Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1218 AM EDT Sun Oct 28 2018

Valid Oct 28/0000 UTC thru Oct 31/1200 UTC

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

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

Over the next few days, the pattern across the CONUS will shift
from a western ridge and eastern trough to the reverse, and the
deterministic models are generally in good agreement with their
mass fields. The most amount of model spread appears to be after
30/00Z (Monday evening) related to the amplitude of the trough.
Two primary waves will be embedded in the amplifying trough: a
northern stream wave associated with a surface low, and a southern
stream wave digging into the southern Rockies.

The 12Z CMC and UKMET have higher heights than the other
deterministic models through the entire trough, and are flatter
with the southern stream wave in particular. The UKMET was among
the flattest models when compared to the entire NAEFS+ECMWF
ensemble, while there were a fair number of members with more
amplitude than even the deeper ECMWF, GFS and NAM forecasts.
Therefore, the preference is not only among the models with
greater consistency, but also with the ECMWF, GFS and NAM to
account for the possibility the digging trough could be even more
amplified than advertised.

Otherwise, the model QPFs are fairly similar across the CONUS, and
minor detail differences can be accounted for in a general blend
more substantially weighted to the ECMWF and GFS.


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

Lamers