Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
240 PM EDT Mon Aug 06 2018

Valid Aug 06/1200 UTC thru Aug 10/0000 UTC

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

12Z Model Evaluation Including Preferences and Forecast Confidence
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...Overall Synoptic Pattern across the CONUS...
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Preference: blend of 00z/12z ECMWF, UKMET, and 06z GFS parallel
(Non-NAM blend)
Confidence: Slightly above average

The models agree that the deep layer trough moves slowly across
the Great Lakes and northeast the next couple of days. The 12z NAM
is a bit faster and more amplified than the other models at
700-500 mb with a stronger sfc wave developing just off the New
England coast Thu as a result. The 06z GFS parallel was slower
than the operational 12z run with the progression of the 700 mb
wave across the northeast and closer to the timing of the 00-12z
ECMWF and UKMET.

The 12z ECMWF/UKMET continue showing potential for embedded higher
amplitude 700 mb wave, but at different places in the Great
Lakes/Ohio Valley, so confidence is not high in any one solution,
thus the recommendation to blend the last couple of runs of the
ECMWF/UKMET/GFS parallel.

The 12z Canadian has backed off from its 00z run amplified wave
across the Great Lakes on Tue night-early Wed., and is now closer
to the UKMET solution and the amplitude of the forecast wave.
The 12z Canadian now shows a slightly more open wave at 700 mb in
AR on Thu, closer to the other solutions maintaining an open wave.


Confidence is slightly above average in the forecast period, given
the higher amplitude, slowly moving  ridge out across the Great
Basin/northern Rockies and the ridge drifting from the southeast
to Florida.

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

Petersen