Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
256 PM EDT Wed Sep 11 2019

Valid Sep 11/1200 UTC thru Sep 15/0000 UTC

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

12Z Final Model Evaluation with Preferences and Forecast Confidence
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...Overall Pattern Across the CONUS...
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Preference: General model blend
Confidence: Slightly above average

The latest global guidance is in very good agreement with their
mass field forecasts over the next few days. The minor slower
trend in the northern Plains low and associated cold frontal
progression is noted in all 12Z global guidance. Since the heights
and precipitation are acceptably similar among the 12Z global
guidance a general model blend is preferred. The flow pattern will
deamplify/become zonal over the CONUS into the weekend which slows
the progression of the cold front moving into the eastern states.

The greatest model variability remains with the progression of a
trough pushing west from the Bahamas  Friday and extending across
FL and into the Gulf of Mexico through Saturday/Day 3. All
guidance has slowed the westward progression of the wave with the
12Z run with the GFS and CMC farther west, the ECMWF and NAM
farther east and the UKMET deeper and farther north. Given the
trough nature of this feature a general model blend is recommended
here too.


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

Jackson