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 23, 2014
Weather Underground Forecast for Sunday, August 24, 2014
A strong low pressure system will move across the northern tier of the country on Sunday, while a cold front will extend from the middle Mississippi Valley to the Southeast.
A strong area of low pressure will lift northeastward over the north central portion of the country on Sunday. As this system interacts with warm, muggy air over the nations midsection, strong to severe thunderstorms will develop over the northern Plains and the upper Mississippi Valley. Severe thunderstorms will be possible over northern Minnesota and northwest Wisconsin. These thunderstorms will be capable of producing large hail, dangerous straight line winds and isolated tornadoes. Additionally, heavy rain associated with this system will bring a chance of flash flooding to northeast Montana and northwest North Dakota. Isolated thunderstorms will also linger over parts of the Pacific Northwest and the upper Intermountain West. Temperatures are forecast to drop 10 to 20 degrees below normal from the upper Intermountain West to the upper Mississippi Valley on Sunday.
Just to the south, monsoonal moisture will trigger afternoon and evening thunderstorms across the central and southern Rockies and parts of the Great Basin. The West Coast will stay mostly clear of wet weather due to a ridge of high pressure over the eastern Pacific.
A cold front extending from the middle Mississippi Valley to the Southeast will collide with a warm, humid air mass from the Gulf of Mexico. Rain and thunderstorms will develop over the southern Ohio Valley, the Tennessee Valley, the Southeast and the eastern Gulf Coast. The northern Mid-Atlantic and the Northeast will avoid wet weather.
Comments will take a few seconds to appear.