People in four states across the U.S. Southwest and California were warned of dangerous fire weather conditions on Monday, with dozens of counties under red flag warnings. The National Weather Service (NWS) cautions that a red flag warning indicates critical fire weather conditions are either underway or likely to develop shortly.

Low humidity and strong winds are forecast through Monday, prompting a red flag warning for a swath of Northern California. By midweek, temperatures may reach the 90s in parts of the inland Bay Area.