This is the blog for the United States' national forecast. These summaries are by Weather Underground forecasters and are updated twice each day.
By: nationalsummary , 10:11 PM GMT on July 13, 2014
Weather Underground Forecast for Monday, July 14, 2014
A cold frontal boundary will extend from the southern Plains to the Northeast on Monday, while monsoonal thunderstorms will make a return to the Desert Southwest.
A cold front will extend across the southern Plains, the middle Mississippi Valley, the Ohio Valley and the Northeast on Monday. As this cold front overruns a warm, humid air mass, widespread strong to severe thunderstorms will develop across the central and eastern thirds of the country. Severe thunderstorms will be possible across the middle Mississippi Valley and the Ohio Valley. These thunderstorms will be capable of producing large hail, dangerous straight line winds and isolated tornadoes. Strong thunderstorms will also move across the Tennessee Valley, the northern Mid-Atlantic, the eastern Great Lakes and parts of the Northeast.
A separate cold front will extend across the northern Plains and the upper Midwest. Rain and thunderstorms are expected to push across the upper Mississippi Valley and the western Great Lakes. In addition, temperatures are forecast to be 10 to 20 degrees below normal across the northern tier of the country. To the south, sea breeze induced thunderstorms will develop over Florida, while an onshore flow from the Gulf of Mexico will bring scattered thunderstorms to the Gulf Coast.
Monsoonal thunderstorms will make a return to the Intermountain West, the Great Basin and the Desert Southwest on Monday. These thunderstorms will bring a threat of flash flooding to valleys adjacent to sloped terrain. High pressure over the eastern Pacific will keep the majority of the West Coast clear of precipitation.
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