Weather across America

(NATIONAL) Extremely dangerous heat wave expands from Midwest to East Coast, severe weather and excessive rainfall potential for portions of the Great Plains, Upper Midwest and Great Lakes, and extreme heat shifts from the Northern Plains to the Midwest and Great Lakes and then the East Coast.

Numerous daily record maximum and minimum temperatures are expected over the Midwest to East Coast through Wednesday. Light winds, sunny skies, and a lack of overnight cooling will pose a significant risk to those without adequate cooling and/or hydration. The most significant heat impacts are anticipated across the Mid-Atlantic and Ohio Valley. 

Densely populated urban areas like Columbus, OH; Pittsburgh, PA; and Washington D.C. are among the most vulnerable. Heat related illnesses increase significantly during extreme heat. Wear lightweight and loose fitting clothing. Take action when you see symptoms of heat exhaustion and heat stroke.  

Elsewhere, a slow moving surface front will be the focus for thunderstorm activity across the Central U.S. early this week. Dryline storms could produce training cells that may lead to flash flooding in parts of the Southern High Plains Sunday and Monday. Thus, a slight risk (at least 15%) of excessive rainfall is in effect from southeastern New Mexico to west Texas.

Storms forming along the surface front over the Great Plains could turn severe over the next couple of days, which is why the Storm Prediction Center issued a pair of slight risks (level 2/5) for wide swaths of the Plains and Upper Midwest/Great Lakes, citing severe gusts and hail as the main threats. Some storm cells could produce additional flash flooding across portions of northern Kansas, southeastern Nebraska and much of Iowa, where a slight risk of excessive rainfall is in effect on Monday. 

Sunday's high temperatures in parts of the Northern Rockies/High Plains, Great Basin and Intermountain West will be between 20-35 degrees below average. Snow showers are also possible over the peaks of the different mountain ranges within the Northern Rockies of central Idaho, southwest Montana and northwest Wyoming Sunday.