ABC News(NEW YORK) — Monsoon season begins Friday in the Southwest, which could see flash flooding.Phoenix and Tucson, Arizona, which haven’t seen rain in more than three months, could see 1 to 2 inches of precipitation, courtesy of Hurricane Bud.Monsoon season runs from June to September. It is characterized by shifts in wind patterns in the Southwest. Instead of dry wind coming from the west, the wind comes from the south and even southeast, with the tropical Pacific Ocean and the Gulf of Mexico bringing moisture to produce thunderstorms and rain in the arid Southwest.Red flag warnings and wind advisories, in addition to flash flood watches, are converging on the Southwest.As of early Friday morning, 43 wildfires were burning in the United States, about half of them in the West and half in Alaska.Parts of southern Arizona and New Mexico may see more than 2 inches of rain.More than 120 damaging-storm reports were produced Thursday from the Dakotas to the Carolinas. North Dakota reported a tornado.Three people in Florida were injured by lightning as strong thunderstorms rolled through the state.Severe weather is expected Friday in the Upper Midwest, particularly near the Minnesota Twin Cities. Damaging winds and tornadoes remain the biggest threats.On Saturday, stormy weather will extend from South Dakota to Michigan, with the biggest threats being damaging wind, hail and potential tornadoes.Summer is coming. An excessive heat watch has been issued this weekend in Chicago as temperatures may climb to the mid-90s, with humidity making it feel like it is 100 to 105 degrees.A heat advisory also was issued in Kansas City; St. Louis; Minneapolis, Minnesota; and Des Moines, Iowa, with the heat moving northeast on Sunday.Late Sunday and into Monday, temperatures are expected to be nearly 100 degrees in Washington and the mid-90s in New York. Copyright © 2018, ABC Radio. All rights reserved.