Here's how Tropical Storm Hilary will impact Bay Area, Southern California

ByDrew Tuma KGO logo

Thursday, August 17, 2023

Here's how Tropical Storm Hilary will impact California

Tropical Storm Hilary won't make landfall in California, but it's still having an impact on our weather.

SAN FRANCISCO (KGO) -- A newly-formed tropical storm named Hilary is making its rounds in the headlines. California will not see a hurricane making landfall. However, it will not be immune from the remnants of Hilary. There will be a threat of flooding rains across Southern California from Sunday through Tuesday.

TROPICAL STORM HILARY

As of 11 a.m. Wednesday, Hilary had winds of 40 mph and is expected to strengthen into a major Category 3 hurricane by Saturday morning. As Hilary moves north, she is expected to weaken dramatically. By the time she approaches the California-Mexico border, she will likely no longer be a tropical storm. The rapid intensification and weakening have to do with ocean water temperatures.

OCEAN TEMPERATURES

Hurricanes require ocean temperatures above 80 degrees to survive. Hilary is currently sitting in 85-degree water and will remain in those warm waters through Saturday. That is why we anticipate a rapid strengthening. As Hilary moves closer to Baja California, ocean temperatures will quickly cool into the 70s and eventually the 60s along the California coast.

That temperature drop may not seem like a lot but ocean temperatures in the 70s will essentially kill Hilary and water in the 60s will never support a tropical system. Thus, we see a very rapid weakening as the system approaches the California-Mexico border.

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HEAVY RAIN THREAT IN SOCAL

The remnants of Hilary will still be a threat to Southern California Sunday through Tuesday. NOAA has outlined a large portion of SoCal for the threat of flash flooding.

BAY AREA IMPACTS

We are likely to see increased clouds and increased humidity Sunday through Tuesday due to the remnants of Hilary. We will monitor the track of this storm and any small shifts would mean an increased chance for light rain here Monday and Tuesday. That is something we will fine-tune in the coming days.