Extended Forecast Discussion NWS Weather Prediction Center College Park MD 147 PM EST Thu Nov 12 2020 Valid 12Z Sun Nov 15 2020 - 12Z Thu Nov 19 2020 ...Overview... Progressive and amplified pattern will continue next week over the lower 48. Initial trough in the Upper Midwest will lift into southeastern Canada early Monday and then off the East Coast, ushering in cooler and drier conditions. Upper ridging will coalesce into northern Mexico from the east and west as another Pacific trough digs off California and moves inland. ...Guidance Evaluation/Preferences... Through the 00Z/06Z cycle (minus the 06Z GFS which was not fully available), the guidance was in good agreement overall except for the incoming system into Oregon early Sunday. The 00Z ECMWF/ECMWF ensembles were quicker and weaker with the system than the 00Z GFS/Canadian/UKMET/continuity. Stuck with the slightly slower guidance but was not as strong, though the newer guidance has trended a bit quicker. Over the Great Lakes, robust system will lift out of the western Great Lakes/U.P. of Michigan across southern Ontario and into Quebec, dragging its cold front eastward off the East Coast and through the Gulf/Florida by early Monday. By next Tue-Thu, models still show a large amount of disagreement on the evolution, track, and strength of the surface system off the West Coast. Ensemble means continued to be quicker than the deterministic models, which were spread east-west over several hundred miles. Again preferred to stick closer to the middle of the guidance around the 00Z ECMWF, but not as slow. This would take the main low pressure toward Vancouver Island late Tue into early Wed as the cold front moves through the Northwest. Lingering troughing is expected off California into next Thu as the northern part of the system continues eastward across southern Canada, dragging its front through the High Plains but settling across the Great Basin as the upper flow stays west-southwesterly. Trended toward an ensemble mean preference with only a minority weighting of the 00Z ECMWF for the Wed-Thu period next week amid the uncertainty in the West. ...Sensible weather and hazards... Moisture plume with modest to locally heavier rain/snow amounts into the Pacific Northwest this weekend will trend southward with time through Oregon into northern California as the next system comes through. Precipitable water values rise to a maximum over 1 inch as subtropical connection (atmospheric river) feeds into western WA/OR late Mon into Tue. Temperatures near normal will trend a bit higher through the week via the mild Pacific flow. The eastern U.S. will see initially above normal temperatures dip below normal in the wake of the frontal passage, especially around next Tue/Wed. Rain and some high elevation snow Sunday will wane in the Northeast, except for downwind of the eastern Great Lakes which will see some lake-enhanced precipitation. A the cold front pushes well south into the Caribbean, cooler temperatures and drier conditions will spread through Florida with temperatures in the 70s and dew points around 50 over northern areas to the low 60s across South Florida around the middle of next week. 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