455 FXUS02 KWBC 171957 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 357 PM EDT Fri Apr 17 2026 Valid 12Z Mon Apr 20 2026 - 12Z Fri Apr 24 2026 ...Overview... An active weather pattern is expected next week with a deep upper low/trough moving into the West and shortwave energy ejecting across the Intermountain West and into the Plains. This pattern will push a strong frontal system across the West that will strengthen over the central U.S. mid-to-late next week and bring widespread precipitation chances with the potential for mountain snow. Cooler than average temperatures will persist through early next week in the Northeast while above normal temperatures develop across the Intermountain West and the Plains. Above normal temps should push into the east mid-week. ...Guidance/Predictability Assessment... Models remain in good agreement on the large scale pattern through early next week, with increasing uncertainty mid-to-late next week. The highest uncertainty surrounds shortwave interactions in the West, which will affect timing of surface features and sensible weather. Since the previous forecast, models have been trending a bit slower when pushing the initial system onshore in the West, resulting in a longer period of precipitation and higher precipitation totals for California. A blend of the available deterministic models served as a good starting point for the forecast, and ensemble means were added in increasing amounts Wednesday through Friday to help smooth out model differences. ...Weather/Hazards Highlights... Increasing return flow from the Gulf will support a broad axis of moisture convergence and instability along a frontal boundary over the Gulf, which will trigger convection over portions of Central, South, and East Texas on Monday and Tuesday. Locally heavy rainfall and isolated flash flooding may be possible, and there is a Marginal Risk of excessive rainfall for these areas in the Day 4/Monday and Day 5/Tuesday Excessive Rainfall Outlooks (EROs). Meanwhile, a Pacific frontal system will gradually push onshore, resulting in increasing precipitation chances along the West Coast Monday into Tuesday. Moderate rainfall and mountain snow are expected, with locally heavy rainfall possible in northern California that could lead to isolated flooding concerns. This flood threat is represented by a Marginal Risk of excessive rainfall for portions of northern California in the Day 4/Monday and Day 5/Tuesday EROs. The Pacific system will push across the Intermountain West on Wednesday and emerge in the Plains while strengthening Wednesday night into Thursday. Widespread precipitation chances and strong gusty winds will accompany this system, spreading from the Intermountain West to the Plains and Mississippi Valley. Accumulating snow will be possible across portions of the central and northern Rockies and into the Northern Plains. While impacts should be mainly confined to higher elevations, some travel impacts may be possible. The Desert Southwest and Southeast will experience mainly dry conditions next week, but isolated showers and storms will be possible for South Florida near a stalled frontal boundary. Isolated to scattered precipitation chances will also be possible along a relatively weak cold front from the Ohio Valley to New England early next week. Temperatures will trend below average early next week over much of the eastern U.S. in the wake of a cold front, and frost/freeze conditions will be possible Monday night for the Ohio Valley and central/southern Appalachians. Texas will also see below average temperatures as a result of forecast precipitation and cloud cover. Above normal temperatures will develop over much of central and western U.S. ahead of the strong frontal system, with the Rockies and Plains seeing high temperatures rise to 15-25 degrees above average. Mid-week, warmer temperatures will spread towards the East Coast while below normal temperatures spread from west to east behind the western frontal system. Dolan/Oudit 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, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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/#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 $$