Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EDT Fri Mar 14 2025 Valid 12Z Mon Mar 17 2025 - 12Z Fri Mar 21 2025 ...Guidance/Predictability Assessment... Models and ensembles overall seem reasonably well clustered with the main systems and mid-larger scale pattern evolution in active flow through much of the upcoming medium range forecast period for next week. However, numerous lingering smaller scale differences seems to favor preference for a composite guidance forecast plan, leaning somewhat more on the models for early next week for details before gradually switching midweek toward the ensemble means. This also seems generally in linw with the National Blend of Models and WPC continuity. ...Weather/Hazards Highlights... An amplified upper trough and lead/wavy cold front will exit the East Coast by Monday to moderate temperatures and sweep widespread thunderstorms out to sea; with possible low deepening out over the Western Atlantic as a possible maritime hazard. Temperatures are forecast to warm back up in the central and then eastern U.S. as the week progresses. This occurs with advent of upper ridging as a next main upper trough moves across the western and central U.S. early-mid next week and onward to the East later next week. Dyamically and terrain enhanced rain and elevation focusing snow is forecast to spread out from the West Coast to through the Interior West Monday-Tuesday. Cyclogenesis over the Plains on Tuesday and subsequent main/windy low track through the Midwest/Great Lakes into Thursday will combine with secondary cold frontal cooling to enhance upslope and wrapback plowable snow potential from the north-central Rockies/Plains through the Upper Midwest Tuesday- Thursday. A wavy trailing cold front will have less moisture than the early week system, but will align showers and thunderstorms across the central U.S. then the East, exiting next Thursday/Friday as new Pacific system energies and late winter precipitation work back into the West/Northwest. Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast (QPF), excessive rainfall outlook (ERO), winter weather outlook (WWO) probabilities, heat indices, and Key Messages can be accessed from: 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw