Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1258 PM EST Wed Nov 11 2020 Valid 12Z Sat Nov 14 2020 - 12Z Wed Nov 18 2020 ...Active weather pattern for the West... ...Overview... Troughing in the central states will push eastward, allowing ridging to build in next week from the Rockies. The pattern will remain progressive yet still robust as a strong area of low pressure lifts through the Upper Midwest/Western Great Lakes early Sunday into Canada. Another Pacific system is forecast to move into western Washington at the same time, followed by a potentially stronger one around next Tuesday. The East will see quieter conditions next week as a cold front pushes all the way through the Gulf of Mexico. The remnants of Eta will be absorbed into a frontal boundary off thee Carolina coast by the start of the period early Saturday. ...Guidance Evaluation/Preferences... Through the 06Z/00Z cycle, the deterministic models offered a reasonably-clustered starting point for the fronts/pressures into early next week. Trend has been a bit quicker in the Sat-Sun period for the system out of the northern Rockies but otherwise maintained good continuity. By next Tue-Wed, spread increases rapidly in the eastern Pacific with the next upper trough and surface low pressure (or multiple waves). Preferred the 00Z ECMWF over the quicker/farther east 06Z GFS and farther northwest Canadian, through no model has been consistent on timing or discerning one vs multiple areas of low pressure eventually carrying the front into the Pac NW. Therefore, relied heavily on the ensemble means as a basis for the latter periods but included continuity and a smidgen of the ECMWF/GFS since their forecasts in the East were reasonable. ...Sensible weather and hazards... Coastal Washington/Oregon will see a wet period into next week with continued onshore flow and frontal passages. Early Sunday will see an enhancement to the rain/snow over the Northwest as an area of low pressure moves inland, focused on the Cascades and coastal ranges of WA/OR as well as northern Idaho. With the frontal boundary lingering through the area, precipitation will continue on and off early next week with another potentially more organized event next Tue/Wed. With a deeper trough, this could bring appreciable rain and mountain snow into the Sierra and coastal northern California. Spread in the guidance remains modest for a 7-day lead time as some ensemble members spread rainfall southward through central and southern California as well. Temperatures will be near to below normal to start the period but trend a bit milder with time along and west of the Rockies. Temperatures in the Plains will start milder ahead of the lead front before cooling in its wake. Expect another warm-up there next week in advance of the next system. The East is forecast to trend much quieter after the weekend, once the cold front pushes through late Sunday. The heaviest rainfall/snowfall will follow near the low pressure center through Canada (initially over the Great Lakes) as moisture from the Gulf will be quite limited in the wake of Eta's departure with the southern front. Temperatures near to above normal this weekend will turn cooler behind the front, especially over the Midwest next Tuesday. Some lake-enhanced rain/snow is likely early next week behind the Canadian low but otherwise little precipitation is expected in the East next Tue/Wed. 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