342 FXUS01 KWBC 171959 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sun May 17 2026 Valid 00Z Mon May 18 2026 - 00Z Wed May 20 2026 ...Multi-day severe weather and flash flood threat continues across the Midwest and Plains... ...Extreme fire weather concerns across the southern High Plains today into Monday... ...Heavy wet snow blankets the higher-elevations of Wyoming, the Front Range, and the Wasatch Sunday night into Monday... ...Well above average, hot Summer-like temperatures will continue into the first half of the week across the eastern U.S.... An amplifying upper-level pattern featuring an energetic upper-trough digging across the western to central U.S. will provide the trigger for multiple days of severe weather and heavy rain/flash flooding across the Plains and Midwest. A similar set up will be in place day-to-day as southerly flow ahead of the upper-trough has brought plentiful Gulf moisture northward ahead of a slow moving cold front/dryline with daytime heating leading to strong instability. Favorably timed embedded short-waves within the fast flow of the upper-trough will provide more than sufficient shear to promote the development of robust, severe thunderstorms. For today (Sunday), the greatest threat is across portions of the Upper Midwest/Middle Missouri Valley southwest through the central Plains where there is an Enhanced Risk of severe weather (level 3/5) from the Storm Prediction Center for the threat of very large hail, significant damaging winds, and multiple tornadoes, some of which could be strong. The intense storms will also be capable of heavy downpours with a risk of isolated flash flooding across the Upper Midwest/Middle Missouri Valley. For tomorrow, the threat shifts a bit southeast ahead of the slowly progressing cold front with an Enhanced Risk from the Middle/Lower Missouri Valley southwest into portions of the central/southern Plains for the continued threat of very large hail, significant damaging winds, and tornadoes. A focused corridor with a higher threat for intense tornadoes and giant hail has been noted across portions of central/eastern Kansas into southeastern Nebraska, where the outlook has been upgraded to a Moderate Risk (level 4/5). Additional more scattered severe storms capable of large hail, damaging winds, and a few tornadoes are possible into the Great Lakes region with a Slight Risk (level 2/5) in place. The front will speed up to the east by Tuesday with clusters/organized lines of thunderstorms forecast to develop from the Great Lakes southwest through the Middle Mississippi Valley and into the southern Plains. Lower instability and the progressive front will lessen the threat for severe weather compared to Monday, though some large hail and damaging winds will remain possible, with a broad Slight Risk in Place. Heavy rain will also remain possible, though the faster moving front should limit rainfall duration leading to just an isolated risk of flash flooding. Meanwhile, hot temperatures into the 90s to near 100, very low relative humidity, and gusty winds behind the dryline have prompted an Extreme Risk of fire weather from the SPC (level 3/3) for portions of the Southern High Plains today as well as Monday. Quick starting and fast moving, dangerous wildfires are possible. The deep upper-trough will also bring a fairly widespread and heavy late season snow event to higher elevations of the regional mountain ranges throughout much of the Intermountain West, particularly for Wyoming, the Colorado Front Range, and the Wasatch Sunday night into Monday. Totals locally higher than a foot will be possible. Some snow may mix in for some of the higher mountain valleys and along the immediately adjacent northern High Plains, though little to no accumulations are expected. Elsewhere, thudnerstorms are expected for central/south Florida the next couple of days, with some isolated flooding possible in urban areas of southwest Florida today. Scattered thunderstorms are also possible for the Southeast Monday. The amplifying pattern with a building upper-ridge over the central to eastern U.S. will continue to lead to above to well above average, hot temperatures more reminiscent of Summer than mid- to late Spring. Widespread highs into the upper 80s to 90s are forecast ahead of the cold front from the Plains/Midwest through the Mississippi Valley and to the East Coast. Many daily record-tying/breaking highs will be possible especially as temperatures reach into the low to mid-90s across the Upper Ohio/Tennessee Valleys into the Carolinas, Mid-Atlantic, and southern New England. To the west, much colder, chilly May temperatures are forecast behind the cold front over the Intermountain West with highs mainly in the 40s and 50s. These temperatures will progressively spread eastward across the northern/central Plains into the Upper Midwest as the front moves eastward the next couple of days, with highs only reaching into the 30s for areas of eastern Wyoming Monday. Frost and Freeze related Advisories/Warnings are in place across portions of the northern to central High Plains for Tuesday morning. The temperatures will moderate as they spread further eastward but provide a stark change compared to the heat ahead of the front, with highs in the 50s further north and 60s into the low 70s further south. The West Coast will see a warm-up to start the week as the bulk of the upper-trough shifts eastward, with highs climbing into the 60s and 70s along the coast and 80s and 90s for inland California. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$