Extended Forecast Discussion NWS Weather Prediction Center College Park MD 201 AM EST Fri Feb 21 2020 Valid 12Z Mon Feb 24 2020 - 12Z Fri Feb 28 2020 ...Active pattern for the eastern half of the CONUS next week... ...Overview and Guidance/Predictability Assessment... Upper ridging will settle into the West Coast next week with downstream reloading troughing favoring an active several days in the East. The 18Z GFS and 12Z ECMWF/Canadian clustered fairly well with the 18Z GEFS mean and 12Z ECMWF ensemble mean with the overall pattern through the week with a modest lead system Mon-Tue followed by a potentially much more robust system in the Northeast late in the week. For Mon-Tue, only the 12Z UKMET was displaced from the otherwise reasonable consensus of the other 12Z models, which was used as a starting point for the surface low lifting out of the Southern Plains/Mississippi Valley into the Midwest. On its heels will be a trailing front in the southern stream that may merge/phase or at least interact with the northern stream midweek. This slingshot/pinwheel effect could lead to rapid cyclogenesis near the Mid-Atlantic into the Northeast Wed-Thu. Though the evolution of such a system is contingent upon relatively smaller-scale features currently up near Alaska/North Pacific, the trend in the ensembles has been notable over the past four runs (especially the ECMWF ensemble mean). In order to trend judiciously toward a most likely scenario, utilized a 5-way blend of the 18Z GFS/GEFS mean and 12Z ECMWF/Canadian/ECMWF ensemble mean for next Thu/Fri as the system lifts through and then out of NY/New England. ...Weather/Hazard Highlights... The West will see generally above average temperatures given the upper ridge, with dry conditions for most areas and light rain/snow for parts of the Pac NW and northern Rockies early in the week. The central/eastern states will generally see near (early in the week) to below average temperatures (midweek to late in the week), at times 10-20 deg F below average behind the main cold front. Appreciable rain is likely for the Southeast Mon into Tue with some snow on the northwest side of the initial/lead surface low. The second system has more potential for wintry weather but is less certain in the details. Focus will be away from the coastal plain and rather along and west of the Appalachians. 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