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Heat Advisory in effect as temps rise above normal
The advisory, issued by the National Weather Service, will be in effect from 8 a.m. Tuesday through 9 p.m. Thursday for the valleys, the San Gabriel Mountains and the Los Angeles County inland coast, including downtown Los Angeles.
LOS ANGELES - A significant heat advisory is in effect for much of Southern California as a strong high-pressure system pushes temperatures well above seasonal norms.
The National Weather Service (NWS) is warning that peak heat and high humidity will create uncomfortable and potentially hazardous conditions through midweek before conditions begin to slightly ease.
What we know:
According to the NWS, the heat advisory covers the Santa Clarita, San Fernando, and San Gabriel valleys, the San Gabriel Mountains, and the Los Angeles County inland coast, including downtown Los Angeles.
"Afternoon high temperatures are forecast to be mostly around 3–8 degrees above normal, with coastal areas forecast to reach the upper 70s to upper 80s and low to middle 90s for inland valleys," according to the weather service.
A surge of mid-level moisture is also introducing higher humidity and a slight chance of showers or isolated thunderstorms through Wednesday.
Because the lower-level atmosphere is incredibly dry, forecasters noted that much of any rainfall could evaporate before reaching the ground, raising concerns over dry lightning and gusty winds.
What we don't know:
Meteorologists are unable to pinpoint exactly where or if isolated dry lightning storms will spark.
It's also unclear exactly how heavily the increased humidity will drive up the heat index (how it actually feels) in dense urban corridors compared to inland valleys.
Timeline:
Tuesday, 8 a.m.: The NWS heat advisory officially takes effect across LA County.
Tuesday – Wednesday: Mid-level moisture moves in, bringing peak humidity and a slight chance of isolated afternoon thunderstorms.
Wednesday Afternoon: The heatwave is expected to peak as a strong area of high pressure fully expands into Southern California.
Thursday, 9 p.m.: The heat advisory is scheduled to expire.
Friday – Weekend: Temperatures are expected to begin slowly easing, though they will likely remain slightly above normal through the weekend.
What they're saying:
The NWS emphasized the public health threat of the fast-moving system, warning that the heat could pose health risks for vulnerable groups, including young children, older adults, people without access to air conditioning, and those spending an extended time outdoors.
What's next:
A slow cooling trend begins on Friday, with above-average temperatures projected to stay high into Sunday.
What you can do:
- Stay hydrated: Drink plenty of water throughout the day, even if you do not feel actively thirsty.
- Check on others: Keep a close eye on neighbors, elderly relatives, and those who may not have functional air conditioning.
- Limit outdoor exposure: Reschedule strenuous outdoor activities or heavy exercise to the early morning or late evening hours.
- Protect pets: Never leave pets in parked cars and ensure they have plenty of shade and fresh water.
The Source: This report is based on official weather warnings, meteorological data, and public safety forecasts issued directly by the National Weather Service.