Intense Weather Expected: Extreme Heat and High Humidity

The coming days bring intense weather, marked by extreme heat and high humidity. This follows a dramatic weekend with coastal flooding, rain, and dangerous surf caused by Tropical Storm Marie. A major increase in temperatures is expected by Tuesday, with a rise of 10 to 20 degrees above normal, affecting even coastal areas. Downtown Los Angeles and Long Beach could experience highs of 96 to 98 degrees, while further inland temperatures may surpass 105 degrees.

Nighttime will offer little reprieve as lows in the Los Angeles Basin are predicted to remain in the mid-70s. Wednesday might prove even warmer. David Gomberg, lead meteorologist at the National Weather Service in Los Angeles-Oxnard, notes that lingering moisture from Marie, along with the heat, may exacerbate discomfort and heat stress. A heat advisory is issued for Wednesday and Thursday, with potential escalations if conditions worsen.

If the clouds don’t materialize, then Wednesday could be a real problem, and temperatures could really jump up, said Gomberg. He advised residents to hydrate, stay indoors in air-conditioned spaces, and check on vulnerable relatives and neighbors.

Flooding from the weekend has caused lingering high surf and coastal flooding advisories, effective until 11 p.m. Tuesday. Continued caution is urged as rough ocean conditions persist. The high surf and rip currents could present significant hazards, such as capsizing smaller vessels, displacing individuals from jetties, and pulling swimmers out to sea.

Anybody who’s inexperienced needs to stay away from the surf zone right now, warned Gomberg, cautioning that waves might appear tame initially, only to grow surprisingly large and dangerous.

Significant impacts were felt on south-facing beaches like Long Beach and Malibu, particularly due to a combination of intense wave activity and higher-than-normal tides. The tides, combined with an ocean heatwave and developing El Niño, have contributed to unusual flooding. High tide levels reached 6.7 feet on Sunday and are expected to peak at 7 feet Monday evening and 7.2 feet Tuesday.

Rainfall, unusual for this time of year, has worsened drainage issues. Parts of Los Angeles County received over 1.25 inches of rain on Sunday. High tides, coupled with rainfall, caused street debris and pollutants to flush into the ocean. Beachgoers are therefore advised to avoid swimming through Wednesday due to potential bacteria spikes.

Los Angeles County’s topography, resembling a tilted bowl, allows rainwater to quickly find its way to the sea, gathering debris along its path. Unlike sewage, which is treated, this water carries impurities directly to the ocean. A practical guideline suggests waiting 72 hours post-rain before swimming, with some experts recommending five days, especially near river or outfall areas.