A front that persisted from the Mid-Atlantic to the Southern Plains was forecast to gradually shift to the Southeast on Wednesday.
Showers and thunderstorms were expected to continue along the frontal boundary. Heavier precipitation amounts and rates were expected in Virginia, the Carolinas, central Texas and southern Louisiana. Some afternoon scattered showers and isolated thunderstorms were expected in southern Florida.
Farther north, a low pressure system in southern Ontario was expected to drop into the Upper Midwest and Great Lakes region, producing light to moderate rain. By Thursday morning, precipitation should spread across the Northeast and parts of the Ohio Valley. Rain may mix with snow showers in eastern shores of Lake Erie and Lake Ontario, northeastern Ohio, northwestern Pennsylvania and far western New York State. Apart from the precipitation, this system would also usher much colder airmass into the Midwest and Northeast.
Moving to the West, the low pressure system off northern Baja California was forecast to slowly drift eastward, resulting in continued showers and thunderstorms across the southwestern U.S. into Thursday. Forecasters said some heavier rainfall may occur in the western and southern slopes of the mountains or higher terrain. On the other hand, a ridge of high pressure was expected to keep much of the Northwest and northern California warm and dry.
Temperatures in the Lower 48 states Tuesday ranged from a low of 16 degrees at Bear Lake Airport in Idaho to a high of 93 degrees at Laredo, Texas.