Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Wed Aug 28 2024 Valid 12Z Wed Aug 28 2024 - 12Z Fri Aug 30 2024 ...Record heat for the Mid-Atlantic today but the heat will last a couple more days for the Ohio and Tennessee Valleys into the interior Southeast... ...Active thunderstorms will bring the threats of heavy rain, flash flooding and severe weather across the northern Plains tonight and then the upper Midwest Thursday through early Friday... ...Strong to severe late afternoon thunderstorms possible across the east-central U.S for today and Thursday... ...First snowflakes of the season expected for the high elevations of northwestern Montana today while fire weather threat blankets portions of the northern Rockies... A cold front has brought relief to the heat across the northern Plains while triggering clusters of strong thunderstorms across the Midwest this morning. As the front continues to push east and southeastward, a day of record heat is expected to impact the Mid-Atlantic states where high temperature could reach 100 degrees around the nation's capital. This heatwave will be relatively short-lived for the Mid-Atlantic as a much cooler and damp air mass associated with a Canadian high pressure system will quickly settle southward across the Great Lakes/New England into the Mid-Atlantic by Thursday. However, much of the Ohio and Tennessee Valleys will feel a couple more days of high temperatures topping into the upper 90s at the hottest locations as the next low pressure system marching across the northern Plains will cease the southward progress of the cool air and keep the heat in place for these areas. As the cold front approaches, the hot air will be lifted and help trigger lines of thunderstorms which can become severe along with locally heavy downpours and very gusty winds. The highest threat for severe weather will be later today into this evening from Ohio eastward across the northern Mid-Atlantic near/after the time of maximum heating in the afternoon. Some more strong thunderstorms could form Thursday afternoon farther southward into the Mid-Atlantic on Thursday. Very cool air will then blanket the entire Northeast on Thursday. Meanwhile, the strong cold front associated with the next low pressure system is marching across the northern Rockies. Sharply colder air behind the system will likely bring the first snowflakes of the season for the high elevations of northwestern Montana today while fire weather threat blankets portions of the northern Rockies. The strong frontal system will move steadily across the northern and central Plains on Thursday where the threat of severe weather will be highest from Wednesday night across North Dakota, then shifting east across a large chunk of the Midwest and upper Midwest Thursday to Thursday night. Farther south in Texas, an upper low had moved inland from the Gulf of Mexico since yesterday. The instability has continued to help trigger scattered thunderstorms across southern Texas. Meanwhile, deep southerly flow to the east of the upper low has directed tropical moisture northward from the Gulf toward the western Gulf Coast region, where some heavy rainfall could develop in the vicinity during the next couple of days. Elsewhere, while monsoonal moisture has become not as active and widespread over the southern Rockies today, more focused activities across southwestern New Mexico could lead to heavy rainfall. By Thursday, the trailing cold front across the Plains will likely push the rain farther east into the southern Plains where strong to severe storms are possible by later in the day. Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php