Extended Forecast Discussion NWS Weather Prediction Center College Park MD 201 PM EST Tue Nov 10 2020 Valid 12Z Fri Nov 13 2020 - 12Z Tue Nov 17 2020 ...Tropical Storm Eta may have some affect on the Gulf Coast this weekend... ...Active pattern for the Pacific Northwest including a powerful system Fri-Sat... ...Overview... Quasi-zonal flow will maintain an active and progressive pattern during the period, characterized by changeable temperatures and bouts of precipitation, especially in the Pacific Northwest. In the Gulf, Tropical Storm Eta is forecast to lift northward later this week into the weekend but gradually fade. This may still bring some rain to the Gulf Coast but may very well be absorbed into the frontal boundary to its north, which could act as a larger area for forcing. See the National Hurricane Center for the latest information as the track later this week remains quite uncertain. The central states will see a lead area of rainfall Fri/Sat before clearing out, thanks to upper ridging. ...Guidance Evaluation/Preferences... The guidance was only in adequate agreement, but that varied on timing and track of a few systems. The 06Z GFS and 00Z ECMWF paired best with their ensemble means for much of the period, and that consensus was used as a starting point. Off the West coast, the 00Z Canadian/UKMET were quicker than the GFS/ECMWF cluster with the lead system Fri-Sat, though the trend was a bit quicker overall. With Eta, much depends on how strong it may become in the eastern Gulf and how it may get steered or left in weaker flow. Overall ensemble trend has been a little slower/more amplified for the mid-latitudes early next week, and the 00Z ECMWF was preferred by next Tue due to its slower progression across Canada and its weaker depiction of low pressure west of California as the 06Z GFS appeared too strong, but not implausible. ...Sensible weather and hazards... A potentially high impact storm system will likely affect the Pacific Northwest in the Friday-early Saturday time period. Heavy rain in the lower elevations, heavy snow in the higher elevations, and breezy/windy conditions throughout are becoming increasingly likely. Cool temperatures ahead of the system will moderate into next week as upper heights rise. Next system may linger astride the Washington coast early next week, maintaining the unsettled pattern. Frontal boundary in the Southeast Fri-Sun will act as a focus for rainfall out ahead of Eta, back to the Plains in advance of the strong Pacific system. Tropical Storm Eta could bring some rainfall to the Gulf Coast area, depending on its strength, track, and available moisture which may become limited as it weakens. Mild temperatures to start in the East, especially at night, will trend only a bit closer to normal by next week. Florida may seem some record high temperatures this weekend as highs reach the mid and upper 80s. Fracasso 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