Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
212 PM EST Sun Dec 02 2018

Valid Dec 02/1200 UTC thru Dec 06/0000 UTC

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

12Z Model Evaluation...with Preferences and Confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Slightly above average

---19z update---
No significant changes noted with the rest of the 12z guidance, so
the general model blend is still preferred.


---previous discussion---
Through the early part of the forecast period, the latest model
guidance shows very good agreement and little spread with the
synoptic pattern across the CONUS. The departing shortwave and
storm system across the Midwest and Great Lakes will lift
northeastward with general troughing expected across the CONUS
through Monday. An approaching trough for the western US has
little variability in the model mass fields with perhaps some
timing differences that are relatively minor.

Some differences are noted toward the end of the forecast period
(Tuesday night into Wednesday) with respect to a couple of digging
shortwaves across the northern US into the mid-Atlantic region.
The NAM/CMC are stronger and dig deeper compared to the GFS/ECMWF,
and also the ECMWF is a bit further south compared to the rest of
the guidance.

Across the FL panhandle and southeast Georgia, the NAM lingers the
frontal boundary across the area the longest (and further north)
and also produces an axis of heavy rainfall into Monday Night,
while the rest of the deterministic models are faster to kick the
moisture off the coast. The ECMWF is closet to the NAM solution,
though is not nearly as wet with the heavy rainfall. While the NAM
is a bit of an outlier, it has performed slightly better with this
event, so some support toward its slower solution is given.

As a result, a general model blend should suffice across the CONUS
at this time.


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

Taylor