Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1139 AM EDT Mon Mar 11 2019 Valid 12Z Thu Mar 14 2019 - 12Z Mon Mar 18 2019 ...Heavy snow/wind threat to exit the North-Central U.S. Thursday... ...Heavy rain threat in the Southeast Thursday... ...Overview and Guidance Assessment/Preferences... The ridging over the western U.S. and Canada will support the trough persisting over the eastern half of the CONUS over the course of this coming week. A robust winter storm system will lift northeast from the Central Plains through the Great Lakes/Northeast by late Friday. The trailing flank of this frontal boundary will stall and linger over South Florida and the Gulf of Mexico. A series of systems will track through the Gulf of Alaska/North Pacific and weaken as they approach the Pacific Northwest Coast. The models/ensembles continue to show reasonable clustering through the period and a blend of the GFS/ECMWF with their ensemble means offered a good starting point that kept in line with continuity. The CMC and its ensemble means were largely discounted for much of the extend periods as it initialized well to the north/northwest of the rest of the cluster. ...Weather Highlights and Hazards... Low pressure over Iowa Thursday morning will bring strong, gusty winds that will cause blowing and drifting snow across the Upper Midwest and then Great Lakes as it exits through Ontario and Quebec on Friday. To the south, influx of Gulf moisture will support a continued threat for heavy rainfall and embedded convection from Alabama/Mississippi eastward as the cold front continues to move eastward and southward. Mild air drawn northward ahead of the front will be replaced by much cooler temperatures (5-10 degrees below average) that will finally exit out of the west and focus on the central states. By Sat-Mon, high pressure will be in control of much of the lower 48 with a dry northwest flow out of Canada, supporting some lake-enhanced snows. Campbell 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