The Nation's Weather 10.23.09

By WEATHER UNDERGROUND (AP)

The Eastern U.S. was forecast to continue seeing wet weather Friday with periods of heavy rainfall in the South, and light snowfall in the North.

A strong low pressure system would continue tracking eastward through the country and move into the Great Lakes. The system was expected to push a cold front over the Mississippi and up the Ohio River Valley. This was expected to trigger about a half of inch of rain over the Ohio and Tennessee Valleys, while moisture from the Gulf of Mexico might allow for heavier showers associated with scattered thunderstorm development.

These storms were not expected to turn severe with rainfall ranging around an inch. The Great Lakes region was also forecast to see up to an inch of rainfall as temperatures remain above freezing on Friday. This system would also allow for flooding to remain a threat over most of the Mississippi.

However, behind this system, extremely cool temperatures would continue over the Plains as cold air poured in from Canada, some areas would experience up to 30 degrees cooler than usual October conditions. With lingering moisture over the region, this would allow for scattered snow showers over the Northern and Central Plains. The Southern Plains would remain dry and sunny, but high temperatures would remain roughly 10-15 degrees cooler and seasonable.
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In the West, another trough of low pressure was expected to move onshore from the Pacific and trigger light showers over the Pacific Northwest. Moisture from this system was expected to spread clouds down the West Coast, but precipitation was not expected.

Temperatures in the Lower 48 states Thursday ranged from a low of 14 degrees at Shirley Basin, Wyo., to a high of 94 degrees at Santa Ana, Calif.