Extended Forecast Discussion NWS Weather Prediction Center College Park MD 155 PM EST Sat Nov 07 2020 Valid 12Z Tue Nov 10 2020 - 12Z Sat Nov 14 2020 ...Tropical Storm Eta could affect Florida next week while moisture streaming north of it could cause heavy rain over the Eastern Seaboard... ...Unsettled weather continues in the Northwest, with precipitation increasing especially later in the week... ...Overview... A longwave upper trough is forecast to be situated over the west-central CONUS through next week, with multiple shortwaves rotating through it. This troughing may push toward the East late in the week, overcoming the Bermuda high and warm subtropical ridge. Meanwhile, Tropical Storm Eta is expected to move into the eastern Gulf of Mexico by the middle of next week, which could cause hazards particularly over Florida. ...Guidance Evaluation/Preferences... Model guidance was in generally good agreement with the overall trough pattern gradually shifting eastward through the week. Additionally, the initial shortwave and surface low moving northeastward across the central U.S. toward the Great Lakes Tue/Wed were well clustered in the deterministic guidance. Thus, for the first part of the forecast period, a multi-model deterministic blend of the 00Z and 06Z guidance was able to be used. Differences arise with the shortwaves moving through the trough during the latter part of the week. One shortwave is forecast to move through the Northwest Tue and north-central U.S. Wed/Thu (with reasonable model agreement), but by Fri, GFS runs have deepened that shortwave then tracking across the Midwest/Ohio Valley more than the EC/CMC. On the other hand, the 00Z ECMWF emphasizes a much more energetic shortwave coming through the western and then central CONUS Fri/Sat. At this point, did not seem wise to favor one solution over another and leaned toward the EC and GEFS ensemble means for the WPC blend. Favored the 06Z GEFS mean just a bit heavier as it had a little more depth to both of the aforementioned shortwaves. The WPC forecast followed the National Hurricane Center track for Eta. The 00Z and 06Z deterministic GFS runs were faster and farther east than non-NCEP guidance, potentially making landfall in the northern Florida peninsula by Wed, unlike the other guidance which is slower in lingering the tropical cyclone over the Gulf. The 12Z GFS came in slower and more in line with other guidance, however, so slower seems to be the trend. Regardless, uncertainty in Eta's track and strength remains, as there is a good amount of spread in ensemble members as well. ...Weather/Hazard Highlights... Tropical Storm Eta is currently forecast to move into and track somewhat slowly across the eastern Gulf of Mexico during the medium range period, so it could continue to affect some areas of Florida in particular with heavy rain and tropical-storm-force winds. Any landfall location and timing for Eta is too uncertain to determine at this time. See the National Hurricane Center for updates on Eta. A potent cold front will track eastward across the central U.S. Tue toward the eastern U.S. as the week progresses. A round of moderate to locally heavy rainfall is possible across portions of the Middle/Upper Mississippi Valley and Upper Great Lakes region Tue, and precipitation could switch over to mixed precipitation or snow in the northwestern part of the precipitation swath. Then, tropical moisture streaming north of Eta as well as Atlantic moisture may combine in the vicinity of the front as it moves eastward, causing the potential for heavy rainfall in the Appalachians toward portions of the Eastern Seaboard during the second half of the week. Ahead of the cold front, widespread and record-setting warmth is expected, with temperatures of 15 to 30 degrees above normal shifting from the Upper Great Lakes Tue toward the Appalachians and Eastern Seaboard. In fact, hundreds of daily record temperatures could be set next week in the central to eastern U.S., with some record maximum temperatures but particularly with record warm minimum temperatures. Meanwhile in the West, cool weather with periods of precipitation is expected. Temperatures of about 10 to 20 degrees below normal are forecast for the western half of the CONUS especially through Thursday, with some moderation after that time likely. Unsettled weather should lead to light to moderate precipitation especially in higher elevations of the Northwest through about Thu. Then, moist onshore flow is forecast to increase by late week and lead to heavier precipitation for the northwestern quadrant of the country, with the potential for heavy snow in higher elevations of the Cascades and Northern Rockies as well as persistent lower elevation rain. Tate 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