Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1105 AM EST Mon Nov 19 2018

Valid Nov 19/1200 UTC thru Nov 23/0000 UTC

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

12Z Model Evaluation...with Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: Blend of 12Z NAM/GFS and 00Z ECMWF
Confidence: Slightly above average

Through the forecast period, quasi-zonal split flow will become
more amplified with a Western U.S. ridge advancing east and
downstream troughing over the Eastern U.S. Meanwhile, a closed low
off the southern California coast will open up and then track
progressively across the southern tier of the CONUS. Elsewhere, a
series of weak surface lows and associated shortwaves will track
across the northern tier of the U.S.

Fairly good agreement in the model guidance is seen with the low
pressure center that impacts New England Tuesday and Tuesday
night, and also with the secondary clipper-type shortwave and low
center that impacts the Great Lakes and the Northeast through
Wednesday. 

The models show only minor mass field spread with the ejecting
southern stream energy, and by the end of the period, the guidance
shows rather good agreement with the shortwave energy traversing
the Great Basin and Four Corners region. Elsewhere, the guidance
also shows good agreement with the vigorous shortwave and upstream
Pacific jet taking aim in the Pacific Northwest which will bring
the leading edge of an atmospheric river into the coastal ranges.

Based on the latest mass field clustering and trends, the
preference will be for a blend of the 12Z NAM/GFS and 00Z ECMWF
across the CONUS.


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

Orrison