Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
229 AM EDT Sat Sep 07 2019

Valid Sep 07/0000 UTC thru Sep 10/1200 UTC

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

00Z Model Evaluation with Preferences and Forecast Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend, less GFS after 12Z Monday
Confidence: Average

Models are comparable across the CONUS through much of the short
range. Slight timing/amplitude differences were noted as an upper
shortwave moves from the northern Rockies to the Northern Plains
today/tonight and into the Great Lakes by Sun. Models show good
agreement that a second, more significant shortwave should move
onshore along the West Coast later today, crossing the Great
Basin/Rockies on Sun. As a surface low develops ahead of this
feature across the Northern Plains on Mon, the GFS becomes faster
than the model consensus, the result of a faster and weaker upper
shortwave by that time relative to other guidance. Another
shortwave is forecast to reach the West Coast Mon morning, part of
the amplification of a broader upper-level trough. Models are
reasonably close in their solutions for this system with only
minor timing/amplitude differences noted. Given these
considerations, a general model blend is preferred, with less
emphasis on the GFS after 12Z Monday due to its differences across
the Northern Plains.


...Hurricane Dorian...
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Please refer to the official National Hurricane Center forecast
track. Models showed relatively good consensus with respect to the
track of Dorian through Sunday as the system quickly moves
northeast into the Canadian Maritimes. In general, a non-NAM blend
of deterministic models should represent the NHC forecast track
well.


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

Ryan