392
FXUS10 KWNH 040642
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
242 AM EDT SAT JUL 04 2020
VALID JUL 04/0000 UTC THRU JUL 07/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
6Z UPDATE: THE ECMWF TRENDED A LITTLE STRONGER WITH THE TROUGH
BUILDING IN ACROSS NEW ENGLAND BY THE END OF THE WEEKEND, WHEREAS
THE UKMET AND CMC ARE NOW SLIGHTLY WEAKER WITH IT. OUT WEST, THE
UKMET IS NOT AS TROUGH WITH THE TROUGH ON DAY 3 COMPARED TO ITS
12Z RUN. OVERALL, NO CHANGES APPEAR NECESSARY IN TERMS OF OVERALL
MODEL PREFERENCES.
TROUGH BUILDING OVER THE NORTHEAST U.S. THIS WEEKEND
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
A PAIR OF SHORTWAVE TROUGHS ARE EXPECTED TO MOVE THROUGH THE
NORTHEAST OVER THE NEXT FEW DAYS, WITH THE FIRST ARRIVING BY
SATURDAY MORNING. A GENERAL MODEL BLEND FOR MASS FIELD PURPOSES
IS SUFFICIENT HERE. A SECOND SHORTWAVE TROUGH THEN ARRIVES BY
LATE SUNDAY, AND IS EXPECTED TO CLIP THE NORTHERN AREAS OF THE
NORTHEAST AND ACROSS NEW ENGLAND. THE CMC, GFS, AND UKMET ARE
MORE AMPLIFIED WITH THIS TROUGH AS IT CROSSES THE REGION AND THEN
OFFSHORE, WITH THE UKMET INDICATING THE SLOWEST SOLUTION.
TROUGH OVER THE GULF COAST REGION
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF BLEND
CONFIDENCE: MODERATE
A SLIGHT WEAKNESS IN THE UPPER LEVEL RIDGE ANCHORED OVER THE
CENTRAL/SOUTHERN PLAINS EXPANDS FURTHER DURING THE COURSE OF THE
PERIOD AS SEVERAL CONVECTIVELY ENHANCED MCVS SETTLE OVER THE LOWER
MS RIVER VALLEY AND GULF COAST REGION (WHILE THE RIDGE UPSTREAM
RETREATS TO THE SOUTHWEST U.S.). THE SYNOPTIC PATTERN IS LARGELY
AGREEABLE THOUGH THE UKMET IS A LITTLE STRONGER WITH THE UPPER
RIDGE COMPARED TO THE OTHER GUIDANCE. THE ECMWF AND GFS ARE CLOSE
ENOUGH TO THEIR RESPECTIVE MEANS TO MERIT A BLEND OF THOSE TWO
MODELS.
PAIR OF TROUGHS AFFECTING THE NORTHWESTERN U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GFS/ECMWF BLEND
CONFIDENCE: MODERATE
THE FLOW PATTERN ACROSS THE NORTHWESTERN QUADRANT OF THE NATION IS
EXPECTED TO REMAIN ACTIVE AS A LARGE SCALE TROUGH REMAINS IN PLACE
ACROSS THE REGION. THE FIRST SHORTWAVE TRACKING ACROSS THE
PACIFIC NORTHWEST ON SATURDAY IS EXPECTED TO REACH MANITOBA BY
MONDAY MORNING, AND THIS WILL SUPPORT A COLD FRONT CROSSING THE
NORTHERN HIGH PLAINS. THE MODELS ARE IN DECENT AGREEMENT WITH
THIS FIRST SYSTEM. A SECOND SHORTWAVE REACHES THE PACIFIC
NORTHWEST BY MONDAY AFTERNOON AS THE OVERALL PATTERN AMPLIFIES
SOME. THE GFS IS SLIGHTLY FASTER AND THE CMC IS A BIT SLOWER, AND
A STRONGER SOLUTION WITH THE UKMET BY TUESDAY MORNING. AS A
COMPROMISE AND CONSENSUS, A BLEND OF THE GFS/NAM/ECMWF 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
HAMRICK
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