUTH OF THE 15Z
NHC TRACK OF HANNA, WITH THE 12Z NAM AND 12Z CMC A BIT FARTHER
NORTH AND A TAD FASTER LEADING UP TO LANDFALL. SOME STRENGTHENING
OF THE MID-LEVEL SUBTROPICAL RIDGE NORTH OF HANNA SHOULD STEER THE
SYSTEM MORE WESTWARD BY SATURDAY AND THEN WEST-SOUTHWESTWARD
SATURDAY NIGHT AS THE SYSTEM CROSSES THROUGH THE LOWER RIO GRANDE
VALLEY. ON SUNDAY, HANNA SHOULD BE WEAKENING OVER NORTHEAST MEXICO.
..UPPER LOW/TROUGH OVER CALIFORNIA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A BROAD UPPER TROUGH AND EMBEDDED CLOSED LOW OVER CA WILL
GENERALLY REMAIN IN PLACE THROUGH EARLY NEXT WEEK, WITH SOME
TENDENCY FOR THE ENERGY TO BEGIN LIFTING NORTH BY THE END OF THE
PERIOD. OVERALL, THE MODELS ARE IN GOOD AGREEMENT THROUGH THE
PERIOD WITH THE HANDLING OF THIS ENERGY, 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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