Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1130 PM EST Fri Nov 16 2018

Valid Nov 17/0000 UTC thru Nov 20/1200 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: 00z GFS, NAM / 12z ECMWF blend
Confidence: Average

Quasi-zonal flow exists across the northern tier of the US to
start the short range forecast period with a couple embedded
shortwaves noted across the Upper Mississippi Valley and north
central Montana. As this features advance downstream, a weak
positively titled trough will take shape, enhancing the troughing
over the central US into early next week. Across the western US,
the offshore ridge will slowly push inland and begin to break down
as a shortwave approaches the Pacific NW and an upper level low
slides toward southern California. At the surface, the absence of
major storm systems will bring relatively benign weather to much
of the CONUS. The exception will be a weak wave passing through
the Ohio Valley and lower Great Lakes Monday - Monday night and
also a stalled/lingering frontal boundary along the southern Texas
Gulf Coast which could bring periods of heavy rainfall.

In general, the guidance shows good agreement with the major
synoptic features. The UKMET is likely too fast with the shortwave
trough over the Great Lakes and New England by Tuesday, while the
CMC is strongest of the deterministic models. The NAM/GFS/ECMWF
show fairly good agreement. The bigger differences lie in the
smaller scale details, especially across the southern Texas Gulf
Coast with respect to QPF and where the axis of heaviest rainfall
falls. The NAM is faster to push the coastal low offshore (less
rainfall), while the GFS/ECMWF are similar with more QPF along the
immediate coast.

So overall, a blend of the 00z GFS/NAM with the 12z ECMWF is
preferred 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