Southern California – The remnants of Tropical Storm Juliette are making a noticeable impact on Southern California’s weather this week, bringing scattered showers, thunderstorms, and a significant cool down to the region. The National Weather Service in San Diego has issued forecasts signaling changes in monsoonal moisture and temperature patterns that residents should be aware of.
Monsoonal Moisture Declines as Juliette’s Remnants Arrive
Earlier this week, Southern California experienced monsoonal moisture that increased the likelihood of afternoon thunderstorms, especially in desert slopes across Riverside and San Diego Counties. However, the National Weather Service reports a decrease in this moisture today, reducing thunderstorm chances for the afternoon. Despite this decline, late tonight through Thursday evening, the remnants of Tropical Storm Juliette will introduce scattered showers and potential thunderstorms to southwestern California.
The areas most vulnerable to heavier rainfall and isolated flash flooding include the Riverside County mountains and the San Bernardino Mountains. Residents in these areas are advised to stay informed as the storm system progresses.
Significant Temperature Drop and Weather Changes Thursday
Thursday’s forecast predicts a marked cool down with temperatures dropping 10 to 15 degrees below average across the lower deserts and adjacent mountain areas. This shift contrasts sharply with recent warmer conditions and offers a welcome relief from the heat. The National Weather Service notes:
“While thunderstorms today will be less frequent, an increase in moisture from Tropical Storm Juliette’s aftermath will elevate the chance of scattered showers and some thunderstorm activity.”
Transition to Warmer and Dryer Conditions by Friday
Looking forward, Southern California will experience a warming and drying trend starting Friday. Temperatures in the Inland Empire and lower deserts of San Diego and Riverside Counties will rise slightly compared to Thursday, although coastal zones will remain relatively cool. Despite the warming trend, a slight chance of thunderstorms persists, albeit mainly over mountainous regions in the afternoon.
Weekend Outlook and Early Next Week Forecast
The drying pattern is expected to continue through the weekend, encouraging warmer temperatures across Southern California. However, this reprieve may be temporary. Early next week, meteorologists anticipate a return of monsoonal moisture, potentially resulting in an increase in thunderstorms, particularly in mountain and desert areas. This moisture influx will likely bring a subtle cooldown, according to the National Weather Service’s long-term forecast.
Impact on Aviation and Marine Activities
As Tropical Storm Juliette’s effects unfold, aviation and marine operations may encounter some challenges. Patchy low clouds could disrupt early morning flights, and thunderstorm activity on Thursday might cause erratic winds and lightning over open waters. Shipping and boating interests should remain alert through the week, although no severe maritime hazards are expected until Sunday.
Key Points to Remember:
- Monsoonal moisture declining today, lowering thunderstorm chances across desert areas.
- Scattered showers and thunderstorms expected from Tropical Storm Juliette’s remnants late tonight through Thursday.
- Heavier rainfall and isolated flash flooding risks mainly in Riverside and San Bernardino Mountains.
- Thursday brings a significant temperature drop, 10-15 degrees below average in lower deserts and mountains.
- Friday sees warming and drying trends with slight thunderstorm chances in mountains.
- Weekend remains warm and dry, but moisture and possible thunderstorms may return early next week.
- Aviation and marine activities may be disrupted due to low clouds and thunderstorms through Thursday.
