Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Thu Aug 29 2024 Valid 12Z Thu Aug 29 2024 - 12Z Sat Aug 31 2024 ...Above average heat expected to linger across the Ohio and Tennessee Valleys through Friday before a cooling trend arrives by the weekend... ...Strong to severe thunderstorms expected across the upper Midwest and Mid-Atlantic today, then across the Great Lakes on Friday... ...Some tropical heavy rain and thunderstorms could affect the western Gulf Coast region through the next couple of days... A vigorous low pressure system currently centered near the U.S.-Canadian border of the High Plains will move steadily across southern Canada through the next couple of days. Strong to severe thunderstorms forming ahead of a potent cold front trailing south from the low pressure center will likely impact North Dakota early this morning, before quickly advancing into Minnesota and down across the central Plains into this evening. These thunderstorms could develop into supercells that may contain damaging winds, large hail, and a few tornadoes. Meanwhile, thunderstorms across the Mid-Atlantic could also be strong to severe where some gusty winds and heavy rain may lead to isolated to scattered instances of flash flooding by this evening and into the overnight. The front that helps trigger these thunderstorms will gradually edge farther southward into the Mid-Atlantic on Friday, bringing relief from the heat with high temperatures only reaching into the 70s for much of the Northeast. The cool air will not have a chance to reach into the Ohio and Tennessee Valleys though as southerly flow increases ahead of the deep low pressure system in southern Canada. A couple more days of heat with afternoon high temperatures well up into the 90s are expected in these areas. Above average overnight low temperatures will provide little relief, lows will likely stay in the 70s for much of the region. A cooling trend will set in by the weekend behind the cold front. Scattered thunderstorms with embedded strong to severe storms will then extend southwestward across the Midwest into the central Plains on Friday as the trailing end of the front begins to slow down and become nearly stationary into the southern Plains by Saturday. Separate from the frontal system across the northern tier of the country, tropical moisture from the Gulf of Mexico could lead to heavy rain across portions of the western Gulf Coast region as an upper-level low lingers over Texas. A small scale low pressure center could form and interact with a subtle coastal front to enhance rainfall rates, leading to the potential for flooding issues over portions of the the western Gulf Coast through the next couple of days. Across the rest of the country, a general cooldown is expected behind the cold front across the north-central U.S. and high temperatures should be generally in the middle 80s. Much of the Southeast should be warm and humid with commonplace high temperatures in the middle 90s. A warming trend is expected for the western U.S. following the recent cool spell as the strong low departs into southern Canada. Kong/Wilder Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php