BIRMINGHAM, Ala. — Forecasters are warning about days of scorching, dangerous heat gripping a wide swath of the U.S. South and Midwest, where the heat index on Monday eclipsed 120 degrees in one town and climbed nearly that high in others. With temperatures around 100 degrees at midday and "feels like" temperatures soaring even higher, parts of 13 states were under heat advisories, from Texas, Louisiana and Florida in the South to Missouri and Illinois in the Midwest, the National Weather Service reported. "It feels like hell is what it feels like," said Junae Brooks, who runs Junae's Grocery in Holly Bluff, Mississippi.