After creating dozens of lightning strikes and sudden bursts of rain on Tuesday, the first significant storm system of the fall season dumped even heavier rainfall on its second day over San Diego County.
Heavy rain Wednesday afternoon prompted a Flash Flood Advisory for parts of San Diego County including Chula Vista, Oceanside, Carlsbad, Temecula, El Cajon, Vista, Encinitas, National City, La Mesa and Poway through 3:15 p.m.
The National Weather Service said a heavy band of rain and thunderstorms was moving across western and northern San Diego County.
A flash flood watch was in effect for inland areas, mountains and deserts until Thursday morning at 1 a.m., according to the NWS.
The NWS also issued a Special Marine Warning for the San Diego coast from San Onofre to the U.S.-Mexico border until 9:45 p.m. The warning meant severe thunderstorms were present capable of producing "waterspouts" strong enough to damage and even overturn boats.
Since 8 a.m. on Tuesday, the storm system had already dumped nearly 3.9 inches of rain and 2 inches of snow on Palomar Mountain. The County Department of Public Works said snow had fallen at 4,500 feet and above, and said chains were required on vehicles traveling past that mark.
Rainfall totals in Valley Center were recorded at 4.31 inches and in Ramona at 3.12 inches. The La Jolla pump station and Otay Mountain also recorded more than 2 inches of rain while Borrego Springs recorded more than an inch.
By the time the storm system moves out of the region on Thursday, an additional one to two inches of rain and possibly some mountain snowfall is expected, NBC 7 Meteorologist Sheena Parveen said.
For the latest rainfall totals from the National Weather Service, visit here.
The scattered bursts had the potential to cause flash flooding during the storm's three-day stay over San Diego, and at least one warning went into effect on Tuesday.
The heaviest rainfall was expected between Wednesday evening and Thursday, NBC 7 Meteorologist Sheena Parveen said.
The steady rain amde for slick roads across the county, and caused a big rig to jackknife on I-15 near Adams Avenue. The crash caused at least 25 gallons of diesel fuel to spill into the roadway.
A Vista family had their dinner interrupted by water rushing into their home. They were gathered at the table when water began rushing in as if it was coming from "an open hydrant." Before they knew it a pool of water had reached above their ankles.
Soon after they noticed a drain in their front yard had clogged.
"It is really frustrating because we just bought the house in July. All these problems we have to fix," the homeowner said.
Flooding also shut down city streets like Quarry Road between State Route 125 and Lakeview Road in Spring Valley on Tuesday and Wednesday.
Country Club Drive in San Marcos was clsoed Tuesday evening and flooding also closed down the intersection of Discovery Street and Via Vera Cruz.
Several spinouts were reported on San Diego's slick roadways Wednesday morning. NBC 7 Traffic Anchor Ashley Matthews said at one point, California Highway Patrol officers conducted a traffic break on Interstate 15 in Miramar to slow down drivers.
The storm moved into San Diego County Tuesday afternoon and was a drastic shift from San Diego's hot and dry conditions on Sunday, which prompted a Red Flag Warning for the county.
More than three dozen lightning strikes were recorded from 11 a.m. to 11 p.m. on Tuesday. At least two strikes hit a tree in Ramona, igniting one in flames and causing a portion of the second to topple onto a home.
Between Monday and Wednesday, temperatures were expected to drop about 20 degrees as a cold front from the north clashes with tropical moisture from the south, according to the National Weather Service.
"This sets the stage for widespread rain and areas of heavy rain with mountain snowfall," according to the National Weather Service.
Southern California mountains above 6,000 feet could be topped with snow before the storm system moves out of the area late Thursday, though it is unlikely that San Diego's ranges will get anything more than a dusting.
Officials were taking measures to prepare for the storm. The county was offering free sandbags to residents in aniticipation of potential flooding.
This rainfall comes after the National Drought Mitigation Center Thursday designated much of California, including San Diego and Imperial Counties, as "abnormally dry" to "moderate drought" in some areas, for the first time since early 2019.
San Diego has not seen any rain for months, but this coming rainfall probably will not reverse the beginning signs of drought. Two inches of rain would be needed to bring San Diego out of its rain deficit, NBC 7 reported Friday.
Elephants at the San Diego Safari Park seemed to enjoy the natural creation of muddy rain created by Wednesday's downpour.