281
FXUS10 KWNH 071708
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
107 PM EDT TUE JUL 07 2020
VALID JUL 07/1200 UTC THRU JUL 11/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z INITIAL MODEL EVALUATION WITH MODEL PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW MOVING EAST ACROSS SOUTH-CENTRAL CANADA THROUGH FRIDAY
ASSOCIATED COLD FRONT CROSSING THE NORTHERN PLAINS
WEDNESDAY/THURSDAY AND THE GREAT LAKES FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM/GFS
CONFIDENCE: AVERAGE
A SLIGHTLY NEGATIVELY TILTED TROUGH AXIS OVER THE PACIFIC
NORTHWEST THIS MORNING SWINGS NORTHEAST OVER THE NORTHERN ROCKIES
TODAY, CLOSING OVER ALBERTA TONIGHT. THIS LOW THEN SHIFTS EAST
ACROSS THE CANADIAN PRAIRIES THROUGH THURSDAY BEFORE OPENING AND
LIFTING NORTHEAST OVER NORTHERN ONTARIO ON FRIDAY. THE ASSOCIATED
COLD FRONT SHIFTS ONTO THE MONTANA PLAINS THIS EVENING AND CROSSES
THE DAKOTAS THROUGH WEDNESDAY NIGHT BEFORE CROSSING THE CENTRAL
GREAT LAKES THROUGH FRIDAY. THE 12Z GFS/NAM BECOME MORE
PROGRESSIVE WITH THE LEADING TROUGH/COLD FRONT OVER THE NORTHERN
PLAINS WEDNESDAY NIGHT WITH THE GFS SLIGHTLY OUTPACING THE NAM FOR
TROUGH PROGRESSION THROUGH THE GREAT LAKES FRIDAY. GIVEN THE
PROPENSITY FOR THE GFS TO BE TOO FAST, A COMPROMISE WITH THE NAM
IS REASONABLE FOR NOW. EXPECT 12Z NON-NAM GUIDANCE TO BECOME MORE
PROGRESSIVE WITH THEIR 12Z RUNS WITH THIS FEATURE.
NEXT TROUGH MOVING INTO THE PACIFIC NORTHWEST THURSDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC GENERAL MODEL BLEND
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE GUIDANCE SHOWS GENERAL AGREEMENT WITH THE DEPTH AND
PROGRESSION OF THIS FEATURE INTO THE PACIFIC NORTHWEST LATE
THURSDAY WITH THE 00Z CMC NOTABLY MORE POSITIVELY TILTED AND
SLOWER THAN THE REST OF THE GUIDANCE MAKING IT AN OUTLIER.
LOW PRESSURE MOVING NORTHEAST ALONG EASTERN SEABOARD INTO THIS
WEEKEND
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z NAM/00Z ECMWF/CMC
CONFIDENCE: AVERAGE
A FAIRLY WEAK CYCLONE IS EXPECTED TO MOVE DRIFT EAST-NORTHEAST
ACROSS THE CAROLINAS THROUGH WEDNESDAY BEFORE TURNING NORTHEAST UP
THE EASTERN SEABOARD THURSDAY/FRIDAY AS A MID-LEVEL RIDGE BUILDS
TO THE NORTH ACROSS THE NORTHERN APPALACHIANS AND NEW ENGLAND. THE
PRESENCE OF THIS RIDGE CONTINUES TO SUGGEST A SLOWER SOLUTION. THE
12Z GFS REMAINS THE MOST PROGRESSIVE GUIDANCE WITH THE TURN NORTH
ON THURSDAY. THE 00Z UKMET IS BY FAR THE DEEPEST SOLUTION WITH A
WELL DEFINED CYCLONE DEVELOPING OFF NC ON THURSDAY BEFORE SHIFTING
NORTH. THE 12Z NAM AND 00Z ECMWF/CMC HAVE SIMILAR DEPTH AND TIMING
AND ARE PREFERRED AT THIS TIME.
SHORTWAVE TROUGH MOVING ACROSS NEW ENGLAND WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
GOOD AGREEMENT WITH THIS DAY 1 SHORTWAVE TROUGH CROSSING NORTHERN
NEW ENGLAND WEDNESDAY.
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 WITH THE 21Z ISSUANCE:
WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERMINATION.PDF
JACKSON
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