Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
237 PM EDT Mon Jul 30 2018

Valid Jul 30/1200 UTC thru Aug 03/0000 UTC

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

12Z model evaluation and preferences
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...Overall Synoptic Pattern across the CONUS...
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Preference: Blend of 12Z GFS/UKMET
Confidence: Slightly Above Average

A mean trough remains to the east of the Rockies, sandwiched
between Four-Corners ridging and western Atlantic ridging. A
briefly closed low over the lower Missouri Valley will lift as the
next northern stream wave drops into the trough, and a separate
upstream shortwave trough becomes better defined over the Pac NW,
Northern Rockies over time. Overall the models are fairly well
clustered. If choosing one way to lean, it would be toward a blend
of the 12Z GFS and UKMET, supported by the consistent GEFS mean.
The depth and progression of the trough in the east, in
particular, favors the GEFS, as the ECMWF Ensemble Mean has been
trending toward the GEFS for several cycles. As spread increases
on Day 3, the least favorable solution appears to be the 12Z NAM
which is generally too fast with the pattern. The 12Z ECMWF looks
good in the eastern U.S., but becomes fast with the northern
Rockies system, especially at the surface.

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

Burke