Forecasters are warning Americans to prepare for an intense heatwave this week that is building over parts of the United States, with several states approaching, or hitting the triple-digit high temperatures. “It’s going to be a real oppressive week with dangerous heat and hot conditions,” the National Weather Service said. “Excessive heat watches are up across much of the Pacific Northwest,” it added. “Meanwhile, heat advisories are in effect for a good part of the south-central U.S. and parts of western New York state.” The agency noted that triple-digit temperatures and above-average heat are possible in much of the Great Plains and Upper Midwest states. Daily high temperatures will also be “near-record setting” in the central and southern High Plains. “Pretty much everyone across the CONUS can expect some temperatures in the ‘Ooof’ zone this week,” forecasters said. An excessive heat warning was issued for Tuesday across the West Coast …