Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
1256 AM EDT Wed Aug 29 2018

Valid Aug 29/0000 UTC thru Sep 01/1200 UTC

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

00Z NAM/GFS Model Evaluation with Preliminary Preference and
Confidence
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...Overall Synoptic Pattern across the CONUS...
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Preference: Non 00Z UKMET General Blend
Confidence: Slightly Above Average

A trough will eject from the Midwest to eastern Canada through
Thursday, with an associated cold front sagging into the Southeast
and stalling Friday. The next trough will enter the Pacific
Northwest today and drift east, maintaining a positive tilt as the
northern extent reaches the northern Great Plains Friday.

Models are in generally good agreement into Day 2 with the 12Z
UKMET farther north with the ridge over the central CONUS ahead of
the trough. Model differences then develop with the trough digging
into the West on Friday. The 00Z NCEP guidance remains flatter
with this wave compared to non-NCEP guidance. However, the impact
to precipitation placement downstream (over the upper Midwest) is
minimal. The only significant precipitation difference in Day 3
QPF among the guidance is the 12Z UKMET which is farther south
with the front in the east. Little change is noted in the Day 3
QPF with the 00Z GFS versus the 12Z.

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

Jackson