Long Beach is expected to hit 87 degrees today and other Southland communities will continue to wilt in 100-degree weather as the region’s first heat wave of Summer 2019 enters its fifth day.

A heat advisory issued by the NWS will go into effect at 10 a.m. in the San Fernando, Santa Clarita and San Gabriel valleys and the Santa Monica Mountains Recreational area. It will expire at 8 tonight.

“The heat will create a dangerous situation in which heat illnesses are possible, especially for the elderly and for people working outdoors,” warned the NWS.

The National Weather Service forecast a combination of partly cloudy and sunny skies in L.A. County, along with highs of 77 degrees in Avalon and at LAX; 87 in Downtown L.A. and Long Beach; 89 on Mount Wilson; 97 in Pasadena; 101 in Palmdale; 102 in Saugus and Lancaster; and 103 in Woodland Hills.

Temperatures are expected to dip down in Long Beach as the week continues with a high of 84 on Tuesday, 80 on Wednesday and 77 on Thursday, according to the NWS.