Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 355 PM EDT Mon Jun 24 2024 Valid 00Z Tue Jun 25 2024 - 00Z Thu Jun 27 2024 ...Heat wave focus shifts to the Southeast, Mid-South, and central/southern Plains into midweek... ...Severe storms and flash flooding possible for portions of the Upper Midwest into Monday night, shifting a bit south Tuesday... ...Monsoon-like conditions persist for the Southwest/Four Corners Region... A broad upper-level ridge building over the west-central U.S. will continue to produce potentially hazardous heat over the next few days. Forecast high temperatures will continue to soar into the upper 90s across much of the Plains and Mississippi Valley and into southeastern parts of the Lower 48, with low 100s possible over the central Plains. When combined with the humidity, heat index values may reach as high as 110, prompting Heat Advisories and some embedded Excessive Heat Warnings. Meanwhile, low temperatures will mostly remain in the mid- to upper 70s, bringing little relief from the heat overnight. The arrival of this more intense heat early in the Summer season leads to a higher level of heat-related stress, especially for those outdoors and without reliable air conditioning available. While the north-central U.S. can expect some relief from the heat Tuesday and especially Wednesday behind a cold front, the Southern Plains to Mid-South to Southeast will maintain potentially dangerously hot conditions through the period, with a brief period of heat returning to the Middle Mississippi/Ohio Valleys on Tuesday and Mid-Atlantic on Wednesday. To the north, an upper-level shortwave and accompanying surface frontal system will move along the northern tier of the central U.S. towards the Upper Midwest. Deep moisture flowing northward ahead of the system will bring increasing storm chances through tonight. Hot temperatures along with the plentiful moisture will lead to strong to extreme instability, prompting an Enhanced Risk of severe weather (level 3/5) from the Storm Prediction Center. Tornadoes and large hail are possible with the storms, but the primary threat is a corridor of very high wind across southern Wisconsin and surrounding states. Additionally, a Marginal to Slight Risk of excessive rainfall causing flash flooding is in place for portions of the Upper Midwest with locally heavy downpours. The low system will continue eastward on Tuesday, with a cold front pushing southeastward into the Midwest/Great Lakes region. Storms developing along and ahead of the front could tend to repeat over the same areas as storm motions become more parallel to the increasingly east-to-westward oriented front. This is prompting a larger Slight Risk of flash flooding for portions of the Middle Mississippi Valley with a Slight Risk of severe weather aligned in a similar area for Tuesday into Tuesday night. By Wednesday, the southeastward progression of the front will produce thunderstorm chances from the Lower/Middle Mississippi Valley into the Tennessee and Ohio Valley to the Mid-Atlantic and Northeast. Daily shower and thunderstorm chances continue over portions of the Southwest/Four Corners Region as an influx of ample tropical moisture brings monsoon-like conditions. Some locally intense downpours are possible and may lead to isolated instances of flash flooding, for broad Marginal Risks in the Excessive Rainfall Outlook (ERO). Through Monday evening, more focused rainfall may be possible in southeast Arizona, which may cause more scattered instances of flash flooding especially for urban areas around Tuscon. Then by Wednesday, rainfall may be particularly concerning over portions of New Mexico that are sensitive to additional rainfall due to recent burn scars, prompting an embedded Slight Risk there in the Day 3 ERO. The higher moisture, cloud cover, and storms will keep temperatures around average, with 80s and 90s in the Four Corners region and 100s to 110 for the Southwest. Forecast high temperatures are generally above average by 5-10 degrees elsewhere in the West, with 60s and 70s along the immediate Pacific Coast, 70s and 80s in the Pacific Northwest, and low to mid-90s for the Great Basin. Highs in the low to mid-100s for portions of interior central California and the 110s for the western Mojave/Sonoran Deserts have prompted heat-related advisories and warnings. Elsewhere, areas of showers and storms may continue into this evening/tonight in the vicinity of a surface low slowly pushing away from northern New England. Farther south, additional storms are possible ahead of a cold front over portions of the Southeast. Diurnal sea breeze-related storms are also expected over Florida Monday and Tuesday. Welcome relief from the weekend's heat is present in the Mid-Atlantic, with highs generally in the 70s and 80s. Temperatures will gradually rise across the Eastern Seaboard Tuesday and Wednesday, with highs in the upper 80s to 90s. Tate/Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php