179
FXUS10 KWNH 040457
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1256 AM EDT TUE AUG 04 2020
VALID AUG 04/0000 UTC THRU AUG 07/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..HURRICANE ISAIAS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 03Z NHC ADVISORY PACKAGE
BEST MODEL PROXY: MULTI-MODEL CONSENSUS
HURRICANE ISAIAS MADE A LANDFALL AT 0310Z NEAR OCEAN ISLE BEACH,
NC. THE STORM IS CONTINUING TO ACCELERATE OFF TO THE
NORTH-NORTHEAST AND WILL BE ADVANCING UP ACROSS THE MID-ATLANTIC
COASTAL PLAIN THROUGH MIDDAY TUESDAY, AND THEN CROSSING NEW
ENGLAND LATE TUESDAY THROUGH TUESDAY NIGHT. THE 00Z NAM AND 00Z
GFS SOLUTIONS HAVE COME IN JUST A TAD LEFT OF THE 03Z NHC TRACK,
AND AFTER ABOUT 12 HOURS ARE JUST A TAD FASTER AS WELL. THE 12Z
NON-NCEP SOLUTIONS ARE ALL A TAD SLOWER AND LOCALLY A TAD TO THE
RIGHT OF THE NHC TRACK. HOWEVER, THE 00Z HRRR AND 00Z HREF MEMBER
SUITE ARE ALL A TAD LEFT OF THE NHC TRACK, AND ESPECIALLY AFTER
ABOUT 12 HOURS AS THE SYSTEM CROSSES THE NORTHERN MID-ATLANTIC AND
MOVES INTO THE NORTHEAST. PLEASE CONSULT THE LATEST NHC FORECAST
ADVISORY PACKAGE FOR MORE DETAILS.
..BROAD TROUGH FROM THE GREAT LAKES TO THE GULF COAST
..CLOSED LOW OVER ONTARIO
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
A BROAD TROUGH EXTENDING FROM THE GREAT LAKES DOWN TO THE CENTRAL
GULF COAST WILL BE KEY IN ALLOWING HURRICANE ISAIAS TO LIFT
RAPIDLY NORTH-NORTHEAST UP ALONG THE EASTERN SEABOARD OVER THE
NEXT 24 TO 36 HOURS. THE MODELS ARE IN GOOD AGREEMENT IN
MAINTAINING THE BROAD TROUGH THROUGH THE PERIOD, BUT WITH SOME
STRONGER NORTHERN STREAM ENERGY OVER THE GREAT LAKES REGION
FAVORING A CLOSED LOW EVOLUTION UP OVER ONTARIO. THE MODELS ARE IN
GOOD SYNOPTIC SCALE AGREEMENT WITH THEIR MASS FIELD EVOLUTION, SO
A GENERAL MODEL BLEND WILL BE PREFERRED.
..UPPER TROUGH CROSSING THE PACIFIC NORTHWEST
...ENERGY DROPPING DOWN OVER THE NORTHERN PLAINS/MIDWEST FOR
TUESDAY/WEDNESDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z NAM/GFS AND 12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
AN UPPER TROUGH WILL CROSS FAR SOUTHWEST CANADA BEFORE THEN
DROPPING SOUTHEAST AND DIGGING ACROSS THE NORTHERN PLAINS AND
MIDWEST TUESDAY AND WEDNESDAY. THE 12Z UKMET GRADUALLY BECOMES A
TAD WEAKER WITH THE ENERGY AS IT DIGS ACROSS THE MIDWEST, AND THE
12Z CMC ENDS UP A BIT STRONGER AND SLOWER. THE 00Z NAM/GFS AND 12Z
ECMWF ARE PRETTY WELL CLUSTERED THROUGH THE PERIOD AS THE ENERGY
ADVANCES INTO THE GREAT LAKES REGION AND REINFORCES A BROAD TROUGH
OVER THE REGION. A BLEND OF THESE MODELS WILL BE PREFERRED AS A
RESULT.
..SOUTHERN STREAM TROUGH MOVING INTO CA BY WEDNESDAY
..POSSIBLE CLOSED LOW OVER CA BY FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE MODELS ARE IN VERY GOOD AGREEMENT WITH THE INITIAL TROUGH
COMING IN ACROSS CA ON WEDNESDAY, AND ALSO WITH REINFORCING
SHORTWAVE ENERGY AND POSSIBLE CLOSED LOW DEVELOPMENT OVER NORTHERN
CA BY FRIDAY. A GENERAL MODEL BLEND WILL BE PREFERRED FOR THE TIME
BEING.
..UPPER TROUGH APPROACHING THE PACIFIC NORTHWEST WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: ABOVE AVERAGE
A RELATIVELY DEEP TROUGH WILL BE APPROACHING THE PACIFIC NORTHWEST
BY LATE WEDNESDAY AND THE MODELS ARE OVERALL IN VERY GOOD
AGREEMENT WITH THEIR TIMING AND DEPTH. HOWEVER, THE 00Z NAM IS A
TAD ON THE STRONG SIDE WITH ITS HEIGHT FALLS COMPARED TO THE
WELL-CLUSTERED GLOBAL MODELS. THEREFORE, A NON-NAM BLEND WILL BE
PREFERRED WITH THIS NEXT TROUGH.
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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