Expect more scattered storms across the plains on Sunday, while heavy rains over Florida slightly advance up the East Coast. An area of low pressure over Florida and the Bahamas produces organized showers and thunderstorms that create intense downpours and strong winds. Thus, the system has been placed under a moderate chance of tropical cyclone development.
On Sunday, the system will start to move northward up the Southeastern coast and into the southern Mid-Atlantic states. The system will remain strong as it continues pulling moisture and energy off the Atlantic Ocean. Expect heavy rains, strong winds, and dangerous surf from Florida to the Carolinas. Rainfall totals between 3 to 4 inches are likely, up to 6 inches possible in areas of severe thunderstorm development.
Meanwhile, high pressure lingering over the Great Lakes, Northeast and Mississippi River Valley will produce another warm and sunny fall day. Expect high temperatures to remain in the 70s and 80s, or about 15 to 20 degrees above seasonable.
A strong frontal boundary will remain stationary over the Plains, stretching from the Dakotas and Upper Midwest into Texas. Flow on the eastern edge of this system will pull warm and moist air in from the Gulf of Mexico, feeding the system for more thunderstorm development. Some of these storms will turn severe with strong winds, large hail and periods of heavy rains.
Behind this system, cool air will pour in from Canada, bringing chilly conditions to the northern Rockies, Intermountain West and Great Basin. Expect temperatures to range from 10 to 15 degrees below seasonable, while overnight lows will dip into the 30s. Thus, freeze and frost advisories have been issued across these areas.