431
FXUS10 KWNH 230650
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
250 AM EDT THU JUL 23 2020
VALID JUL 23/0000 UTC THRU JUL 26/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
07Z UPDATE: NO SIGNIFICANT CHANGES NOTED WITH THE REST OF THE 00Z
GUIDANCE AND NO CHANGES NEEDED TO THE MODEL BLEND PREFERENCES.
...BROAD GREAT LAKES TROUGH AXIS AND CORRESPONDING COLD FRONT
IMPACTING THE OH VALLEY, NORTHEAST AND MID-ATLANTIC INTO
SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
SHORTWAVE ENERGY WILL BRUSH PORTIONS OF THE NORTHEAST AND NEW
ENGLAND OVER THE NEXT 24 HOURS THEN GRADUALLY GIVE WAY TO ZONAL
FLOW AS HEIGHTS BUILD OVER THE CENTRAL US AND MID-MS RIVER VALLEY.
THE MODELS SHOW VERY GOOD AGREEMENT WITH THIS SYNOPTIC PATTERN AND
EVOLUTION AND A GENERAL MODEL BLEND IS SUFFICIENT.
..MID-UPPER LEVEL TROUGHING IMPACTING THE NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 24.12Z; BLEND OF
ECMWF/UKMET/ECENS AFTER
CONFIDENCE: AVERAGE
A SHORTWAVE TROUGH PUSHES THROUGH THE NORTHWEST THIS MORNING
FOLLOWED BY A STRONGER CLOSED LOW THAT SKIRTS WASHINGTON STATE AND
THE FAR NORTHERN ROCKIES OVER THE FORECAST PERIOD. THROUGH 36
HOURS, MODEL AGREEMENT IS VERY GOOD AND A GENERAL MODEL BLEND IS
SUFFICIENT. BEYOND THAT, AS THE CLOSED LOW OPENS UP, SOME TIMING
AND STRENGTH DIFFERENCES DEVELOP. THE NAM AND TO SOME DEGREE THE
GFS ARE THE STRONGER SOLUTIONS WHILE THE CMC IS FASTEST AND AHEAD
OF THE REST OF THE GUIDANCE. THE GFS IS ALSO A TAD FASTER COMPARED
TO THE REST OF THE DETERMINISTIC GUIDANCE AND MUCH FASTER THAN ITS
ENSEMBLE MEAN. FOR THESE REASONS, A BLEND OF THE ECMWF/UKMET/ECENS
IS PREFERRED.
..CALIFORNIA/SOUTHWEST U.S
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
A CLOSED LOW OVER CALIFORNIA WILL DROP TOWARD SOUTHERN NEVADA OVER
THE NEXT 24-36 HOURS BEFORE BEING ABSORBED INTO THE GENERAL
TROUGHING OVER THE WESTERN U.S. INTO DAY 2/3. AFTER THE DEPARTURE
OF THE CLOSED LOW FROM CA, ANOTHER DISTURBANCE (WEAKER THAN THE
PREVIOUS LOW) WILL REACH THE CA COAST LATE ON SATURDAY. ASIDE FROM
THE UKMET, THE MODELS SHOW VERY GOOD AGREEMENT IN THE SYNOPTIC
MASS FIELDS SUCH THAT A GENERAL MODEL BLEND SHOULD BE SUFFICIENT.
..TROPICAL DEPRESSION EIGHT
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: OFFICIAL NHC FORECAST
BEST MODEL PROXY: 12Z ECMWF
CONFIDENCE: AVERAGE
NHC INITIATED ADVISORIES ON NEWLY FORMED TROPICAL DEPRESSION EIGHT
AS OF 03Z ASSOCIATED WITH AN AREA OF LOW PRESSURE CURRENTLY OVER
THE CENTRAL GULF OF MEXICO. THE LATEST MODEL GUIDANCE SHOWS FAIRLY
GOOD AGREEMENT THAT THIS FEATURE WILL MOVE EASTWARD OVER THE NEXT
FEW DAYS, APPROACHING THE CENTRAL TEXAS GULF COAST BEFORE SLOWING
INLAND BY THE END OF THE PERIOD. THE GFS WAS THE MOST
DISORGANIZED/WEAK WITH THE SYSTEM AND WASN'T CONSIDERED THE BEST
PROXY AGAINST THE OFFICIAL NHC TRACK. THE REMAINING DETERMINISTIC
GUIDANCE, SPECIFICALLY THE 12Z ECMWF, WOULD BE GOOD PROXIES FOR
MODEL GUIDANCE. FOR TIMING PURPOSES, THE NHC TRACK IS SLOWER
COMPARED TO MOST OF THE GUIDANCE, WHICH IS A GOOD TREND
CONSIDERING THE GRADUAL SLOWING SEEN IN THE LAST SEVERAL RUNS. FOR
THE LATEST OFFICIAL GUIDANCE, SEE THE MOST RECENT ADVISORY FROM
THE NATIONAL HURRICANE CENTER.
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.
TAYLOR
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