Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
258 PM EDT Mon Sep 10 2018

Valid Sep 10/1200 UTC thru Sep 14/0000 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: Non 10/12Z NAM or 10/12Z CMC blend
Confidence: Above average

12Z Suite is in reasonable agreement with previous thinking. 12Z
CMC remains strong and then fast with shortwaves ejecting across
the Pacific NW in line with the NAM, which are not preferred in
the model blend. No other significant differences were noted with
the 12Z guidance.

General pattern features a ridge across the eastern United States
with a deepening trough across the eastern Pacific Ocean and into
the western CONUS. Model guidance in reasonable agreement across
the east with respect to mass fields through Thursday evening, but
differences exist in timing and intensity of shortwaves rotating
through the mean trough in the west. The upstream amplification of
a ridge into Alaska is of reasonable strength agreement among all
guidance, suggesting the NAM/CMC are too strong with the depth of
their shortwave energy being shedded into the Pacific NW as the
large scale trough re-amplifies. Otherwise no significant
differences are noted (except with Hurricane Florence, see below)
and a blend of the 10/12Z GFS, 10/00Z ECMWF, and 10/00Z UKMET is
suggested.


...Hurricane Florence...
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Preference:  See NHC forecast discussion
 Best Proxy:  06z GFS Parallel (FV3), 10/12Z ECMWF, and 10/12Z
UKMET blend

06Z GFS Parallel with the 10/12Z ECMWF and 10/12Z UKMET continue
to closely resemble the latest NHC track for Hurricane Florence. A
blend of these brings a track very close to the official from NHC.
Please refer to the latest NHC discussions and products for more
detailed information.

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

Weiss/Bann