Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 313 PM EDT Sat Jun 29 2024 Valid 00Z Sun Jun 30 2024 - 00Z Tue Jul 02 2024 ...Severe thunderstorm and heavy rain threat for the East Coast on Sunday... ...Showers and thunderstorms for the Four Corners/Southwest over the next few days; wet weather returns to the upper Midwest by Monday... ...Dangerously hot conditions will continue for the Southeast this weekend... A cold front moving through the Great Lakes this evening will bring in cooler and drier air to the region for Sunday, with showers and thunderstorms out ahead of it over much of the Northeast, Ohio Valley, and Mid-Atlantic. By Sunday, the front will push closer to the I-95 corridor, focusing the chance for thunderstorms (some severe per the Storm Prediction Center) toward the coast in the Northeast, but also into the Mid-Atlantic and central/southern Appalachians. Isolated flash flooding is possible in some areas that experience heavier rainfall in a short amount of time. Farther south, the frontal boundary will slip into the Mid-South and TN Valley, with scattered showers and thunderstorms on Sunday. Farther west, tail-end of the same frontal boundary will help fire off mainly afternoon showers and storms over the Four Corners region and across much of the Rockies. Flash flooding is possible in some areas, especially in more sensitive regions with steep terrain. Over the northern Rockies, a system will bring an expanding area of rain and thunderstorms tonight into Sunday, moving into eastern Montana where some severe weather is possible. By late Sunday into Monday, potentially heavier rainfall will push into the Upper Midwest/Corn Belt where Flash Flooding will be possible over areas that have seen well above normal rainfall recently. Isolated flash, urban, and small stream flooding along with new and renewed river rises are possible per the National Water Center. Temperatures will be quite variable across the Lower 48 over the next two days. Much of the northern tier -- from the northern Plains eastward to the Great Lakes -- will see below normal temperatures on Sunday into Monday with highs generally only in the 70s. Ahead of the front to the east, warm/hot temperatures in the 80s/90s on Sunday near the East Coast will be replaced by 70s/80s on Monday. The hottest temperatures will be located over much of the southern Plains to the Southeast, as well as into the Desert Southwest. Though daytime maximum temperatures may not break daily records, overnight low temperatures will remain quite warm (only in the 70s to around 80 degrees) due to high levels of humidity. This will be reflected during the day by high heat indices in the low 100s. By Monday, much of interior California will start to see temperatures near and over 100 degrees, as will parts of the central Plains. Fracasso Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php