Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1239 AM EDT Sat Jun 20 2020
Valid Jun 20/0000 UTC thru Jun 23/1200 UTC
...See NOUS42 KWNO (ADMSDM) for the status of the upper air
ingest...
00Z Model Evaluation Including Preferences and Forecast Confidence
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Closed low developing over northern high plains and parade of
shortwaves across central Plains
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Preference: General model blend through day 2; non-NAM blend day 3
Confidence: Average
Deterministic guidance remains in good agreement with the closed
upper low over Saskatchewan through day 2, however struggles exist
with the individual shortwaves that move through the fast zonal
flow across the central/northern Plains late in day 2 and on day
3. The first shortwave lifting through the Upper Midwest Saturday
is in good agreement across the spectrum of the deterministic
guidance. A pair of convectively induced shortwaves is expected
late in the period, Sunday/Monday, where there is significant
timing and strength differences. The non-NCEP guidance
(ECMWF/UKMET/CMC) show a faster/progressive flow with shortwave
energy moving through the mid-MS River Valley by the end of the
forecast period on d3 while the NAM and to some degree the GFS
shows slower movement with the shortwave energy remaining west
over KS/NE at the same time. With the expected fast cyclonic flow
in place, the faster solutions seen in the non-NCEP guidance is
favored at this time. The GFS is also considered as it has trended
toward the non-NCEP guidance, leaving a non-NAM blend as the
preference this cycle.
Troughs approaching the Pacific Northwest through Sunday
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Preference: General model blend
Confidence: Slightly above average
Shortwave troughs will rotate through portions of the Pacific NW
and B.C. over the next several days. While depth and timing
differences exist across the deterministic guidance, most of these
differences are minor 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
Taylor