Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1237 PM EDT Thu Nov 01 2018

Valid Nov 01/1200 UTC thru Nov 05/0000 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 the 12Z NAM/GFS and 00Z ECMWF
Confidence: Slightly Above Average

The models generally agree on the large scale with the details of
the longwave trough amplifying into the eastern U.S. over the next
36 hours before then then pivoting rapidly northeast in a
negatively tilted fashion across the Mid-Atlantic and Northeast.
The 00Z CMC though was a little slower than the remaining guidance
which is rather well clustered at aloft and also with the
associated surface low that will deepen from the Ohio Valley to
the Northeast.

A new upper trough and associated surface low will then drop
southeast down across the central Plains later Saturday and
Sunday, and then lift northeast up toward the upper Midwest and
upper Great Lakes region by Sunday night. The 12Z NAM ends up
being faster with the low track to the north across the Midwest,
with the 00Z CMC/UKMET solutions the slowest. The 12Z GFS and 00Z
ECMWF are clustered in between camps, but the latest GEFS mean and
ECENS mean are more progressive and lend support to the NAM, GFS
and ECMWF solutions. Elsewhere, a fast-moving shortwave will cross
the Pacific Northwest by late Sunday and Sunday night. The 00Z
CMC/UKMET solutions are a little more sheared/flatter with this
system compared to the 12Z NAM/GFS and 00Z ECMWF.

Based on the latest model clustering and ensemble spread, a blend
of the 12Z NAM/GFS and 00Z ECMWF will be preferred 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