813
FXUS10 KWNH 121903
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
303 PM EDT SUN JUL 12 2020
VALID JUL 12/1200 UTC THRU JUL 16/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH FINAL PREFERENCES/CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-LEVEL SHORTWAVE TROUGHING OVER THE NORTHEASTERN QUARTER OF
THE U.S. MONDAY TO WEDNESDAY...
PREFERENCE: BLEND OF 12Z NAM AND 12Z ECMWF
CONFIDENCE: AVERAGE
A MID-UPPER LEVEL TROUGH CROSSES NY/NEW ENGLAND TONIGHT AND
MONDAY, EVENTUALLY MOVING OFF THE NEW ENGLAND COAST ON TUESDAY.
WEAK WAVES OF LOW PRESSURE ARE EXPECTED TO DEVELOP ALONG THE FRONT
FROM THE NORTHERN MID ATLANTIC TO EASTERN NEW ENGLAND.
SLIGHT TIMING DIFFERENCES PERSIST AS THE MID-LEVEL CLOSED LOW
MOVES FROM EASTERN NEW ENGLAND INTO THE COASTAL WATERS. THE 12Z
ECMWF MOVED THE 700 MB LOW FASTER, SO THE 12Z ECMWF/12Z CMC/12Z
NAM ARE IN THE MIDDLE, WITH THE 12Z GFS FASTER TO MOVE THE LOW
OFFSHORE. THE 12Z UKMET ALSO MOVED THE 700 MB LOW OFF FASTER, SO
THE TREND IN THE NEW 12Z ECMWF LOOKS GOOD.
...LONGWAVE TROUGH AXIS MOVING THROUGH THE NORTH-CENTRAL U.S.
THROUGH WEDNESDAY ..
PREFERENCE: BLEND OF 12Z CMC/12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE MODELS SHOW GOOD OVERALL AGREEMENT WITH A BROAD 500 MB TROUGH
AND ASSOCIATED SURFACE COLD FRONT MOVING ACROSS THE NORTHERN
ROCKIES AND NORTHERN PLAINS TONIGHT AND MONDAY, THEN OUT OF THE
NORTHERN PLAINS TO THE UPPER MS VALLEY TUESDAY. SOME MINOR TIMING
AND AMPLITUDE DIFFERENCES WERE SEEN, WITH THE 12Z GFS A BIT FASTER
AND 12Z NAM SLIGHTLY MORE AMPLIFIED TUE. THE 00Z-12Z CANADIAN
GLOBAL AND ECMWF REPRESENT THE MIDDLE GROUND, BUT THE DIFFERENCES
AMONG THE ARE SMALL ENOUGH TO SUPPORT A GENERAL MODEL BLEND FOR
THE PREFERENCE.
THE 12Z GFS APPEARS TO LOWER 700 MB HEIGHTS/SEA LEVEL PRESSURE
NEAR WHERE IT PRODUCES CONVECTION IN SOUTHERN WI/NORTHERN IL. THE
GFS MIGHT BE SUFFERING FROM A BIT OF CONVECTIVE/GRID SCALE
FEEDBACK, SO THE LOW PRESSURE FURTHER SOUTH DEPICTED IN THE 12Z
CANADIAN GLOBAL/09Z SREF MEAN/12Z ECMWF/12Z NAM/00Z ECMWF ENSEMBLE
MEAN IS 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.
PETERSEN
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