Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
240 PM EST Fri Nov 30 2018

Valid Nov 30/1200 UTC thru Dec 04/0000 UTC

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

12Z Model Evaluation...with Final Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: Non 12Z CMC Blend
Confidence: Slightly above average

Model agreement on the evolution of the occluded cyclone in the
Central US and subsequent broad trough across the entire southern
CONUS continues to improve. The 12Z GFS now has as deep a
mid-level low as the rest of the guidance and has slowed its
progression northeast and is included in the preference. Also, the
12Z NAM no longer lags as much with the ejecting low and is in
line with consensus enough to warrant inclusion in the preference.

The broader trough remained in the 12Z CMC which means the surface
trough is shifted farther off the East Coast/farther south over FL
by Monday. The 12Z UKMET is much more in line with the consensus.
Precipitation along this trough in the 12Z CMC is shunted farther
south than the rest of the guidance which is in good agreement.
Therefore the 12Z CMC is excluded from the preference.

Differences in the eastern Pacific ridge are noted by Sunday
night, though since it remains off shore and the downstream
troughs have continental air, there is little to no precipitation
expected over the Pac NW and therefore, little impact to the
forecast.


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

Jackson