Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1138 AM 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 NAM/GFS Model Evaluation...with Preliminary Preferences and
Confidence
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...Overall Pattern Across the CONUS...
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Preference: Non 00Z UKMET/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.

A broader trough in the 00Z UKMET/CMC shifts the surface trough
farther off the East Coast/farther south over FL by Monday.
Therefore, precipitation along this trough is shunted farther
south than the rest of the guidance which is in good agreement.
The 00Z UKMET/CMC are 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