Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
209 AM EST Fri Nov 23 2018

Valid Nov 23/0000 UTC thru Nov 26/1200 UTC

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

00Z Model Evaluation...with Final Preferences and Confidence
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...Overall Pattern Across the CONUS...
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Preference: Blend of 00Z ECMWF/UKMET
Confidence: Slightly Below Average

Two distinct shortwaves will swing eastward, spawning areas of low
pressure to affect the Southeast to Northeast Saturday into Sunday
along with the Midwest to Great Lakes late Saturday through
Monday. Out West, as upper ridging attempts to rebuild over the
region on Saturday, a broad upper trough will begin to approach
the Pacific Northwest early Monday.

Overall, a 00Z ECMWF/UKMET blend is recommended from coast to
coast. Out East, the 00Z GFS stands out significantly from the 00Z
deterministic consensus near and off of the East Coast and has had
poor run to run continuity. While the ensemble scatter low plot
spread is large by Sunday morning, the run to run continuity of
the non-GFS guidance has been fair with only small adjustments
made.

For the Midwest into the Great Lakes, the ensemble height spread
is modest but there is less spread in the surface low plots from
Sunday into Monday. Notable differences begin to appear starting
around Sunday morning over the Plains with 00Z GFS/CMC beginning
to pull away from the better clustering of the ensembles. The 00Z
GFS is faster with a less robust 500 mb trough compared to the
remaining guidance and the 00Z CMC is the fastest to move the 500
mb trough toward the east. On the other hand, the 00Z NAM is
slower/deeper. The favored middle ground is a blend of the 00Z
ECMWF/UKMET.

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

Otto