FXUS01 KWBC 181933 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 332 PM EDT Mon May 18 2026 Valid 00Z Tue May 19 2026 - 00Z Thu May 21 2026 ...Severe weather and flash flooding threats continue across the Central Plains and Midwest into tonight before shifting south and eastward through midweek... ...Extreme fire weather concerns across the southern High Plains through this evening... ...Heavy wet snow continues across the Central Rockies before tapering off tonight... ...An early-season heatwave will challenge temperature records across the eastern U.S. through Wednesday... A strengthening frontal system will be the focus for another round of severe weather and flash flooding across the Central Plains and Midwest into tonight. Rich moisture streaming northward from the Gulf will interact with a wavy, slow-moving cold front draped from the Upper Midwest to the southern Plains, triggering numerous showers and thunderstorms this afternoon and evening. This activity will be bolstered by an extremely unstable air mass, setting the stage for thunderstorms to become strong to severe. The greatest threat for severe storms will be across the Central Plains and the mid/southern Missouri Valley where the Storm Prediction Center has maintained a Moderate Risk (level 4/5) of severe weather. The most intense storms will be capable of producing damaging winds, very large hail, and a few potentially strong tornadoes. In addition to the severe threat, there is also a heightened risk of heavy rain and flash flooding, especially across parts of Missouri, Iowa, Nebraska, and Kansas. Slow-moving clusters of storms will produce numerous downpours with rainfall rates of 1-3"/hr. These drenching storms will likely repeatedly track over the same areas, leading to an increased risk of flash flooding. As a result, the Weather Prediction Center continues to highlight a Moderate Risk (level 3/4) of excessive rainfall through tonight. The frontal system begins to pick up speed as it pushes eastward, shifting the severe weather and heavy rainfall threat to the Southern Plains, Ohio Valley, and Mid-Atlantic Tuesday into Wednesday. Meanwhile, a late season winter storm continues to bring heavy mountain snow to the Central Rockies this afternoon. Snow will continue through this evening before gradually tapering off tonight. Several inches of heavy wet snow accumulation will be measured once snow comes to an end. Unseasonably cold air will follow in the wake of the storm, leading to frost and freeze concerns from the Intermountain West to the northern High Plains tonight into early Wednesday morning. On the hotter and drier flank of this dynamic and multifaceted storm system, the concern shifts to extremely critical fire weather conditions across portions of the southern High Plains this afternoon and evening. Strong gusty winds combined with susceptible fuels and relative humidity values in the single digits and teens will support the ignition and extremely rapid spread of new and ongoing wildfires. These critical conditions could become exacerbated when a cold front sweeps southward and rapidly shifts surface winds from westerly to northerly later this afternoon and evening. With snow, severe, and fire weather in full swing across the Rockies into the Plains, the Eastern U.S. is entering an early-season heatwave. A Bermuda high pressure system will remain anchored over the western Atlantic, steering a long fetch of warm, southerly flow across the eastern half of the country. High temperatures will soar well into the 80s and 90s the next few days, challenging high temperature records across parts of the Ohio Valley, Mid-Atlantic, and Northeast. Widespread moderate to major HeatRisk is forecast, highlighting the season's first extended period of potentially hazardous heat for millions across the Eastern U.S. Miller Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$