Active weather will persist in North, the Central U.S. will remain hot and muggy, and storms will develop across the Southwest on Tuesday.
Starting in the North, a low pressure system that moved off the Northern Rockies, kicked up scattered showers and thunderstorms over the Northern Plains and Upper Midwest, will continue pushing a warm front eastward. On Tuesday, the warm front will move over the Great Lakes, triggering thunderstorms with periods of severe storms. Large hail, damaging winds and heavy rainfall are likely, but tornadoes are not anticipated. Rainfall totals will range from 1 to 2 inches in most area, up to 3 inches possible in areas of severe storms. Flooding will remain a concern for the Upper Mississippi River Valley and Ohio River Valley. At the same time, the back side of this low pressure system will pull a cold front through the Northern Plains and Upper Midwest, bringing some relief to the heat. These areas will see highs in the lower 80s on Tuesday, whereas the day before they saw highs in the upper 90s.
To the south, a strong ridge of high pressure continues building northeastward from the Southern Plains. As this ridge pushes warm and moist air northward from the Gulf of Mexico, hot and muggy conditions will stretch from the Central and Southern Plains to the Mississippi River Valley. Expect high temperatures ranging from 100 to 110 degrees, with heat index values up to 120 degrees in some areas.
To the West, monsoon moisture lingering over the Southwest produces more scattered showers and thunderstorms from the Four Corners to the Central Rockies. Meanwhile, a trough off the West Coast will allow for temperatures to remain slightly below seasonal across California and the Pacific Northwest.
Temperatures in the Lower 48 states Monday ranged from a morning low of 42 degrees at Arlington, Wash., to a high of 109 degrees at Shawnee, Okla.