Dangerous heat is expected to build across the region this week, with the National Weather Service issuing a Heat Advisory for coastal and beach areas, including Santa Monica, from 10 a.m. Tuesday to 8 p.m. Thursday.
While Santa Monica will stay cooler than most places, temperatures are forecast to reach 85 to 105 degrees across the advisory area, with the hottest conditions expected Wednesday, particularly over interior locations. The National Weather Service office in Los Angeles/Oxnard said humid conditions will compound the heat, and warm overnight lows will offer little relief.
"There is a high risk for dangerous heat illness for anyone, especially for the very young, the very old, those without air conditioning, and those active outdoors," the agency said in its advisory.
Inland areas, including sections of Los Angeles County away from the coast, are under a more serious Extreme Heat Warning for the same period, reflecting the greater danger posed by higher temperatures away from the moderating effect of the ocean.
Forecasters are urging residents to drink plenty of fluids, stay in air-conditioned spaces, avoid direct sun and check on relatives and neighbors during the advisory period. People who must be outside are advised to wear lightweight, loose-fitting clothing and limit strenuous activity to early morning or evening hours. The National Weather Service noted that the Occupational Safety and Health Administration recommends frequent breaks in shaded or air-conditioned areas for anyone working outdoors, and stressed that heat stroke is a medical emergency requiring an immediate call to 911.
The heat is being driven by an amplifying upper-level ridge building over the region through midweek, according to the agency's area forecast discussion. A weather system will keep skies mostly cloudy Monday, holding temperatures close to Sunday's levels, but forecasters said a significant warm-up will begin Tuesday, with valley temperatures climbing to 100-110 degrees and interior coastal plain areas reaching the mid-90s by Wednesday. Widespread "Major HeatRisk" conditions are expected Wednesday as monsoonal moisture pushes humidity higher.
Before the heat takes hold, there is a chance for scattered showers and isolated thunderstorms Monday and Tuesday afternoons, mainly over interior mountain areas of Los Angeles and Ventura counties. Forecasters said any storms could produce gusty and erratic winds of 45 to 60 mph, along with brief heavy rain, and warned that lightning could spark new fires while outflow winds could fan existing ones.
Gusty northwest to north winds are also expected to develop from southern Santa Barbara County to the Interstate 5 corridor Tuesday afternoon through Wednesday night, with forecasters citing a 30% to 50% chance that wind advisories will be needed as a "Sundowner" wind event develops. A Fire Weather Watch has been issued for Wednesday afternoon through Thursday morning for interior sections of Los Angeles and Ventura counties.
Along the coast, a Beach Hazards Statement remains in effect through Wednesday evening for Los Angeles County beaches and the Malibu Coast, with dangerous rip currents and elevated surf expected from an enhanced southerly swell. Combined with abnormally high tides of 7.0 to 7.6 feet, forecasters said minor coastal flooding is possible in low-lying areas during evening hours. Offshore, small craft advisories are in effect through early Friday as northwest winds strengthen and seas build to more than 10 feet, with a 20% chance of gale-force conditions Wednesday into Thursday.
Hot conditions are expected to persist into Thursday before gradually easing over the weekend, as onshore flow returns and brings a chance of night and morning clouds and fog back to coastal areas by early next week.