588
FXUS10 KWNH 210716
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
315 AM EDT SUN JUN 21 2020
VALID JUN 21/0000 UTC THRU JUN 24/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW OVER MANITOBA/ONTARIO AND ASSOCIATED PARADE OF
SHORTWAVES ACROSS THE GREAT PLAINS TO MIDWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND DAY 1/2; NON-NAM BLEND DAY 3
CONFIDENCE: SLIGHTLY BELOW AVERAGE
07Z UPDATE: NO SIGNIFICANT CHANGES NOTED WITH THE REST OF THE 00Z
GUIDANCE.
THROUGH THE NEXT 3 DAYS, THE LARGE CLOSED LOW CURRENTLY OVER
MANITOBA WILL BE THE MAIN WEATHER FEATURE OVER THE CONUS. SEVERAL
SHORTWAVE TROUGHS ARE EXPECTED TO ROUND THIS LOW, INTERACTING WITH
EXISTING FRONTS WHICH WILL BE THE FOCUS FOR CONVECTIVE COMPLEXES
OVER MUCH OF THE CENTRAL US. THE EVOLUTION OF THE LARGE CLOSED LOW
AS IT WOBBLES TOWARD THE NORTHERN GREAT LAKES IS WELL REPRESENTED
AND AGREED ON WITH THE LATEST MODEL GUIDANCE. THE EXCEPTION IS BY
DAY 3 THERE ARE SOME SPATIAL DIFFERENCES, WITH THE UKMET AND NAM
DRIFTING FURTHER SOUTHEAST WHILE THE GFS IS CENTERED BACK TO THE
NORTHWEST. SURFACE LOW PRESSURE WILL MOVE FROM THE CENTRAL PLAINS
TOWARD THE GREAT LAKES THROUGH EARLY NEXT WEEK, WITH AGAIN SOME
SPATIAL SPREAD SEEN IN THE LATEST GUIDANCE. THE NAM IS A SLOWER
SOLUTION, HOLDING BACK THE LOW TO THE SOUTH WHILE THE REST OF THE
GUIDANCE IS PROGRESSIVE, RESULTING IN NOTABLE QPF DIFFERENCES. FOR
THIS REASON, A NON-NAM BLEND IS PREFERRED FOR DAY 3 WHILE A
GENERAL MODEL BLEND SHOULD SUFFICE FOR LARGE SCALE MASS FIELD
PURPOSES FOR DAY 1/2.
TROUGHS APPROACHING THE PACIFIC NORTHWEST TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
A COUPLE OF SHORTWAVES WILL MOVE ONSHORE THE PACIFIC NORTHWEST
THROUGH TUESDAY, ROUNDING THE BASE OF A DEEP GULF OF ALASKA LOW.
SOME TIMING AND STRENGTH DIFFERENCES ARE SEEN IN THE LATEST
DETERMINISTIC GUIDANCE BUT THE EFFECT ON SENSIBLE WEATHER AND QPF
IS MINIMAL SUCH THAT A GENERAL MODEL BLEND SHOULD BE SUFFICIENT.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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