Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
255 PM EDT Wed Aug 29 2018

Valid Aug 29/1200 UTC thru Sep 02/0000 UTC

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

12Z model evaluation with final preference
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...Overall Synoptic Pattern across the CONUS...
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Preference: 12Z GFS / 12Z ECMWF blend
Confidence: Slightly above average

19Z update: Some changes were noted in the 12Z UKMET/CMC toward
the previous preference across the West with 500 mb heights which
helps the case for a GFS/ECMWF blend. Otherwise, changes made
across the remaining portions of the U.S. were minor in the 12Z
ECMWF/UKMET/CMC compared to their previous 00Z cycles.

The upper pattern will feature a series of progressive shortwaves
advancing through southern Canada and the northern tier of the
U.S. through Saturday, with an eventual evolution toward mean
troughing across the western U.S. while mid-level ridging
continues out East.

The biggest differences were noted across the western U.S. with
the 00Z CMC flatter with the degree of amplification through
Saturday compared to the remaining model consensus. The 00Z UKMET
was also noted to be a bit more amplified with energy advancing
through quasi-zonal flow into southwestern Canada Saturday morning
compared to the remaining consensus. Elsewhere, the NAM was noted
to be strongest with a disorganized low-level wave in the Gulf of
Mexico by Saturday morning.

A GFS/ECMWF blend is recommended given the best agreement to the
ensemble means and remaining deterministic guidance.

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

Otto/Weiss