Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 311 PM EDT Wed Jul 24 2024 Valid 00Z Thu Jul 25 2024 - 00Z Sat Jul 27 2024 ...Major to locally extreme Heat Risk will expand across the northern High Plains as heat gradually becomes less intense over the Central Valley of California and the Great Basin... ...Excessive Rainfall probable along the Texas coast through Thursday while scattered showers and thunderstorms extend across the southern tier states to the East Coast... ...Scattered to Severe Thunderstorms possible across portions of the Northern Appalachians/interior Northeast tonight... ...Monsoonal thunderstorms continue across the Great Basin and into the Four Corners region with threats of localized flash flooding; fire weather danger emerges over the interior Northwest... A slow-to-evolve summertime weather pattern will continue across much of the U.S. mainland while a more progressive Pacific cold front sweeps across the northwestern part of the country through the next couple of days. Under this weather pattern, unsettled weather and relatively cool temperatures for July will continue across the eastern half of the country as the ongoing heat wave over the western U.S. gradually becomes less intense with the arrival of the Pacific cold front. The stronger forcing associated with this front will push the heat dome east of the Great Basin, resulting in the expansion of major to locally extreme Heat Risk across the northern High Plains over the next couple of days. High temperatures are forecast to reach well up into the 100s to near 110 at the hottest location over the northern High Plains through Thursday with little to no rainfall expected. Meanwhile, the heat will gradually become less intense over the Central Valley of California and the Great Basin with time. Please continue to practice heat safety as the heat spreads into the northern High Plains. By Thursday night into Friday morning, the cold front will make its way through the northern Rockies into the High Plains with cooler air arriving but with very little moisture to work with. Meanwhile, lightning associated with dry thunderstorms triggered by the passage of the cold front will result in critical fire danger over the interior northwestern U.S. In addition, monsoonal thunderstorms will continue across the Great Basin/southern Sierra Nevada tonight and become more numerous over the Four Corners region Thursday into Friday with the threat of localized flash flooding over the next couple of days. The Storm Prediction Center issued a Slight Risk of Severe Thunderstorms over portions of southern Arizona this afternoon/evening due to storm development along the Mogollon Rim and southeastern AZ mountains, which are expected to propagate southward into the lower desert and cause damaging wind gusts and substantial blowing dust. In contrast to the heat in the West, cooler than normal temperatures will prevail across the mid-section of the country to portions of the eastern U.S. where a stalled front will keep plenty of clouds along with scattered thunderstorms. Some scattered thunderstorms this afternoon may develop into severe storms by this evening across portions of northwestern Pennsylvania into central to eastern upstate New York. Thunderstorms are not expected to be severe, but they could result in localized flooding issues from time to time across the southern tier states as well as up and down the East Coast. There's a persistent Slight Risk of Excessive Rainfall in effect over portions of the Carolinas through Friday where storms are expected to continue reoccurring. A coastal front interacting with a broad upper-level southwesterly flow could set off heavy rain and thunderstorms near the Texas coast into southwestern Louisiana where flash flooding is probable. A Moderate Risk of Excessive Rainfall leading to Flash Flooding is in effect from Texas' eastern Gulf Coast into Louisiana's western coast tonight and then expanding in coverage into Texas' central Gulf Coast on Thursday. Elsewhere, some scattered thunderstorm activity is possible across portions of northern Maine late Thursday afternoon. Kebede/Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php