Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
235 AM EDT Sun Mar 15 2020
Valid Mar 15/0000 UTC thru Mar 18/1200 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
00Z Model Evaluation with Latest Preferences and Confidence
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...Deep upper trough/closed low impacting the West Coast...
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Preference: General model blend
Confidence: Above average
A deep upper trough and embedded closed low along the West Coast
will gradually settle south over the next few days, and should
begin to pivot somewhat off to the east by the middle of the week
which will allow for more of an impact on the Great Basin and also
the Southwest. The guidance is in good overall agreement with
their mass fields, but with the 00Z GFS just a tad faster and
farther east with the trough progression at the end of the period
compared to the non-NCEP guidance. The model spread is still quite
modest, and so a general model blend will be preferred with this
system through the middle of the week.
...Trough crossing the Upper Midwest/Great Lakes by Tuesday...
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Preference: General model blend...through 48 hours
Blend of the 00Z GFS/CMC/ECMWF...after 48 hours
Confidence: Average
A northern stream trough will cross the northern Plains, Upper
Midwest and Great Lakes region by Tuesday, with an accompanying
cold front sweep from the Midwest into the eastern U.S. This front
will then sweep off the East Coast by Wednesday as the upper
trough quickly exits the Great Lakes and crosses the Northeast.
After about 48 hours, the 00Z NAM becomes a bit slower than the
global models which have now all generally come into agreement on
a more progressive solution. The 00Z UKMET though appears to be a
bit too progressive by the end of the period. Based on the latest
model trends and clustering, a blend of the GFS, CMC and ECMWF
will be preferred after about 48 hours, with a general model blend
sufficing prior to this.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Orrison