Severe Weather and Excessive Rainfall Threats Over the Central U.S. Into Early Next Week
Sweltering Heat Continues Across South Florida and Southern Texas While Expanding Into the Southern High Plains
An energetic upper-level pattern is expected to bring multiple rounds of storms to the central U.S. on Sunday and Monday. On Sunday, moist return flow following a warm front moving northward through the Plains and ahead of a dryline over the High Plains will create significant instability, triggering robust thunderstorm development in the Central Plains. Increasing upper-level winds will promote supercells with threats of large hail and a few tornadoes. These storms are anticipated to evolve into organized convective systems, leading to a heightened risk of widespread, significant damaging winds later Sunday evening. Consequently, the Storm Prediction Center has issued a Moderate Risk of severe weather (level 4/5). The storm threat will shift northeast into the Upper Midwest overnight Sunday and into the Great Lakes by Monday, following an initial upper-wave and accompanying surface frontal system. An amplifying long-wave trough over the West will enhance lee cyclogenesis over the High Plains, bringing another chance of storms to the Central Plains/Missouri Valley by Monday evening. The Storm Prediction Center has included a Slight Risk (level 2/5) for damaging winds, large hail, and possibly a tornado. Locally heavy downpours and isolated flash flooding are possible, particularly from the Central Plains to the Upper Mississippi Valley on Sunday and the Central Plains again on Monday.
The active upper-level pattern will also bring some precipitation to the Northern/Central Rockies and eastern Great Basin over the next few days. Rainfall is expected to be light to moderate, though some locally heavier storms are possible, especially over Wyoming on Monday. Higher mountain elevations may see some snow. To the east, a low-pressure area off the Atlantic coast of the Southeast, along with a trailing frontal boundary moving through Florida, will bring more showers and thunderstorms on Sunday. Storm chances will decrease overnight Sunday and into Monday as the front moves southward, clearing the coast by Tuesday morning.
Intense summer-like heat will persist in parts of South Florida and from southern Texas into the southern High Plains over the next few days. High temperatures in the 90s, combined with high humidity, will push heat indices into the 105-110 degree range, with a Heat Advisory in effect for South Florida on Sunday. While not as humid, temperatures in the 100s are expected further inland in west Texas and the southern High Plains, with some record-tying or breaking temperatures possible. Elsewhere across the central and eastern U.S., temperatures will remain well above average, with highs in the 80s even in northern areas like the Great Lakes and the interior Northeast. Onshore flow will keep coastal regions cooler, with highs in the 60s and 70s from coastal New England to the Mid-Atlantic and coastal Carolinas. The Pacific Northwest and northern Rockies will experience cooler temperatures on Sunday behind a cold front, with highs in the 50s and 60s. These cooler temperatures will spread southward into the Great Basin by Monday, while highs in the 80s and 90s are forecast for the Southwest.