A very large storm will move out of the Rockies and into the Plains, the most active weather system in the country Sunday. The particularly large storm will spread from the northern Plains through the central Rockies and into the upper Midwest.

While the spring storm will initially lack the moisture coming up from the Gulf of Mexico, it will begin to produce strong thunderstorms from Texas through Illinois as it moves eastward later in the day and on Monday. These thunderstorms will have the potential of turning severe, with damaging wind, hail, and even possibly tornadoes.

Residents in the Southeast should monitor weather conditions due to approaching severe weather.

Closer to the storm's center, widespread rain is likely in the Dakotas and Minnesota. This rainfall will hasten the annual snowmelt that is expected to keep flooding conditions likely throughout the spring in the Missouri and Mississippi Rivers.

Rain will gradually increase in New England later Sunday afternoon and evening.

Cool, but dry, conditions are expected in California and much of the Southwest.

The Northeast's temperatures will reach the 50s and 60s, while the Southeast will see readings in the 80s and 90s. The Southern Plains will rise into the 80s and 90s, while the Northern Plains will see temperatures in the 40s, 50s, and 60s. The Northwest will rise into the 40s, 50s, and some 60s. Temperatures in the lower 48 states ranged Saturday from a morning low of 5 degrees at St. George, Utah, to a high of 97 degrees at Laredo, Texas.