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 , 10:13 PM GMT on August 29, 2014
Weather Underground Forecast for Saturday, August 30, 2014
A low pressure system will move across the upper Mississippi Valley on Saturday, while a separate low pressure system will dip southward over southern Canada.
An area of low pressure will dip southward over south central Canada and the upper Intermountain West on Saturday. As warm, humid air interacts with this system, strong to severe thunderstorms will develop over the north central portion of the country. Severe thunderstorms will be possible over northeast Montana, northwest South Dakota and western North Dakota. These thunderstorms will be capable of producing large hail, dangerous straight line winds and isolated tornadoes. Scattered thunderstorms will also be possible over the northern and central Rockies. An onshore flow from the Pacific will bring a chance of showers to the Pacific Northwest, while high pressure will keep the remainder of the West Coast clear of precipitation.
Meanwhile, a strong low pressure system will drift northeastward over the upper Mississippi Valley and the western Great Lakes on Saturday. Widespread rain and thunderstorms are expected over the middle and upper Mississippi Valley, as well as the upper Midwest and the Tennessee Valley. To the south, a tropical disturbance over the western Gulf of Mexico will bring heavy rain and thunderstorms to the western and central Gulf Coast. Isolated thunderstorms are also forecast to develop over Florida and the southern Mid-Atlantic. The Northeast will stay mostly clear of wet weather.
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