Extended Forecast Discussion NWS Weather Prediction Center College Park MD 200 AM EST Sun Feb 16 2025 Valid 12Z Wed Feb 19 2025 - 12Z Sun Feb 23 2025 ...Intense Arctic Blast for the Central to Eastern U.S. next week with an impactful South-Central U.S. to East Coast Winter Storm... ...Guidance/Predictability Assessment... The WPC medium range product suite was primarily derived from a preferred blend at that time of best clustered guidance from the 18 UTC GFS/GEFS mean along with the 12 UTC ECMWF and ECMWF/Canadian ensemble means. Applied heavier blend weighting to the ensemble means into later week and next weekend to mitigate quickly growing flow embedded feature timing variances. This solution had strong machine learning model support and maintained good WPC product continuity. Outlier guidance from the 12 UTC Canadian/UKMET has since trended into the fold with the latest 00 UTC cycle, bolstering forecast confidence overall. ...Weather/Hazards Highlights... An impressive Arctic airmass will take hold over the central and eastern U.S. next week. Entrenched cold air will maintain lake effect snows and also offer a widespread threat of numerous record cold temperatures with focus over especially the central U.S.. Temperatures may be as cold as 25 to 45 degrees below average Wednesday for portions of the central and northern Plains. Upstream, several organized shortwaves/frontal systems will dig southeastward through the West. These systems will bring rounds of low elevation rain and mountain snow to the Pacific Northwest, Northern California, and the Northern/Central Intermountain West/Rockies. Fortified upslope fetch with the aforementioned Arctic frontal surge trough the central U.S. will favor lingering snow and wind to the lee over the High Plains/Rockies. As for heavy rainfall potential, the WPC Day 4/Wednesday Excessive Rainfall Outlook maintains an elongated Marginal Risk area from the central Gulf Coast through the eastern Carolinas as an organizing frontal wave track enhances moisture inflow. There will meanwhile be a threat for heavy snow/ice on the northern periphery of the rain area out from the Big South and through the Ohio/Tennessee Valleys. Downstream, an impactful winter coastal storm will offer a maritime threat, with wrapback winter storm potential from the Mid-Atlantic through New England Wednesday and Thursday as depicted on the WPC Winter Weather Outlook. With abundant sub-freezing temperatures in place ahead of this storm system, widespread snow is expected, with a corridor of mixed precipitation farther to the south. Guidance however still continues to adjust the storm track coastal proximity and inland extent of the bulk of precipitation. 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