Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
153 AM EST Sun Dec 16 2018

Valid Dec 16/0000 UTC thru Dec 19/1200 UTC

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

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

...Overall Pattern Across the CONUS...
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Preference: Multi Model Blend
Confidence: Above Average

07z Update: A multi model blend still looks good across the CONUS
through day 3. The 0z CMC did indeed slow a tad with the central
U.S. trough on day 3 to come into line with the better model
cluster. Some differences remain with the details of the northeast
low, but from a synoptic standpoint agreement is good.

Original Discussion...

Overall model agreement across the CONUS remains above average
over the next three days. Still some minor run to run fluctuations
with the northeastern U.S. low, but in general all model solutions
appear reasonable and within the expected spread for the lead
time.

Across the west, clustering is good with the progressive trough
moving across Monday, and with the tight zonal flow and
atmospheric river moving into the Pacific Northwest later Monday
into Tuesday.

The largest model spread, although still not large, appears to
exist with the developing troughing over the central U.S on
Tuesday. There are some depth and timing differences with this
feature, although for a day 3 forecast the spread is not all that
large. The 12z CMC may be a tad to quick with this trough, and the
0z NAM may be a bit too deep, but neither really appears to be an
egregious outlier. Thus a multi model blend should be fine here as
well.


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

Chenard