Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1226 AM EDT Sat Aug 04 2018

Valid Aug 04/0000 UTC thru Aug 07/1200 UTC

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

00Z Model Evaluation Including Preference and Forecast Confidence
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...Overall Synoptic Pattern across the CONUS...
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Preference: General model blend
    Exclusions: 00z NAM (Northern Plains/Great Lakes)
                12z CMC (Off ME/Nova Scotia)
Confidence: Slightly above average

Models show good continuing agreement with the large scale
features with strongest agreement with the placement/timing and
strength of the Pacific closed low and Southwestern ridge. 
Overall greater agreement in timing was noted with the slowing of
the 00z GFS and 00z NAM toward the slower 12z UKMET/CMC/ECMWF
blend...yet by Monday the CMC shifts the surface and low level
cyclone further east of Nova Scotia.  As such would favor
eliminating the CMC in this area in a general model blend.

Across the Great Plains, the shortwave lifting out of the Central
Plains and lifting north eventually phasing and deepening the
surface low in Ontario by Sun, the 00z NAM shows some start of
over amplification with this wave. As the mean northern stream
slides eastward, advancing the cold front across the northern tier
into the Great Lakes and extending back to SE CO... here the NAM
while showing some similarities, the over amplification slows the
southward progression and is too far NW of the other guidance. 
The 00z GFS slowed a bit with this run and while it still remains
a bit faster than the ECMWF...there is strong support to blend
overall here.  As such, a Non-NAM blend is suggested across the
Northern Plains/Great Lakes.

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

Gallina