The National Weather Service said a red flag warning was in effect until Friday evening.

CNN: SHARE THIS

Generally, a bearish momentum divergence is a red flag warning signal, which often presages a pullback or correction.

FORBES: Home Builders Could Become Heartbreakers Again

The National Weather Service in San Diego said a red flag warning was in effect until Friday evening.

CNN: Evacuations begin as California wildfire grows

And, this whole medication-forgetting incident is a red flag warning.

FORBES: Wake-Up Call: Mom's Trip To The Emergency Room

The blaze quickly moved through the area as Southwest Idaho remained under a red flag warning Sunday and Monday because of high temperatures, low humidity and high winds conditions conducive to explosive and destructive fires.

MSN: Nuns, Boy Scouts among new wildfire evacuees

"It also is kind of a warning sign or red flag that hey, we really need to tackle this problem, " he said.

CNN: CO2 levels hit new peak at key observatory

Friday's warning was "a major red flag" and "quite a bit more expansive" than past alerts, said Kathleen Fairfax, vice president for global education at Arizona State University.

CNN: U.S. broadens Mexico travel warning