Extended Forecast Discussion NWS Weather Prediction Center College Park MD 200 PM EST Fri Nov 06 2020 Valid 12Z Mon Nov 09 2020 - 12Z Fri Nov 13 2020 ...Tropical Storm Eta is forecast to impact southern Florida next Monday before tracking into the eastern Gulf and could head toward the Florida Panhandle by end of next week... ...Cold air across the West will gradually work its way toward the eastern U.S. through next week... ...Overall Synopsis... A deep upper level trough over the western U.S. should continue to work its way eastward across the nation through the upcoming week as tropical storm Eta is forecast to impact southern Florida early in the week. Meanwhile, the anomalous ridge over the central and eastern U.S. will give way to the approaching upper trough and allow Atlantic moisture to penetrate into much of the East Coast from the middle to the late next week, as Eta could potentially make landfall over the Florida Panhandle. ...Guidance Evaluation/Preferences... The WPC medium-range prognostic charts this morning were derived from a blend of the 00Z EC mean, 06Z GEFS, and a small portion from the 00Z NAFS. The 00Z ECMWF and the 00Z EC mean were very consistent with each other through the medium-range period. However, the 06Z GFS becomes increasingly fast regarding the low pressure waves riding along the front toward the Great Lakes from the middle to late next week. The 06Z GEFS was very agreeable with the 00Z EC mean though. Therefore, only a small portion of the 06Z GFS was included from Day 5 onward. In addition, the blend of the 06Z GEFS and the 00Z EC mean yielded a track of Eta very close to the NHC track for the medium-range period, lending confidence in adopting such a blend choice for today. ...Weather/Hazard Highlights... As tropical storm Eta is forecast to reach the Florida Key Monday morning, heavy rain and tropical-storm-force winds can be expected for southern Florida especially near the coast. The NHC has been keeping Eta on a track somewhere between the ECMWF and GFS, which will take Eta on a sharp turn to the left further away into the eastern Gulf later on Monday into Tuesday. Most models indicate a decrease in QPF for Florida as Eta pulls further offshore, and presumably adopting a sheared/hybrid structure by then. The persistent western U.S. trough will result in much colder temperatures for much of the interior western U.S. next week, with widespread high temperatures of 10 to 20 degrees below normal. This will easily be a 30+ degree drop for some areas compared to the recent warm spell. Heavy snow will be possible for portions of the Colorado Rockies and the Cascades. The opposite will hold true across the eastern U.S. through much of next week, with temperatures that are expected to be 10 to 20 degrees above normal from the Midwest and Great Lakes region, and extending to the East Coast. Some daily record high temperatures will be challenged, especially over the Ohio Valley. As the trough axis slowly advances eastward across the High Plains by early next week, moisture interacting with the front will likely bring locally heavy rainfall to some locations across the central Plains to the Midwest, with a swath of wintry precipitation possible for the northern portion of the area. Noteworthy rainfall is also possible for portions of the Southeast and Mid-Atlantic region towards the end of the week as the front slowly approaches this region. Kong/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