Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
346 PM EDT Sat Sep 15 2018

Valid Sep 15/1200 UTC thru Sep 19/0000 UTC

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

12Z model evaluation with final preferences and confidence
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...Overall preference for the lower 48...
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Preference: Non-GFS blend across southeastern Canada/northeastern
U.S. Mon-Tue
Confidence: Average

The GFS remains a relative outlier with respect to the mid level
shortwave and its associated surface low/front moving across
southeastern Canada Tue-Wed.  Although it is less amplified than
its 00z run, it is still one of the more amplified deterministic
solutions.

Elsewhere across the CONUS (outside of Florence described below),
the models show relatively minor differences -- which may be
largely addressed by a model compromise.

...Tropical Storm Florence...
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Preference: UKMET blend closest to 15Z NHC advisory

Spread amongst the deterministic guidance for Florence becomes
notable by late Mon into early Tue, with the NAM becoming one of
the more significant outliers as it lifts the system more quickly
to the northeast out of the Ohio valley into the lower Great Lakes
region. Overall, the 12Z UKMET was generally closest to the 15Z
NHC track.

Please see NHC advisories/discussions for the latest forecast
track and thoughts concerning Florence.

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

Pereira