Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Sun May 30 2021 Valid 00Z Mon May 31 2021 - 00Z Wed Jun 02 2021 ...Heat wave to expand across the western U.S.... ...Additional rounds of severe weather and flash flooding possible across the central and southern Plains through Tuesday... ...Light to moderate rain and well below-average temperatures to continue across the Northeast into Monday before clearing on Tuesday... As stormy conditions continue across the Plains through midweek, record-breaking heat is expected to build across the West. Meanwhile, drier weather and more seasonal temperatures are forecast to return to most of eastern U.S. by Tuesday. Well-above normal temperatures across the West are expected to increase further on Monday, with triple-digit, record-breaking highs forecast for portions of the central valleys of California on Monday. The heat will build farther north into the Pacific Northwest on Tuesday, and then into the Intermountain West and northern Rockies on Wednesday. On Wednesday, record-breaking temperatures are expected from central California to western Montana. Excessive Heat Warnings are in effect for Monday and Tuesday for the central valleys of California, while heat advisories are in place for a large portion of northern California into southwestern Oregon. An Excessive Heat Watch for Wednesday is now in effect for Death Valley National Park and for portions of southern Nevada. Farther east, showers and thunderstorms will continue to develop this afternoon from the central and southern Rockies into the Plains. Some storms may become strong to severe -- with scattered severe hail and wind, along with a few tornadoes possible across the southern High Plains, especially during the afternoon and evening hours. Heavy rainfall accumulations, resulting in flash flooding are also a concern -- especially across portions of Northwest Texas into the Panhandle region. WPC has upgraded a portion of this region to a Moderate Risk for excessive rainfall on Sunday -- indicating that numerous flash flood are possible. More stormy weather is expected for the central and southern Plains on Monday. However, the threat for severe thunderstorms is forecast to be more confined to parts of southwestern Texas and southeastern New Mexico. Heavy rainfall, leading to localized flooding is expected to be a bigger concern farther to the north across portions of northwestern Texas and western Oklahoma. While continuing across the Plains, showers and thunderstorms will begin to reach farther east into the mid and lower Mississippi Valley on Wednesday. However at this point, the potential for both severe thunderstorms and flooding rains appears to be more limited. Across the northern Plains and Upper Midwest, showers and thunderstorms will likely continue to develop this afternoon, with isolated severe storms possible across northern Minnesota. The threat is forecast to move farther east into central Wisconsin and portions of northern Michigan on Monday. In the East, low pressure moving north along the coast will bring another day of clouds, rain and below-normal temperatures to the Northeast on Monday. Meanwhile, high pressure shifting east from the Ohio Valley will support the return of drier weather and more seasonal temperatures into the Mid Atlantic and Southeast on Monday. By Tuesday, with the low tracking well north into eastern Canada, drier weather and more seasonable temperatures are forecast for much of the eastern U.S. One exception may be central and southern Florida, where a lingering frontal boundary is expected to support showers and thunderstorms through midweek. Pereira Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php