Extended Forecast Discussion NWS Weather Prediction Center College Park MD 136 PM EST Mon Nov 02 2020 Valid 12Z Thu Nov 05 2020 - 12Z Mon Nov 09 2020 ...Hurricane Eta to track slowly through the Caribbean... ...Heavy rain possible over southern Florida... ...Heavy precipitation for the Pacific Northwest and wintry weather through the West/Rockies/Northern Plains... ...Overview... Developing deep troughing over the western U.S. will result in an increase in active weather across portions of the CONUS through the medium range period. Meanwhile, Hurricane Eta is forecast to make landfall in Central America and then could stall or lift back to the north/northeast late in the forecast period. Much uncertainty exists in the forecast beyond day 5 with this system. Regardless, deeper tropical moisture may interact with a frontal system to the north and bring periods of rainfall to Florida, some of which could be heavy. ...Guidance Evaluation/Preferences... Much of the deterministic guidance began in good agreement and the WPC blend started off with a near equal weight of the 00Z ECMWF/UKMET/CMC and 06Z GFS. However, for the western U.S. troughing, the GFS was a faster solution, with its associated surface low east/ahead of the other deterministic guidance. The ECMWF and its ECENS mean showed good consistency and also to the previous forecast and therefore was utilized heavily for days 5-7. ...Weather/Hazard Highlights... A potent mid/upper trough will work through the interior West and northern Rockies, bringing a significant cooldown and bouts of winter precipitation. There is potential for a significant precipitation event across portions of the Northern Rockies where the latest winter weather probabilities for exceeding 0.25" liquid equivalent in snow/sleet exceeds 70 percent on day 5-6. Temperature departures behind the system are forecast to be 20-30F. Meanwhile, ahead of this system across much of the central/eastern U.S. there should be moderating temperatures that then trend to 10-20F above normal as high pressure holds over the Southeast. As the trough axis works into the central/northern Plains on Day 7 (Monday Nov 9), moisture interacting with the front could bring locally heavy rainfall to some locations. Elsewhere, heavy rainfall is possible across southern Florida as moisture interacts with easterly post-frontal flow well to the north of Eta and any possible additional tropical development. Taylor 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