US Day 3-7 Hazards Outlook NWS Weather Prediction Center College Park MD 344 PM EDT Wed May 20 2020 Valid Saturday May 23 2020 - Wednesday May 27 2020 Hazards: - Heavy rain across portions of the central Plains, Sat-Sun, May 23-May 24. - Heavy rain across portions of central to northern Texas, Mon-Tue, May 25-May 26. - Severe weather across portions of South Dakota and much of Nebraska, Sat, May 23. - Flooding possible across portions of the Southeast into the central and southern Appalachians, the interior Mid-Atlantic and the lower Great Lakes. - Flooding occurring or imminent across portions of the Lower Mississippi Valley, northeastern South Dakota, northern Washington, the Midwest, the lower Great Lakes, and the Ohio Valley. - Flooding likely across portions of the northern Intermountain region, the southern Appalachians, the lower Great Lakes, and the Ohio Valley. - Much above normal temperatures across portions of California into the central Great Basin, Tue-Wed, May 26-May 27. - Enhanced wildfire risk across portions of the the southern High Plains, Sat, May 23. - Heavy precipitation across portions of southern Alaska, Sat-Sun, May 23-May 24. Detailed Summary: The highly amplified synoptic pattern currently across the U.S. is expected to return to a more typical configuration by the medium range period (Saturday 5/23 - Wednesday 5/27). The cutoff upper-level low over the eastern U.S. should continue to gradually weaken and then move off the East Coast, ending the rainfall across the Mid-Atlantic by the weekend. Over the Pacific Northwest, the arrival of the next upper-level trough will usher in colder air through the northern Rockies behind a cold front, likely bringing a period of wet snow for the higher elevations of northwestern Wyoming into Saturday morning as a result. Severe thunderstorms are possible on Saturday across parts of the northern Plains although moisture ahead of the front appears to support only modest amounts of rainfall. As the cold front pushes further down the Plains, returning moisture from the Gulf of Mexico should raise the threat of heavy rainfall later on Saturday through Memorial Day across the central to northern Texas. The front is forecast to become nearly stationary early next week across the southern High Plains as the highest threat of heavy rain shifts farther to the south into Texas by Tuesday. Cooler than normal conditions are expected to spread across the northwestern U.S. toward the southern Plains behind the Pacific cold front in contrast with above normal temperatures across the Plains toward the Great Lakes ahead of the front. By next Tuesday into Wednesday, a warming trend is expected for a good portion of California into Nevada under a building ridge of high pressure where temperatures of about 15 degrees above normal are forecast. As for Alaska, a weakening occluded cyclone is forecast to bring heavy rain across the lower elevations of southern coastal sections including the Kenai Peninsula through Sunday. Snow is expected for the higher elevations. Above normal temperatures are forecast to persist across central Alaska, gradually spreading into the North Slope by the weekend but they do not necessitate a temperature hazardous area at this time. Ice jam flooding will be a concern over the North Slope as rivers have not yet broken up, while minor snowmelt flooding is a possibility in central and southern parts of the mainland. Kong