Model Diagnostic Discussion NWS Weather Prediction Center College Park MD 1242 PM EDT Wed Oct 10 2018 Valid Oct 10/1200 UTC thru Oct 14/0000 UTC ...See NOUS42 KWNO (ADMNFD) for the status of the upper air ingest... 12Z Initial Model Evaluation...with latest preferences and confidence ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ...Overall Pattern Across the CONUS... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: Blend of the 12Z GFS/UKMET/00Z EC mean Confidence: Slightly above average A large scale trough over much of the central and western U.S. and an East Coast ridge at the beginning of the forecast period Wednesday is forecast to 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 through Friday night, and then reaching the East Coast by Saturday afternoon. The second shortwave will then amplify down across the northern High Plains by Saturday night. The ECMWF is slower than the model consensus and the GFS faster with the first shortwave, and the NAM is stronger and faster with the second shortwave, similar to its earlier runs. The EC mean provides a reasonable placement for these features, with a magnitude similar to the GFS. 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 00Z NAM continues to retrograde more energy off to the west compared to the global models. Based on the latest model spread and clustering of solutions across the continental U.S. for this period, a blend of the 00Z EC mean, 00Z UKMET and 12Z GFS will be preferred. ...Hurricane Michael... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: See the latest NHC forecast advisory Powerful Hurricane Michael will lift north and be crossing the FL panhandle within the next 12 hours, and will then rapidly recurve northeastward across the interior of the Southeast and the southern Mid-Atlantic states through the 36 hour time-frame. The 00Z ECMWF trended faster with this cycle and now closer to the 12Z GFS with the track of Michael through 48 hours. Thereafter, as the storm exits the Mid-Atlantic coast, the ECMWF and CMC are among the slowest solutions, and the CMC is weaker. Meanwhile, the 12Z NAM and 12Z GFS solutions are the fastest solutions with the track of Michael. ...Hurricane Sergio... ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Preference: See the latest NHC forecast advisory The global models all continue to indicate Hurricane Sergio tracking off to the northeast toward the central Baja California peninsula over the next couple of days, with the storm likely making a landfall on Friday. Thereafter, the storm will begin to lose its identity and intensity as it traverses northwest across mainland Mexico, but its moisture and remnant mid-level energy will impact portions of the Southwest and also the southern Plains. The 12Z GFS is the fastest solution to make landfall, whilst the ECMWF and the EC mean are on the slower side of the guidance. Model trends at www.wpc.ncep.noaa.gov/html/model2.shtml 500 mb forecasts at www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml D. Hamrick