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 21, 2014
Weather Underground Forecast for Friday, August 22, 2014
A cold front will extend across the upper Intermountain West and the northern Plains on Friday, while a separate frontal boundary will stretch from the upper Midwest to the Mid-Atlantic.
A cold front will dip southward over the Intermountain West and the northern Plains. As this frontal boundary interacts with monsoonal moisture, showers and thunderstorms will develop over the upper Intermountain West, the northern Plains and the central Plains. Heavy rain associated with these thunderstorms will bring a chance of flash flooding to Montana. Just to the south, scattered showers and thunderstorms will develop over the Four Corners as monsoonal moisture surges across the region. The majority of the West Coast will stay clear of wet weather due to a ridge of high pressure over the eastern Pacific.
A separate frontal boundary will extend across the upper Midwest, the Ohio Valley, the central Appalachians and the northern Mid-Atlantic. Warm, muggy air from the Gulf of Mexico will collide with this frontal boundary to initiate heavy rain and thunderstorms over the region. Heavy rain could lead to flash flooding over eastern Kentucky, eastern Ohio, West Virginia, southwest Pennsylvania, western Maryland and western Virginia. Rainy weather will also develop over the Northeast.
Meanwhile, an onshore flow from the Gulf of Mexico will continue to trigger isolated thunderstorms across the Gulf Coast and the Southeast. The Deep South and the middle Mississippi Valley will stay mostly clear on Friday.
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