Extended Forecast Discussion NWS Weather Prediction Center College Park MD 201 AM EST Sat Feb 22 2020 Valid 12Z Tue Feb 25 2020 - 12Z Sat Feb 29 2020 ...Active few days for the eastern half of the CONUS next week... ...Overview and Guidance/Predictability Assessment... Western ridging and eastern troughing are favored in the medium range period, supported by Atlantic/Caribbean ridging and troughing east of Hawai'i. The models/ensembles were in good agreement through much of the period, focused mostly on the leading couple of frontal boundaries that are forecast to coalesce into a robust system over the Northeast. The 18Z GFS and 12Z ECMWF/GFS formed a reasonable cluster near their ensemble means for the Tue-Sun period. The 12Z UKMET/Canadian were close enough to be considered plausible but weighted only a small minority for the fronts/pressures starting point. Northern/southern stream interaction late Wed into Thu will likely lead to strong cyclogenesis over the Mid-Atlantic into the Northeast as has been seen for several runs and remains constant in the last several ensemble runs. Though the 12Z ECMWF may be too far west with its parent low Thursday it still lied within the multi-center ensemble spread (though the preference was a bit closer to the GFS). By the end of the week, uncertainty increases along/off the West Coast where a digging trough near 140W early Fri may either close off west of 130W (GFS/Canadian) or simply continue eastward (ECMWF). Ensembles were split between these two camps but had more support for the slower/closed solution, which fits the trends as well. Though strong upper ridging forecast to build toward the Gulf of Alaska teleconnects to troughing along the West Coast, the other anomaly centers do not. For now, will favor the slower solutions farther offshore but with lower than average confidence. ...Weather/Hazard Highlights... Some modest to locally heavy rain is expected across the Southeast (Fl/GA border) as the front moves through on Tue-Wed. Precipitation on the northwest side of the organizing fronts will support a swath of snow from the Corn Belt to the Great Lakes/Midwest. Once the system starts to deepen over the Mid-Atlantic, snow will expand across much of New York away from the coast and through northern New England. Temperatures will trend cooler with time as the system moves through, with the coldest readings (10-20 deg below average) progressing to the Appalachians and even down into Florida by Friday. By contrast, the West will see generally dry conditions next week. Temperatures about 10-20 deg above average (and even some record highs) can be expected. Light rain/snow will be confined to the coastal areas of WA/OR. 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