Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 332 AM EDT Sat May 29 2021 Valid 12Z Sat May 29 2021 - 12Z Mon May 31 2021 ...Additional rounds of severe weather and flash flooding possible across the central and southern Plains through the weekend... ...Below average temperatures found throughout much of the central and eastern United States, while heat builds in the West... Unsettled weather will be found across parts of the central and southern Plains, as well as the East Coast this holiday weekend. The most hazardous conditions are expected in the Great Plains as additional rounds of thunderstorms stretch from eastern Colorado to West Texas through Memorial Day. The threat of damaging wind gusts, large hail, and isolated tornadoes exists today throughout the central High Plains and shifts southward into southeast New Mexico and southwestern Texas on Sunday. Scattered instances of flash flooding are also possible with the thunderstorm activity as high rainfall rates lead to multiple inches of rain falling in a relatively short period of time. WPC has issued a Slight Risk of Excessive Rainfall for today across the central High Plains, with a Slight Risk also issued for Sunday over parts of the Southern Plains and far south-central Kansas. Meanwhile, damp and dreary weather will be found across much of the Mid-Atlantic and Northeast through early Monday as a frontal boundary stalls along the East Coast. Showers and locally heavy rain will make it difficult to stay dry if spending time outdoors, with a stiff northeast wind making conditions feel even more uncomfortable. These gusty winds may also lead to coastal flooding from Long Island to the Delmarva Peninsula. Coastal Flood Watches and Advisories are in effect. A low pressure system is forecast to eventually develop along the aforementioned frontal boundary and swing into New England on Monday, subsequently leading to much of the Mid-Atlantic enjoying a drier and pleasant Memorial Day. May is forecast to end quite chilly throughout the central and eastern United States, with high temperatures only reaching the 50s and 60s from the central Plains, Midwest, and Ohio Valley to the Mid-Atlantic and Northeast. On the northern side of the cold airmass, early morning temperatures will dip low enough for freeze and frost concerns in the Upper Midwest and Great Lakes this morning. The opposite is expected in the western U.S. as heat begins to slowly build into the region. Excessive Heat Warnings and Heat Advisories have already been issued across the Sacramento Valley and northern San Joaquin Valley for Sunday and Monday. Highs are forecast to reach the upper-90s and triple digits on Sunday throughout much of the Desert Southwest and California's Central Valley. Snell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php