Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 422 PM EDT Wed Jul 22 2015 Valid 00Z Thu Jul 23 2015 - 00Z Sat Jul 25 2015 ...Severe thunderstorms possible for the Northern Plains and Upper Midwest... ...Widespread heat advisories across the deep South... A developing low pressure system and associated fronts will push toward the Pacific Northwest, British Columbia and Alaskan Coast over the next couple of days. Showers and few thunderstorms will be possible for portions of British Columbia and Alberta through Friday evening. Temperatures are expected to cool a few degrees with this system. Th frontal system that extends from the Canadian Prairies to the the Intermountain West Wednesday will track south and east through Friday evening into the Northern and Central Plains. Showers and thunderstorms are forecast to accompany this system through the end of the week. The Storm Prediction Center forecast for Thursday highlights a slight risk for severe thunderstorms for the Dakotas and extreme western Minnesota; and across the Upper Mississippi River Valley on Friday. Much of the eastern third of the U.S. will have more temperate conditions for the next couple of days. The cold front passed through and brought cooler, less humid air to the Ohio River Valley, New England and Mid-Atlantic areas Monday and Tuesday; however, the front has stalled from the Carolinas west to Oklahoma. Showers and thunderstorms will focus near this boundary through Friday evening. Excessive heat will persist over much of the deep South as long as the hot and humid airmass remains in place. Additionally, monsoonal moisture and diurnal heating will continue to aid in the development of showers and thunderstorms over parts of the Southern Rockies through the end of the week. Campbell Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_wbg.php