Potent thunderstorms across the central and eastern U.S. this week could trigger flash floods, damaging winds and possible tornadoes asCalifornia prepares for its first heat waveof the season. Several storms systems are aiming at differing parts of the country through the end of the week, with a multi-day system continuing to drench the Gulf Coast, developing severe storms over the Plains region and heavy rain brewing throughout the Mid-Atlantic,according to the National Weather Service. The heaviest rain is expected across the southern Plains and Gulf Coast, with storms threatening localized flash flooding, lightning, large hail and a few tornadoes, the weather service said. The cities most at risk include Houston, Austin, New Orleans and Atlanta, as well as portions of Oklahoma, Colorado and Kansas. Severe thunderstorm warnings and flash flood advisories were active across much of southern Texas on Wednesday, including the cities of San Antonio and Corpus Christi. Power outages were also mounting through the morning, with more than 21,000 homes and businesses in the dark,according to Poweroutage.us. Conditions in southern Texas deteriorated quickly on Wednesday as several inches of rain drenched the already-soaked region. The National Weather Service office in Austin and San Antonio warned of "life threatening flash flooding" in Blanco County and urged people to stay off inundated roads. "Doppler radar indicated thunderstorms producing heavy rain across the warned area," said the weather service office. "Additional rainfall amounts of 1 to 3 inches are possible in the warned area. Flash flooding is ongoing or expected to begin shortly." Earlier in the week, southern Texas, including San Antonio, was battered by a round of potent storms that unleashed flooding rain and massive, 5-inch chunks of hail. These storms are being fueled by a boundary separating cooler air in the north from humid, warm air spread across the Gulf Coast states. The set-up led to several major storms on Memorial Day that walloped the southern Plains and Southeast with strong wind gusts, a few tornadoes and large hail. The poor weather will continue through the week and intensify in some areas. More storms are expected to pound the Gulf Coast states on Thursday, from Houston to New Orleans. On Friday and into the weekend, heavy rain is expected to bear down on Southeast from northern Florida to the Carolinas. In the West,Californiaas well as parts of Nevada and Arizona are set to experience their fist heat wave of the season. Temperatures across California's Central Valley could reach into the triple digits and break daily records, according to the National Weather Service in Los Angeles. On Friday and Saturday, triple-digit temperatures are expected across southern Nevada, including the cities of Moapa and Las Vegas. More:Triple-digit heat in forecast as California braces for scorching summer This article originally appeared on USA TODAY:Severe thunderstorms brewing across U.S. trigger flood advisories
