Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EDT Wed May 26 2021 Valid 00Z Thu May 27 2021 - 00Z Sat May 29 2021 ...Moderate and Enhanced risk of strong to severe thunderstorms over portions of the central US Thursday and Friday, respectively... ...Showers and potentially severe thunderstorms continue in the Northeast before being ushered offshore overnight by a passing cold front... ...Cold spell in store for the northern Great Plains, Midwest, and Northeast Thursday into Friday... Throughout the Great Plains showers and thunderstorms will continue overnight and spread eastward as a low pressure system moves across the central US, deepening along its path. It is expected that several of these thunderstorms will become severe, bringing with them intense damaging winds, very large hail, and potentially strong tornadoes. At present, the Storm Prediction Center has issued a moderate risk of severe weather for portions of Nebraska and Kansas. In addition to the severe weather threat, heavy downpours from thunderstorms could result in flash flooding. The Weather Prediction Center has issued a slight risk of excessive rainfall for portions of the central Plains through Thursday morning. As the system progresses east, so will the areas of concern for severe weather and flash flooding. For Thursday, the Storm Prediction Center has issued an enhanced risk of severe thunderstorms across parts of the southern and central Plains and the Middle Mississippi Valley, where very large hail, significant severe wind gusts, and the potential for several tornadoes to develop will be the hazards of concern. The Weather Prediction Center has flagged a similar area as being at slight risk for excessive rainfall and flash flooding. Having been pushed south and east by a descending area of high pressure, showers and thunderstorms are expected along the Gulf and East Coasts on Friday. A strong cold front trailing off a deep Canadian low pressure system will pass through the Northeast overnight. Ahead of the front warm temperatures and shortwave instability are expected to aid the development of showers and thunderstorms, some of which may become severe and produce damaging winds. Behind the cold front a high pressure system in southern Canada is forecast to build and spread east, transporting colder arctic air south into the northern Great Plains, Midwest, and Northeast. On Thursday and Friday, daily highs across these regions will likely drop as much as 15 to 20 degrees below normal into the 50s and 60s. Out in the Pacific Northwest, a low pressure system moving onshore Thursday morning will bring widespread rain to the area, with mixed precipitation and even some wet snow possible in the northern Cascades. As the system moves inland the rain is forecast to expand eastward into the northern Rockies, some of which may transition into wet snow at higher elevations overnight as temperatures drop behind a cold front. The northern Cascades could see wet snow lingering into Friday morning as well. Zavadoff Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php