Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1209 PM EDT Fri Mar 15 2019
Valid Mar 15/1200 UTC thru Mar 19/0000 UTC
...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...
12Z Model Evaluation Including Preferences and Confidence
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...Shortwave energy over the northern Plains/Midwest...
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Preference: Blend of the 12Z GFS and 00Z ECMWF
Confidence: Average
In the wake of the exiting deep cyclone over the Midwest and Great
Lakes will be an intrusion of northern stream shortwaves from
southern Canada which will cross the northern Plains and Midwest
through the weekend. The 12Z NAM is a bit sharper with the
shortwave impulses and is overall a bit more out of phase with the
global models. The 00Z UKMET/CMC solutions also show some evidence
of being at least a bit too sharp with energy late in the period
dropping down across southern Canada and toward the Upper Midwest.
The best model clustering and ensemble support favors the 12Z GFS
and 00Z ECMWF, and thus a blend of these solutions will be
preferred.
...Weak upper trough/closed low moving into the Southwest...
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Preference: Blend of the 12Z NAM and 00Z ECMWF
Confidence: Slightly above average
A weak upper trough and associated closed low will move into the
Southwest through the weekend and should begin to dampen out and
shear east toward the southern High Plains by Monday. The 00Z
UKMET/CMC solutions are a bit more progressive late in the period
in taking the energy across the southern High Plains. The 12Z NAM
and 00Z ECMWF are a bit slower and cluster well with the
GEFS/ECENS member suites. The 12Z GFS appears to be a bit of a
weaker outlier compared to the remaining guidance. So, for now
will lean toward a blend of the 12Z NAM and 00Z ECMWF at this time.
...Shortwave over the northern Rockies by Sun...
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Preference: Blend of the 12Z GFS and 00Z CMC/ECMWF
Confidence: Slightly above average
The 12Z NAM and 00Z UKMET are relatively stronger outliers with
the shortwave rounding the mean layer ridge along the West Coast
on Sunday and dropping down over the northern Rockies. The
remaining guidance as per the 12Z GFS, 00Z CMC and 00Z ECMWF is a
tad weaker and tends to have better ensemble support, and thus the
preference will be toward the weaker consensus.
Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml
Orrison