Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1236 AM EDT Mon Oct 29 2018

Valid Oct 29/0000 UTC thru Nov 01/1200 UTC

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

00Z Model Evaluation...with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Non-CMC model blend
Confidence: Slightly above average

The model preference maintains continuity with the previous
assessment after the 12Z model cycle. The preference is for a
non-CMC model blend, as the CMC shows: (1) more rapid height rises
behind the departing East Coast trough on Monday-Tuesday; (2)
considerably stronger southern stream vort max and sharper trough
digging into the Southern Plains on Wednesday. There is limited
model support for these ideas, and therefore the 12Z CMC is not
included in the preference.

Otherwise, model agreement with the mass fields is relatively
good, and QPFs are reasonably similar. A blend of available
deterministic models is therefore preferred, to account for some
of the detail differences despite the overall agreement. The
biggest differences exist in the Pacific Northwest, where the 00Z
GFS and NAM are further south and weaker with their placement of
the QPF, while the 12Z ECMWF and UKMET are further north. This
appears to be related to the amplitude of the ridge. In this
region, WPC QPF was weighted more toward the wetter and northward
scenario offered by the ECMWF and UKMET, as the 18Z GEFS mean was
more amplified with the ridge than the deterministic GFS, and
significant ridge amplification is anticipated given the strength
of the downstream trough.


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

Lamers