Extended Forecast Discussion NWS Weather Prediction Center College Park MD 159 AM EST Sun Nov 8 2020 Valid 12Z Wed Nov 11 2020 - 12Z Sun Nov 15 2020 ***Tropical Storm Eta expected to affect portions of southern Florida*** ***Cold and unsettled weather for much of the western U.S.*** ...Overall Synopsis... A broad upper level trough over the west-central U.S. next week is expected to be anchored in place through the end of the week, with multiple shortwaves/low pressure systems pivoting around it. The Bermuda high and the anomalous upper ridge near the East Coast will limit the eastward extent of the trough until next weekend, with the trough becoming situated over the Plains and the high moving farther offshore. Meanwhile, the Tropics remain active with tropical cyclone Eta expected to move slowly west of the Florida Keys after crossing Cuba. ...Guidance Evaluation/Preferences... The deterministic guidance is in good agreement on the overall pattern Thursday, after which timing and amplitude differences emerge across the western states. Both a southern and northern stream flow become evident in the models, and this flow separation is leading to the model differences being observed. By the end of the forecast period, the 00Z ECMWF becomes stronger with the trough emerging over the central Plains compared to the other guidance, and begins losing ensemble support for this degree of amplification. For the WPC fronts/pressures forecast, there was a gradual trend from a GFS/CMC/ECMWF blend to more of a NAEFS/EC mean blend by next weekend to mitigate the increasing model differences. ...Weather/Hazard Highlights... Tropical storm Eta is forecast to slowly track north and then western over the eastern Gulf, bringing heavy rain and potentially tropical-storm-force winds for portions of the southwestern Florida coast, but the worst conditions will likely remain offshore as the system begins to slow down and potentially stall, and both the timing and location of that remains highly uncertain. Meanwhile, the western U.S. trough will result in below normal temperatures for much of the interior western U.S. next week, with widespread high temperatures of 10 to 20 degrees below normal. An extended period of unsettled weather is forecast to move across the Pacific Northwest by the end of the week, with heavy mountain snows spreading eastward to the northern Rockies. Numerous showers, heavy at times, will also be likely west of the Cascades through much of next week under an active upper-level pattern across the northeastern Pacific. Mild late fall weather should continue across much of the eastern U.S. through much of next week, with temperatures that are expected to be 5 to 20 degrees above normal as the Bermuda high continues to govern the weather pattern. Moisture interacting with a slow moving front will likely bring a swath of heavy rainfall from the southern Appalachians to the Mid-Atlantic region for mid-week, followed by a return to drier conditions. Hamrick Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml