Rare Tropical Storm Watch Issued for San Diego as Rachel Nears

For only the second time in recorded history, the National Hurricane Center has issued a Tropical Storm Watch for Southern California, as Tropical Storm Rachel — a system that earlier peaked as a Category 3 hurricane — bears down on the California-Mexico border, threatening flooding rain, gusty winds, coastal flooding and even mountain snow across the Southwest.

The watch, issued Oct. 9 and effective through Oct. 13, covers San Diego County and extends west to San Clemente Island. As FOX Weather reported, the only other time the NHC issued such a watch for Southern California was ahead of Hurricane Hilary in 2023, which brought heavy rain and flooding to the California desert and other parts of the Southwest.

A Storm Re-Intensifying on Approach

Rachel formed Sept. 27 in the Eastern Pacific and strengthened to a Category 3 hurricane with 120 mph winds and a minimum central pressure of 950 mbar before weakening, according to Wikipedia’s meteorological record. As of Friday morning, it sat about 900 miles west of the southern tip of Baja California, tracking toward San Diego.

What makes the system unusual is that Rachel is forecast to re-strengthen slightly into a strong tropical storm before landfall, with sustained winds of roughly 60 to 65 mph — not far below the 74 mph hurricane threshold — despite dry air and a stable atmosphere.

“Remarkably, despite dry air and a stable atmosphere, this exact trough positioning combined with record-warm ocean temperatures may actually allow Rachel to re-strengthen slightly into a strong tropical storm before landfall, something that is now explicitly predicted by the NHC,” wrote climate scientist Daniel Swain of Weather West and UCLA. “That, in itself, is exceptionally unusual in this part of the world.”

Warnings for Wind, Waves and Flooding

Tropical-storm-force winds of at least 34 mph are expected to arrive as early as Saturday night and ramp up Sunday, Oct. 11. Coastal communities are warned of 6-to-10-foot waves, heightening erosion risks. As the National Weather Service cautioned, “very strong winds will cause hazardous seas which could capsize or damage vessels.”

A Level 2 out of 4 flash flood threat reaches across a large portion of the Southwest from Southern California to Utah, including Phoenix and Las Vegas, where 2 to 3 inches of rain is possible. Moisture from the system is expected to reach as far north as Montana, fueling a fall snowstorm across Montana and northern Wyoming, plus snow in the higher elevations of the Sierra Nevada.

In San Francisco, meteorologists noted that major coastal flooding was already underway Friday in Newport Beach, with coastal flood warnings in effect from Los Angeles to San Diego until Sunday afternoon. Sea levels are running 1 to 2 feet above normal, and forecasters said Sunday morning’s high tide in San Diego Bay could match its all-time record of 8.2 feet.

Warm Oceans Behind the Rarity

The key factor allowing a weakened system to maintain and regain strength is the record-warm Pacific Ocean. Sea surface temperatures along Rachel’s path are more than 10 to 13 degrees Fahrenheit above average, with Scripps Institution of Oceanography measuring 73 degrees Fahrenheit at Scripps Pier on Oct. 9 — tied for the hottest ever recorded on that date.

Swain attributes the warmth to a “trifecta”: an extremely strong 2026-2027 El Niño, a severe pre-existing marine heatwave, and long-term human-caused climate change. A coastally trapped Kelvin wave is also raising sea levels 12 to 18 inches above usual in Southern California.

“Ocean temperatures anomalies of this magnitude are, quite frankly, astonishing (and yes, they are clearly record-breaking) — made possible by a combination of an extremely strong El Niño acting atop a severe pre-existing marine heatwave amplified by climate change,” Swain wrote.

The setup follows one of Southern California’s worst late-season heatwaves on record. Downtown Los Angeles exceeded 100 degrees on five consecutive days — the longest such October streak ever — while San Diego saw two consecutive 100-plus days, tying its October record. The incoming storm is expected to break the heat.

A Region on Guard

The City of San Diego said it is preparing for potential flooding from rain combined with high tides, warning that low-lying areas around Midway and Mission Beach could see localized inundation. “Road closures are anticipated, especially in the Midway area at Frontage Road and Pacific Coast Highway,” the city said in an Oct. 9 press release.

City crews are cleaning storm drains, inspecting and clearing channels, and staging temporary pumps. “Our teams are working diligently to prepare the City’s stormwater system for the incoming rain, but community preparedness is just as critical, especially with El Niño in the forecast,” said Stormwater Department Director Todd Snyder.

A Multi-Storm Weekend

Rachel is not the only system threatening land this weekend. Hurricane Simon is forecast to rapidly intensify into a Category 4 and make landfall near Puerto Vallarta, Mexico, while Hurricane Isaias is expected to strike the northern Gulf Coast. According to FOX Weather hurricane specialist Bryan Norcross, “It is forecast to intensify into a Category 4 before impacting the coast. It will pass close to Puerto Vallarta about Sunday. It’s unusual for a hurricane to affect that city directly.”

With Isaias making landfall along the northern Gulf Coast late Friday, two tropical systems could be affecting the Gulf and West coasts simultaneously — something that has occurred only twice since 1963.

What to Watch

Considerable uncertainty remains over Rachel’s exact track. Models have converged on a likely landfall between Ensenada, Mexico and San Diego, though a more northerly turn into San Diego or Orange County remains possible — with higher-end impacts. Swain estimates the single likeliest outcome as a moderate-impact scenario with landfall south of Tijuana, but noted a growing possibility of a direct San Diego County hit.

A more northerly trajectory could bring stronger winds, heavier rainfall and significant coastal flooding to San Diego and surrounding areas. As the region braces, the coming days will test how well Southern California — and the wider Southwest — can absorb a storm that, in most years, would never have reached it at all.