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The nation's weather

[July 20, 2009] (AP) Several disturbances were expected to trigger active weather across the nation on Monday.

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In the central U.S., a trough of low pressure over southern Canada was forecast to dig southward into the northern Plains, supporting a cold front moving through the northern and central Plains. As this disturbance advances eastward, scattered precipitation and thunderstorms were expected to develop from the Plains to the upper Mississippi Valley. Afternoon heating was likely to enhance instability in the central and southern Plains and was forecast to yield to some severe weather development. Strong to damaging northwesterly winds were expected to accompany thunderstorms throughout these regions.

In the East, forecasters were calling for another frontal boundary to lift northward and become positioned from the Mid-Atlantic Coast through the Southeast. As this system climbs to the north, increasing amounts of moisture from the Gulf of Mexico were expected to spread throughout these southern regions, creating a chance for showers and strong to severe thunderstorms throughout the day. Meanwhile, pockets of showers may pop up across the Ohio Valley and Great Lakes due to a weak wave of low pressure.

In the West, hot and mostly dry weather was expected to persist as high pressure builds over the Great Basin. Moist, onshore flow was forecast to keep areas along the coast cool and may spark a few mountain storms as it lifts across the higher elevations.

Temperatures in the Lower 48 states Sunday ranged from a low of 33 degrees at Embarrass, Minn., to a high of 126 degrees at Death Valley, Calif.

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On the Net:

Weather Underground: http://www.wunderground.com/

National Weather Service:
http://iwin.nws.noaa.gov/

Intellicast:
http://www.intellicast.com/

[Associated Press article from Weather Underground]