Extended Forecast Discussion NWS Weather Prediction Center College Park MD 316 AM EDT Fri Mar 22 2019 Valid 12Z Mon Mar 25 2019 - 12Z Fri Mar 29 2019 ...Guidance Assessment/Preferences... Latest models and ensembles seem compatable Mon/Tue and prefer a composite solution to smooth the less predictable smaller scale features. While guidance overall offers a fairly similar larger scale pattern evolution for the next week, run-run variance with a multitude of smaller embedded systems and stream interactions grows quickly. Accordingly, it seemed more prudent to favor an ensemble mean forecast approach days 5-7 and the WPC medium range product suite was primarily derived from a blend of latest GEFS/ECMWF ensembles. ...Weather Highlights and Hazards... This medium range period starts Monday/Tuesday as a southern stream front with several moisture/enhanced precipitation focusing waves ejects across the South/Southeast/and Mid-Atlantic. These waves cut underneath/interact with a cooling northern stream frontal drape whose post-frontal high pressure builds down through the central and eastern U.S. Meanwhile, a protracted series of Pacific systems with associated height falls and enhanced precipitation swaths will track onshore and across much of the West early through mid next week in advance of an mean closed low/trough reinforced just off West Coast. Expect heaviest precipitation/heavy mountain snows threats from northern California/Oregon to the northern Rockies. Indication that the bulk of Pacific trough energy will eject through the West Wed/Thu to emerge over the Plains later next week to induce cyclo/frontogenesis. This may occur just as a renewed northern stream may force cool air down into the unsettled n-central states. This airmass would prove to be in stark contrast to a rapidly warming airmass spreading over the e-central U.S. where moist Gulf return flow may fuel an expanding risk of enhancing rains/convection channeling between the surging fronts and retreating eastern U.S. high pressure. Schichtel 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