Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
239 AM EDT Tue Oct 09 2018

Valid Oct 09/0000 UTC thru Oct 12/1200 UTC

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

00Z Model Evaluation...with latest preferences and confidence
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...Overall Pattern Across the CONUS... 
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Preference: Blend of the 00Z GFS/ECMWF
Confidence: Slightly above average

A highly amplified pattern across the CONUS will continue through
Tuesday as a deep longwave trough evolves over the Western U.S.
and a strong subtropical ridge remains intact across the Eastern
U.S. By Wednesday, the ridge across the Eastern U.S. will begin to
retreat eastward and this will allow height falls to eject well
out across the Plains and Midwest. The guidance though agrees in
reinforcing a broad trough over the West through Thursday as
additional shortwave energy drops southward down from Southwest
Canada and into the Intermountain region.
 
Regarding the details, the models all agree in shifting the
longwave trough east across the Plains and toward the Midwest
which will allow a cold front to advance east toward the MS Valley
and with low pressure lifting up across the upper Midwest. By
Thursday, the front will advance well east across the OH/TN
Valleys, as low pressure deepens up across the upper Great Lakes
region. The 00Z NAM/CMC solutions are somewhat stronger than the
00Z GFS/UKMET/ECMWF solutions regarding the strength of the upper
trough. And with respect to the surface low, the CMC tends to be
on the west side of the model spread. The latest GEFS mean and
ECENS mean support the GFS/UKMET/ECMWF cluster.
 
Elsewhere across the CONUS, the guidance digs multiple shortwave
troughs across the Western U.S., as energy drops south from
British Columbia. This will lead to a possible closed low
evolution down toward parts of the southern Great Basin and CA by
the end of the period, and will be a player in helping to recurve
Hurricane Sergio over the eastern Pacific off to the northeast
across the Baja Peninsula on Friday. The guidance is relatively
well-clustered with the height fall evolution, although the 00Z
NAM is a bit northwest of the global models with its closed low
just offshore central CA. Regarding the new northern stream
shortwave trough across the upper Midwest by Friday, the 00Z UKMET
is a bit slower than the consensus, and the 00Z NAM is a bit
faster. The 00Z GFS/ECMWF solutions are well clustered in between
camps.

Based on the latest model spread and clustering of solutions
across the CONUS for this period, a blend of the 00Z GFS/ECMWF
solutions will be preferred.


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

The guidance all agrees in taking Hurricane Michael northward
across the eastern Gulf of Mexico over the next 36 hours with a
landfall likely occurring over the FL panhandle by around 48 hours
if not sooner. A recurvature to the northeast across the Southeast
and southern Mid-Atlantic region is expected thereafter through 72
hours. The 00Z CMC/UKMET solutions are overall the fastest
solutions with Michael, although the CMC is a bit left of the
model consensus as the system lifts north over the Gulf of Mexico.
Thereafter, the CMC weakens Michael much more rapidly than the
other global models. The 00Z NAM by 36 hours begins to edge a bit
right of the consensus and also tends to be a little slower than
the model consensus. The 00Z GFS/ECMWF solutions are on the slow
side of the model spread, and after 48 hours, the ECMWF becomes
the slowest solution of all the guidance. The GFS and ECMWF though
are well clustered up to the 48 hour time frame. The 03Z NHC
forecast track is very close to the 00Z UKMET and thus is a bit
faster than the model consensus. Please consult the latest NHC
forecast advisory for more details on Hurricane Michael.


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

The global models all continue to agree on recurving Hurricane
Sergio off to the northeast toward the central Baja California
peninsula over the next few days, with the storm likely making a
landfall here on Friday. The 00Z UKMET is the fastest solution,
with the 00Z ECMWF the slowest. The 00Z NAM/GFS/CMC solutions are
clustered in between. The 03Z NHC forecast track is a bit faster
than the model consensus and is close to the UKMET.


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

Orrison