News Summary
San Diego County is experiencing unseasonable weather as remnants of Tropical Storm Mario bring rain, thunderstorms, and a flood watch. Areas may see inconsistent rainfall, with possible brief localized flooding. Temperatures are expected to dip, and while coastal areas may dry out by Friday, isolated thunderstorms could linger. Forecasters predict a return to sunnier skies and warmer temperatures over the weekend, with a potential for more tropical moisture early next week.
San Diego, California – Unseasonable Rain and Thunderstorms Forecasted
A significant weather event is impacting San Diego County as a mass of moisture from former Tropical Storm Mario moved in late Wednesday afternoon. Thunder, lightning, and rain are expected to persist through Thursday and potentially into Friday, leading to a flood watch in effect from 5 a.m. Thursday to early Friday for the eastern parts of the county.
The National Weather Service (NWS) has indicated that rainfall will be inconsistent, with some areas experiencing small amounts while others could see heavier downpours, particularly during thunderstorms. By 4 p.m. on Wednesday, instances of lightning were reported across several areas, including Mission Valley, Allied Gardens, San Diego Bay, La Mesa, El Cajon, and Palomar Mountain.
Rainfall is part of a broader system affecting Southern California and the Southwest U.S., delivering overcast skies, scattered showers, and possible thunderstorms continuing until Friday. Satellite imagery confirms extensive cloud coverage and moisture moving in from the south and southwest. Residents in higher terrain areas may receive between one to two inches of rain, while others may struggle to accumulate even one-tenth of an inch.
Consequently, although a widespread flooding event is not anticipated, brief localized flooding may result from repeated heavy downpours. The NOAA’s Weather Prediction Center has determined that there is a Level 2 out of 4 flash flood threat for inland areas of Central and Southern California. Flood watches encompass nearly 7 million residents across several desert and mountain communities, but notably exclude downtown Los Angeles and San Diego.
Tropical Storm Mario, which reached its peak intensity with maximum sustained winds of 65 mph, weakened after interacting with cool sea temperatures and dry air. Meteorologists have noted that rainfall from the storm’s remnants is not anticipated to provide significant relief from long-term drought conditions in the region.
In response to the weather changes, temperatures across Southern California are expected to dip by 5 to 10 degrees below the seasonal averages due to increased humidity and cloud cover. Daytime high temperatures are forecasted to be in the 70s along the coast, in the 80s for inland valleys, and lower 90s in desert communities.
By Friday, coastal areas of San Diego may start to dry out; however, lingering showers and isolated thunderstorms could persist in deserts and the interior Southwest. As the weekend approaches, forecasters predict sunnier skies and a warming trend, with highs expected to return to the 80s and 90s.
There is a potential for another wave of tropical moisture to reach Southern California on Sunday and Monday, though the specifics remain uncertain. Currently, the chance of rain along the coast from Los Angeles County to San Diego County during the Wednesday night to Thursday morning timeframe ranges between 50% to 60%. Inland areas, such as the Coachella Valley, face a rain probability of 20% to 30%.
This weather system, with its mix of rain and thunder, marks an atypical climate event for the region, which is typically characterized by arid conditions. Residents are advised to stay informed about weather developments and to take precautions against the potential impacts of thunderstorms and localized flooding.
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Additional Resources
- Fox 5 San Diego: Tropical Storm Mario Brings Rain
- Google Search: Tropical Storm Mario San Diego
- Desert Sun: Flood Watch in Southern California
- Encyclopedia Britannica: California Weather
- NBC San Diego: Today’s San Diego Forecast
- Google News: San Diego Weather
- Times of San Diego: Tropical Storm Mario Showers
- Google Search: Weather Forecast San Diego
- CBS 8: Tropical Storm Mario Impact on San Diego
- Google Scholar: California Flooding Weather
Author: STAFF HERE SAN DIEGO WRITER
SAN DIEGO STAFF WRITER The SAN DIEGO STAFF WRITER represents the experienced team at HERESanDiego.com, your go-to source for actionable local news and information in San Diego, San Diego County, and beyond. Specializing in "news you can use," we cover essential topics like product reviews for personal and business needs, local business directories, politics, real estate trends, neighborhood insights, and state news affecting the area—with deep expertise drawn from years of dedicated reporting and strong community input, including local press releases and business updates. We deliver top reporting on high-value events such as Comic-Con International, San Diego County Fair, and San Diego Pride Festival. Our coverage extends to key organizations like the San Diego Regional Chamber of Commerce and United Way of San Diego County, plus leading businesses in biotechnology, healthcare, and technology that power the local economy such as Qualcomm, Illumina, and Scripps Health. As part of the broader HERE network, including HEREAnaheim.com, HEREBeverlyHills.com, HERECostaMesa.com, HERECoronado.com, HEREHollywood.com, HEREHuntingtonBeach.com, HERELongBeach.com, HERELosAngeles.com, HEREMissionViejo.com, and HERESantaAna.com, we provide comprehensive, credible insights into California's dynamic landscape.
