The nation's weather

AP News
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Posted: Mar 21, 2012 5:56 AM
The nation's weather

Weather Underground Forecast for Wednesday, March 21, 2012.

Severe weather moves through the Lower Mississippi River Valley on Wednesday, while wet and snowy weather persists over the Northwest.

A strong low pressure system cover the Southern US continues pushing a cold front eastward throughout the day. Flow around this low pressure system pulls warm and moist air in from the Gulf of Mexico and triggers more heavy rain and severe thunderstorms across the Lower Mississippi River Valley and Southeast. This system will continue causing major flooding problems as it moves eastward throughout the day. Rainfall totals are likely to surpass 3 inches in some areas. Flood advisories have been issued from the Mid-Mississippi River Valley through the Gulf coast. There is a a slight chance that severe thunderstorms will develop over the Southeast on Wednesday. If storms turn severe, expect strong winds, large hail, and possibly a few tornadoes. After the cold front passes, slight cooler temperatures are anticipated. Expect highs to range in the 60s and 70s across the Central US.

Meanwhile ahead of this cold front, unseasonably warm temperatures persist across the Eastern US. High temperatures will reach into the 80s across the Ohio River Valley, Midwest, and Eastern Valleys.

In the West, a low pressure system in the Pacific Ocean continues pushing a cold front onshore. This pulls additional moisture in, allowing for rain and high elevation snow showers to persist across the Pacific Northwest and Northern Rockies. Snowfall accumulations will range between 3 to 5 inches across most of the region. Temperatures in the Lower 48 states Tuesday have ranged from a morning low of 3 degrees at Monarch Pass, Colo. to a high of 87 degrees at Middlesboro, Ky.