Extended Forecast Discussion NWS Weather Prediction Center College Park MD 146 AM EST Wed Nov 13 2019 Valid 12Z Sat Nov 16 2019 - 12Z Wed Nov 20 2019 ...Pattern Overview and Guidance/Predictability Assessment... Upper pattern will transition toward western troughing and eastern quasi-zonal flow in about a week, after a two successive systems lift northeastward along the East Coast. In the West, upper ridging will weaken as it slides eastward atop a closed upper low moving away from Baja California. This will pave the way for a Pacific shortwave to dig through interior California as downstream heights rise in response. Off the Southeast coast, the models have come into better agreement with mostly some timing differences as it looms offshore. Model blend sufficed given recent shifts in the ECMWF/GFS. 12Z UKMET/Canadian were close enough to the ensemble range as well. Upstream system will act to kick the lead shortwave along, but reinforce the surface boundary along the Gulf Stream. This may develop another low and off the NC coast which should move quicker out to sea as heights rebound. In the West, lead front into Washington will weaken in favor of a stronger shortwave on its heels. The ECMWF has been most aggressive with this feature and dug it farther southwest than the other guidance. GFS has been more in line with the ensembles but given how much upstream ridging is forecast to build into the Gulf of Alaska, the ECMWF solution cannot be ruled out completely. This would carry a cold front through the Great Basin into the Four Corners region by next Wednesday. ...Weather Highlights/Threats... Below average temperatures in the East will slowly moderate back toward more typical mid-November values by early next week. Much of the West will have temperatures above normal by 5-15 degrees through this weekend, cooling early next week with the arrival of the next upper trough. The system off the Southeast/mid-Atlantic coast should keep the heaviest rains offshore but should be close enough to produce at least showers along the I-95 corridor. Heavier rain is possible right along the coast of North Carolina. The strong pressure gradient between the low sfc high over New England will lead to windy conditions along the coast. The precipitation shield will move northward into New England early next week where temperatures may be cold enough for some snow in higher elevations. Several systems out of the Pacific will maintain a rather wet period for at least coastal Washington/Oregon and the Cascades, with less rain/snow along and just west of the Continental Divide. With increased troughing toward the Southwest next week, some light precipitation will be possible late Tue into 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