Model Diagnostic Discussion
NWS Weather Prediction Center College Park MD
254 PM EDT Thu Oct 11 2018

Valid Oct 11/1200 UTC thru Oct 15/0000 UTC

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

12Z Model Evaluation...with latest preferences and confidence
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...Overall Pattern Across the CONUS... 
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Preference: Blend of the 12z GFS and 00z ECMWF/UKMET
Confidence: Average

19z Update: The 12z ECMWF is a bit slower compared to the GFS with
the shortwave trough advancing through the Mid-Atlantic Friday
night into Saturday. It is also slower with the closed low moving
into ND/MN by the end of forecast period (Sunday). There are some
strength differences with the shortwave digging across the
Inter-mountain West.

With the energy from Sergio moving into the south-central Plains,
while the upper level pattern is in good agreement, there are
differences at the surface. The NAM was further south compared to
the GFS, with the ECMWF a bit to the north.

---Previous Discussion---
The general pattern across the CONUS will feature a longwave
trough moving across the central/eastern US, while current TS
Michael becomes absorbed in the flow and accelerates northeast off
the Atlantic coast. A couple of shortwave troughs will dig and
trek across the north-central US into the Mid-Atlantic/Northeast
this weekend. A persistent ridge will build further off the
western US coast while a closed low is forecast to drift onshore
across southern California.

There is good model agreement on the frontal passage across the
Mid-Atlantic and Northeast US through tomorrow and also with the
high pressure building in across the central Plains. Based on the
latest model spread and clustering of solutions across the
continental U.S. for this period, combining elements of the 12z
GFS with the 00z ECMWF/UKMET should be a good starting point that
captures the essence of the large scale flow pattern while
addressing differences in timing.

...Tropical Storm Michael...
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Preference: See the latest NHC forecast advisory

There is good clustering in the global models that show Michael
exiting off the Mid-Atlantic coast tonight. Some timing
differences develop by Friday night with the GFS/NAM a bit faster
than the ECMWF/CMC, but overall the spread is fairly minimal as
the storm accelerates northeast.


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

The 12z GFS is most closely aligned to the current NHC advisory
track, bringing Sergio into the Baja California peninsula Friday
morning. The storm is forecast to weaken and dissipate as it lifts
into mainland Mexico, losing its identity while getting absorbed
within the large scale upper level flow. A blend of the
GFS/ECMWF/UKMET looks like a reasonable proxy for the official
track.


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

Taylor