Extended Forecast Discussion NWS Weather Prediction Center College Park MD 214 AM EST Thu Feb 20 2020 Valid 12Z Sun Feb 23 2020 - 12Z Thu Feb 27 2020 ...Lead South-Central to Northeast U.S. storm Sunday-Tuesday Night to be closely followed by a wintry Northwest to Midwest/Northeast storm Sunday-next Thursday... ...Guidance/Predictability Assessment and Weather/Hazard Highlights... System #1: A potent southern stream system will reach the s-central Rockies/Plains Sun and then lift steadily northeastward to the Northeast by Wed. A swath of precipitation over the central Rockies/Plains into Sunday offers a snow/ice risk on the northern periphery of precipitation, including heavy mountain snows. Moderate precipitation will spread to the Mid MS/TN/OH Valleys, Appalachians and Eastern Seaboard Mon/Tue. There is an increasing risk for snow/ice on the northern periphery from the cooled Upper Midwest/Great Lakes to the Northeast. Models and ensembles have converged upon a more commonly supported solution with this system. System #2: A northern stream upper trough/surface system moving to the Northwest Sunday will dig through the Great Basin and Rockies Sunday and bring enhanced rain with heavy mountain snow with slow system progression/reinforcement. Downstream progression over the east-central states into next midweek offers an emerging pattern for moderate lead precipitation, but there would especially be a threat of heavy wrapback snows from the north-central Plains to the Midwest. Forecast spread is not ideal, but there is some signal in support of a significant secondary coastal low genesis from the Mid-Atlantic to New England next Wed/Thu. WPC progs offer modest system depth compared to some model guidance given flow and stream interaction uncertainties at these longer time frames. Expect much below normal temperatures over the central U.S. in the wake of this system with temperatures 15 to 25 degrees below normal. 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