Southern California is bracing for a dramatic shift in weather this weekend, following an unusually intense and prolonged heatwave earlier in October. A rare Tropical Storm Watch has been issued for portions of the region, signaling a potentially historic weather event.
On Friday, the National Hurricane Center issued the watch, which covers San Diego County and extends south into northern Baja. This marks only the second time in recorded history that such a watch has been issued for the state of California, with the only other instance being Tropical Storm Hilary just three years ago.
The forecast for the coming days has proven challenging due to an exceedingly rare atmospheric setup. A deep North Pacific trough is moving southward, pushing an upper-level low towards Baja and drawing Tropical Storm Rachel rapidly northeastward towards the North Baja or even the Southern California coast. Forecasters anticipate the storm's closest approach between Saturday night and Sunday morning.
Saturday is expected to serve as a transition day, with a more active weather pattern developing. Showers and the potential for thunderstorms could begin as early as Saturday, driven by an influx of tropical moisture and atmospheric instability. The most significant impacts are expected to sweep across parts of Southern California quickly overnight into the early hours of Sunday.
What makes this scenario particularly unusual is the expectation that the storm will actually hold together and even strengthen somewhat as it approaches the coast. This is remarkably rare for this far north, typically hindered by cooler ocean waters. However, current sea surface temperatures off Southern California and Baja are reportedly more than 10 degrees higher than normal, and the developing west coast trough and strengthening jet stream may support such a potent tropical storm making landfall.
The exact point where the storm makes landfall will have significant implications for local weather. Should the storm cross the border into California, it would be the first time a tropical storm has made landfall on the Southern California shore since September 1939, when a storm hit Long Beach. Historically, a hurricane impacted San Diego in 1858, further highlighting the potential for a truly historic scenario this weekend.
Regardless of where Rachel ultimately makes landfall, significant weather impacts are expected across the broader region. Heavy rains and flash flooding are considered a near certainty across parts of California, Arizona, Nevada, and Utah. Along the Southern California coast, dangerous surf and coastal flooding are likely. Additionally, gusty and potentially damaging winds are expected near and to the east of the storm's center. Strong thunderstorms, with the potential for tornadoes, cannot be ruled out over the weekend.
Residents are advised to stay weather aware and keep informed through reliable and updated weather sources, especially if travel is planned for areas of greatest concern.
