Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Sun Apr 27 2025 Valid 00Z Mon Apr 28 2025 - 00Z Wed Apr 30 2025 ...Heavy rainfall and snowmelt bring flooding concerns to portions of the northern High Plains of Montana today... ...Outbreak of severe weather, including strong tornadoes, expected for portions of the Midwest/Plains Monday... ...Threat of potentially significant flash flooding returns to portions of the southern Plains Tuesday... ...Warm, well above average conditions to start the week for much of the central/eastern U.S.... Our ongoing Spring weather pattern across the U.S. will bring increasingly active weather into the mid-section of the country as we head into the new week. A deep, upper-level trough over the western U.S. continues to bring unsettled weather and cool conditions to portions of the West. Ongoing showers and some thunderstorms as well as higher elevation snow across the Sierra Nevada and central Great Basin should begin to taper off through tonight and into the early morning hours Monday. Some snow may mix in with the showers at lower elevations, though accumulations are not expected. Further east, moist, southerly return flow across the Plains as well as increasing upper-level support as the upper-trough begins to overspread the region will bring the risk of some isolated afternoon thunderstorms today along the High Plains. Strong CAPE supported by the boundary layer moisture as well as sufficient upper- and low-level shear given strong wind fields with the approaching trough will bring the threat of some severe weather. A Slight Risk (level 2/5) has been issued by the Storm Prediction Center for the chance of very large hail, damaging winds, and a few tornadoes. More widespread storms along portions of the northern High Plains of Montana have prompted a Slight Risk of Excessive Rainfall (level 2/4) as locally heavy rainfall rates supported by the very moist, upslope flow in combination with snowmelt over terrain sensitive areas, including burn scars, may lead to some scattered instances of flash flooding. Additional, more isolated instances of flash flooding will be possible as storms over the northern High Plains grow upscale into a complex and move eastward through the Dakotas during the overnight hours. The potent upslope flow will bring heavy snow to higher mountain elevations of southern Montana and northern Wyoming, with winter weather-related advisories in place for some significant accumulations as much as 1-3 feet. Then, on Monday, as the upper-level trough shifts further eastward across the Plains and over portions of the Midwest, another day of moist return flow as well as the very strong wind fields will support the development of widespread, intense thunderstorms and a potentially significant severe weather outbreak. The Storm Prediction Center has issued a Moderate Risk (level 4/5) over portions of the Upper Mississippi Valley as supercells possible ahead of an approaching cold front will be capable of producing strong tornadoes, very large hail, and damaging winds. An Enhanced Risk (level 3/5) extends southwestward along the cold front through the Middle Missouri Valley with a Slight Risk southwestward through the southern Plains as additional storms along the cold front will bring an increasingly more isolated but still notable threat for very large hail, damaging winds, and a few tornadoes. Locally heavy rainfall may also lead to some isolated instances of flash flooding as well. On Tuesday, the cold front will begin to slow and stall with southwestward extend over the southern Plains as leading upper-level energy quickly lifts northeastward. Repetitive rounds of storms in vicinity of the stalling boundary over an already sensitive region given recent rainfall has resulted in a Moderate Risk of Excessive Rainfall (level 3/4) for portions of southwest Oklahoma and northwest Texas with scattered to numerous instances of flash flooding possible. A broader Slight Risk extends northeastward towards the Middle Mississippi Valley and southwestward into the Texas Big Country for additional scattered instances of flash flooding. More generally, scattered to widespread storms are expected along the cold front from the interior Northeast southwestward through the Ohio/Middle Mississippi Valley and southern Plains. The Storm Prediction Center has included a Slight Risk of severe weather along the length of the front as some storms will be capable of large hail and damaging winds. Elsewhere, very dry conditions as well strong, gusty winds have prompted an Extremely Critical Risk of fire weather (level 3/3) from the Storm Prediction Center for portions of New Mexico through the rest of today, with Elevated conditions (level 1/3) remaining in place Monday. A quasi-stationary frontal boundary across portions of the Southeast will bring some shower and thunderstorm chances on Monday. A Pacific system will bring increasing precipitation chances to the Pacific Northwest Monday evening and then inland through the northern Great Basin and Rockies into Tuesday. An upper-level ridge building over much of the central/eastern U.S. will bring well above average conditions to start the week. Forecast highs in the 70s and 80s will be common, including for more northern locations like the Midwest and Northeast. After a cool, well below average weekend, temperatures will begin to return back closer to average over the West Monday and especially into Tuesday, with highs generally ranging in the 60s and 70s, with 80s into the Desert Southwest. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php