Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
315 AM EDT Thu Oct 11 2018

Valid Oct 11/0000 UTC thru Oct 14/1200 UTC

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

00Z Final Model Evaluation...with latest preferences and confidence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

...Overall Pattern Across the CONUS... 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: Blend of the 11/00Z ECMWF/UKMET/GFS
Confidence: Average

A large scale trough over much of the central and western U.S.
with an East Coast ridge at the beginning of the forecast period
this morning will slowly translate eastward over the next few days
as the western Atlantic ridge retreats farther offshore.  The
leading edge of the height falls across the Ohio Valley and Great
Lakes will be accompanied by a strong cold front and surface low
that will herald a significant pattern change for the eastern U.S.
 There is very good model agreement on the timing of the front and
the passage of the strong surface low across the Great Lakes, so a
general model compromise can be incorporated with that system.

In the wake of the upper Midwest trough and surface low, there
will be a pair of shortwave troughs tracking southeast from 
central Canada, with one crossing the northern Plains and Midwest
Friday and Friday night, reaching the East Coast by Saturday
afternoon.  The 11/00Z ECMWF is now closer to the model consensus
and the GFS faster with the first shortwave, and the NAM remained
a strong and faster outlier. Across the West Coast, the guidance
continues to support a closed low evolving off the central
California coast by Friday morning and continuing through Saturday
evening. The 11/00Z NAM was most agressive in retrograding energy
off the West Coast compared with other global models, although the
10/12Z Canadian was aligned closer to the NAM than the GFS/EC
ensemble means/GEFS means.

Based on the latest model spread and clustering of solutions
across the continental U.S. for this period, combining elements of
the 11/00Z GFS/ECMWF/UKMET should be a good starting point that
captures the essence of the large scale flow pattern while
addressing differences in timing.


...Hurricane Michael...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: See the latest NHC forecast advisory

The 12Z ECMWF and GEFS mean are closer to the NHC track for
Michael than other models.  The 00Z NAM is also close to the NHC
track and timing as Michael transits the Southeast U.S. before
starting to lag by late in the day on Friday afternoon.


...Hurricane Sergio...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preference: See the latest NHC forecast advisory

A blend of the positions from the 00Z ECMWF/GFS are close to NHC
track through 13/00Z...then the 00Z GFS has a better fit to the
NHC track compared to other models.


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

Bann