Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
105 AM EDT Fri Sep 14 2018

Valid Sep 14/0000 UTC thru Sep 17/1200 UTC

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

00Z NAM/GFS evaluation including preliminary preferences and
confidence
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...Overall synoptic pattern across the CONUS...
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Preference: 00Z GFS, 00Z NAM, 12Z ECMWF blend
Confidence: Average

A longwave trough along the west coast will remain in place into
Monday morning as a couple of shortwaves move through. One
shortwave is forecast to move across central CA on Saturday and
the base of a larger shortwave/closed low should cross into the
Pacific Northwest on Sunday. The former shortwave should spin up a
surface low along a front in the north-central U.S. on Sunday with
the 12Z UKMET noted as the slowest of the models, with the 12Z CMC
a bit weaker with the 850 mb low as the system tracks into
southern Canada late Sunday. A 00Z GFS/NAM and 12Z ECMWF blend
appears the best fit for the western to north-central U.S.


...Western Gulf coast trough/low nearing south Texas this
morning...
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Preference: General model blend
Confidence: Average

There are minor differences in the guidance concerning evolution
of a disturbance in the western Gulf of Mexico, approaching Texas.
NHC has a 50 percent chance of development over the next 48 hours
as it lifts NW towards the Texas coast. The models show some minor
timing differences with the 12Z UKMET perhaps strongest of the
deterministic guidance. A general model blend is preferred here,
perhaps led by the 00Z GFS and 12Z ECMWF.

Please continue to refer to the latest NHC discussions and
products for more detailed information on this system.


...Hurricane Florence...
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Preference:  00Z NAM/00Z GFS/12Z UKMET closet to 03Z NHC advisory

Most models are in good agreement until shortly after landfall
Friday with no single model agreeing through the entire short
range period on the track of Florence. A combination of the 00Z
NAM (south of the NHC track) and 00Z GFS (north of the NHC track)
along with the 12Z UKMET (slower and south of NHC) is preferred.

Please refer to the latest NHC discussions and products for more
detailed information on Hurricane Florence.

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

Otto