Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon Jun 24 2024 Valid 12Z Mon Jun 24 2024 - 12Z Wed Jun 26 2024 ...Heat wave focus shifts to the Southeast, Mid-South, and central/southern Plains early this week... ...Severe storms for portions of the Upper Midwest on Monday, with an increasing flash flooding threat for the Midwest Tuesday... ...Monsoon-like conditions persist for the Southwest/Four Corners Region... As an upper-level trough moves over the northeastern U.S., bringing relief from the heat over the weekend, a broad upper-level ridge will build over the central/western U.S., shifting the focus for the ongoing heat wave to the Southeast, Mid-South, and central/southern Plains early this week. Forecast high temperatures will continue to soar into the upper 90s over the region, with low 100s possible over the central Plains. When combined with the humidity, heat index values may reach as high as 110, prompting widespread Heat Advisories. 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. 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 during the day Monday. Deep moisture flowing northward ahead of the system will bring increasing storm chances by later Monday afternoon and into Monday evening. Hot temperatures along with the plentiful moisture will lead to strong to extreme instability, prompting a Slight Risk of severe weather (level 2/5) from the Storm Prediction Center. Very large hail and significant damaging winds can be expected with any storms, and possibly a tornado. A potentially higher threat of damaging winds exists if enough storms develop and evolve into an organized convective system. Locally heavy downpours can also be expected, with an isolated risk of flash flooding especially if storms are able to become more organized and widespread. The 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 will tend to repeat over the same areas as storm motions become more parallel to the increasingly east-to-westward oriented front. This will bring a greater chance of flash flooding compared to Monday, with a Slight Risk of Excessive Rainfall (level 2/4) in effect. Some severe storms will again be possible, with a Slight Risk in place for the threat of large hail and damaging winds. Daily shower and thunderstorm chances continue over portions of the Southwest/Four Corners Region as an influx of tropical moisture brings Monsoon-like conditions. Some locally intense downpours are possible and may lead to isolated instances of flash flooding. The highest confidence in storm coverage exists over portions of southeast Arizona where a Slight Risk of Excessive Rainfall is in effect. A few more scattered instances of flash flooding will be possible here, especially for urban areas around Tuscon. 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 will continue in the vicinity of a surface low and cold front pushing through Upstate New York and New England into early Monday afternoon. Storm chances should taper off as the system clears the coast Monday evening. Further south, additional storms will be 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 heat will come to the Mid-Atlantic, with highs generally in the 70s and 80s. Temperatures will return closer to average Tuesday, with highs in the upper 80s to low 90s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php