Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1146 AM EST Fri Nov 16 2018

Valid Nov 16/1200 UTC thru Nov 20/0000 UTC

...See NOUS42 KWNO (ADMNFD) for the status of the upper air
ingest...

12Z NAM/GFS Evaluation...with Preliminary Preferences and
Confidence
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...Overall Pattern Across the CONUS...
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Preference: non 12Z NAM blend
Confidence: Average

The synoptic scale pattern shows broad upper level troughing in
place over the northern tier of the U.S. to start the short range
forecast with a pair of shortwaves exiting the Northeast today
while a pair of shortwaves in the West (British Columbia and
Montana) advance downstream. Through Monday, troughing over the
East will amplify and translate eastward while ridging currently
just offshore of the West Coast translates to the Great Basin for
Monday afternoon.

Surface/low-level waves are not very defined over the lower 48
through early next week once a strong coastal low departs from the
Northeast tonight. Model agreement is generally good through
Tuesday but the 12Z NAM is slightly slower/deeper with a northern
stream shortwave/surface low across the upper Mississippi Valley
on Monday and a bit farther north with a weak surface wave near
Texas on Monday into Tuesday. While the 12Z NAM is not a complete
outlier with respect to the ensembles, it is a deterministic
outlier and lacks enough support to include is as part of the
preference at this time.

Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml
500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml

Otto