Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
309 AM EDT Sat Sep 15 2018

Valid Sep 15/0000 UTC thru Sep 18/1200 UTC

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

00Z model evaluation with final preferences and confidence
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...Overall preference for the lower 48...
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Preference: 00Z ECMWF/UKMET blend
Confidence: Average

Southwest mid-level flow will be in place from the West Coast to
the upper Great Lakes region of the lower 48 through Tuesday
morning. A series of shortwaves will move through the westerlies
with a main surface low forming along a frontal boundary in place
across the north-central U.S. Saturday night into Sunday. The 00Z
GFS is a bit stronger with this shortwave and related surface low
into Ontario/Quebec. The result is the GFS being faster with the
cold front nearing Lakes Ontario and Erie Tuesday morning.

Elsewhere across the CONUS (outside of Florence described below),
there are only minor differences noted but the preference was
toward a 00Z ECMWF/UKMET blend given their better agreement to the
NHC track for Florence.


...Tropical Storm Florence...
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Preference: 00Z ECMWF/UKMET blend closest to 03Z NHC advisory

Differences between the deterministic guidance and the 03Z NHC
track for Florence begin to appear on Sunday with the 00Z ECMWF
and 00Z UKMET closest to NHC. The 00Z ECMWF/UKMET are also a bit
more defined with the mid-level reflection of Florence which
agrees well with the latest GEFS/ECMWF means.

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

Otto