Weather Alerts For Diamond Bar, CA

Flood Watch National Weather Service Los Angeles/Oxnard CA 551 AM PST Mon Dec 22 2025 Cuyama Valley-Catalina and Santa Barbara Islands-Santa Clarita Valley-San Luis Obispo County Beaches-San Luis Obispo County Inland Central Coast-Santa Lucia Mountains-Southern Salinas Valley-San Luis Obispo County Interior Valleys-San Luis Obispo County Mountains-Santa Barbara County Central Coast Beaches-Santa Barbara County Inland Central Coast-Santa Ynez Valley-Santa Barbara County Southwestern Coast-Santa Barbara County Southeastern Coast-Santa Ynez Mountains Western Range-Santa Ynez Mountains Eastern Range-Santa Barbara County Interior Mountains- Ventura County Beaches-Ventura County Inland Coast-Lake Casitas- Ojai Valley-Central Ventura County Valleys-Los Angeles County Beaches-Palos Verdes Hills-Los Angeles County Inland Coast including Downtown Los Angeles-Western Santa Monica Mountains Recreational Area-Eastern Santa Monica Mountains Recreational Area-Calabasas and Agoura Hills-Western San Fernando Valley- Eastern San Fernando Valley-Southeastern Ventura County Valleys- Santa Susana Mountains-Southern Ventura County Mountains-Northern Ventura County Mountains-Interstate 5 Corridor-Western San Gabriel Mountains and Highway 14 Corridor-Eastern San Gabriel Mountains-Western Antelope Valley Foothills-Eastern Antelope Valley Foothills-Antelope Valley-Los Angeles County San Gabriel Valley- Including the cities of Goleta, Palmdale, Santa Barbara, Creston, Montecito Hills, Morro Bay, Paso Robles, Downey, The Angeles Crest Highway, San Gabriel, Santa Paula, Mill Creek, Topatopa Mountains, Northridge, Universal City, La Panza Range, Rancho Palos Verdes, Avalon, Lopez Lake, Vandenberg Space Force Base, Port Hueneme, Chatsworth, Cambria, Van Nuys, Oat Mountain, Meiners Oaks, Santa Ynez, Avila Beach, Matilija, Newhall, Malibu Lake, Warm Springs, Norwalk, New Cuyama, LAX, Buellton, Arroyo Grande, Long Beach, East Los Angeles, Pyramid Lake, Jalama Beach, Hollywood, Mount Baldy, Valyermo, Newbury Park, Pomona, Gaviota, Ozena, Figueroa Mountain, Woodland Hills, Santa Maria, Lancaster, Llano, Big Pine Mountain, Malibu Bowl, Lake Palmdale, Lompoc, Gorman, Torrance, Point Mugu, Oak View, Atascadero, Glendale, Rose Valley, Refugio State Beach, Pearblossom, Santa Margarita Lake, Acton, Topanga, San Miguel, East Ventura, Fillmore, Elizabeth Lake, Beverly Hills, San Rafael Mountain, Santa Clarita, Carrizo Plain, Shandon, Pismo Beach, Solvang, Ojai, Ventura, Wrightwood, Caliente Range, Hearst Castle, Santa Monica, Pasadena, Lake Los Angeles, Redondo Beach, Culver City, Burbank, San Marcos Pass, Carpinteria, La Canada Flintridge, Lockwood Valley, Irish Hills, Lake Castaic, El Capitan State Beach, Thousand Oaks, Lake Nacimiento, Los Olivos, El Monte, Mount Pinos, Templeton, Sunland, Lake Cachuma, Montecito, Nipomo, Oxnard, Camarillo, Tejon Pass, Westlake Village, Mount Wilson, San Luis Obispo, Compton, Valencia, Piru, Simi Valley, and Moorpark 551 AM PST Mon Dec 22 2025 ...FLOOD WATCH REMAINS IN EFFECT FROM TUESDAY AFTERNOON THROUGH WEDNESDAY EVENING... * WHAT...Flooding caused by excessive rainfall continues to be possible. * WHERE...A portion of southwest California, including the following areas, Antelope Valley, Calabasas and Agoura Hills, Catalina and Santa Barbara Islands, Central Ventura County Valleys, Cuyama Valley, Eastern Antelope Valley Foothills, Eastern San Fernando Valley, Eastern San Gabriel Mountains, Eastern Santa Monica Mountains Recreational Area, Interstate 5 Corridor, Lake Casitas, Los Angeles County Beaches, Los Angeles County Inland Coast including Downtown Los Angeles, Los Angeles County San Gabriel Valley, Northern Ventura County Mountains, Ojai Valley, Palos Verdes Hills, San Luis Obispo County Beaches, San Luis Obispo County Inland Central Coast, San Luis Obispo County Interior Valleys, San Luis Obispo County Mountains, Santa Barbara County Central Coast Beaches, Santa Barbara County Inland Central Coast, Santa Barbara County Interior Mountains, Santa Barbara County Southeastern Coast, Santa Barbara County Southwestern Coast, Santa Clarita Valley, Santa Lucia Mountains, Santa Susana Mountains, Santa Ynez Mountains Eastern Range, Santa Ynez Mountains Western Range, Santa Ynez Valley, Southeastern Ventura County Valleys, Southern Salinas Valley, Southern Ventura County Mountains, Ventura County Beaches, Ventura County Inland Coast, Western Antelope Valley Foothills, Western San Fernando Valley, Western San Gabriel Mountains and Highway 14 Corridor and Western Santa Monica Mountains Recreational Area. * WHEN...From Tuesday afternoon through Wednesday evening. * IMPACTS...Excessive runoff may result in flooding of rivers, creeks, streams, and other low-lying and flood-prone locations. Mud and debris flows will be possible across foothill and mountain areas, including recent burn scars. * ADDITIONAL DETAILS... - A moderate to strong atmospheric river will impact Southwestern California Tuesday through Wednesday. Heavy rainfall is expected with high rainfall rates. So, widespread urban flooding will be possible along with mud and debris flows across all foothills and mountain areas. - http://www.weather.gov/safety/flood PRECAUTIONARY/PREPAREDNESS ACTIONS... You should monitor later forecasts and be alert for possible Flood Warnings. Those living in areas prone to flooding should be prepared to take action should flooding develop. &&

Air Quality Alert Message Relayed by National Weather Service Los Angeles/Oxnard CA 111 PM PST Sun Dec 21 2025 Calabasas and Agoura Hills- Catalina and Santa Barbara Islands- Including the city of Avalon and Two Harbors. Eastern San Fernando Valley- Including the cities of Burbank, Glendale, and Universal City Eastern Santa Monica Mountains Recreational Area- Los Angeles County Beaches- Including the cities of Santa Monica, Torrance, and Long Beach Los Angeles County Inland Coast including Downtown Los Angeles- Including the cities of Inglewood, Downey, Norwalk, Beverly Hills, and West Hollywood Los Angeles County San Gabriel Valley- Including the cities of Pasadena, San Gabriel, and Pomona Malibu Coast- Including the city of Malibu Palos Verdes Hills- Santa Clarita Valley- Including the cities of Santa Clarita, Newhall, and Valencia Santa Susana Mountains- Western San Fernando Valley- Including the cities of Reseda, Woodland Hills, and Northridge Western Santa Monica Mountains Recreational Area- 111 PM PST Sun Dec 21 2025 ...AIR QUALITY ALERT: MANDATORY WOOD-BURNING BAN IN EFFECT... * WHAT...The South Coast AQMD has extended a mandatory wood-burning ban for residents in the South Coast Air Basin. The No-Burn rule bans burning wood, pellets, and manufactured fire logs in any indoor or outdoor wood-burning device. * WHERE...The South Coast Air Basin, which includes Orange County and non-desert portions of Los Angeles, Riverside, and San Bernardino counties. No-Burn Day alerts do not apply to areas above 3,000 feet in elevation, the Coachella Valley, or the High Desert. Homes that rely on wood as a sole source of heat, low-income households and those without natural gas service also are exempt from the requirement. * WHEN...Sunday and Monday. * IMPACTS...Particles in smoke can get deep into the lungs and cause health problems (including asthma attacks), increases in emergency room visits, and hospitalizations. No-Burn Days are needed to protect public health when fine particle pollution levels are expected to be high anywhere in the South Coast Air Basin. No-Burn Days are based on fine particle pollution levels that are forecasted for an entire 24-hour period, which may not be reflected in real-time air quality maps. PRECAUTIONARY/PREPAREDNESS ACTIONS... To protect your health, check current and forecasted air quality levels at www.aqmd.gov or download the mobile app at www.aqmd.gov/mobileapp. When air quality is poor in your area, limited extended or intense outdoor activity and remain inside with windows and doors closed. Run your air conditioner and/or an air purifier and avoid using devices that bring in outside air like a swamp cooler or whole house fan if you have other ways to stay cool. Additional details for this air quality alert are available at www.aqmd.gov/advisory. Information on the South Coast AQMD Check Before You Burn program is available at www.aqmd.gov/cbyb.