Sunnyvale, CA Warnings, Watches and Advisories

Do not drive vehicles through flooded areas. The water depth or fast flowing water/mud/debris from a flash flood will make road conditions unsafe. Do not rely soley on data presented here or other third-party websites - always check your official national and local weather service agency website, socials, radio and/or TV stations for making critical decisions related to weather events.

Please carefully read each posted Warning and Alert as it relates to the area(s) being affected. We may provide a wider range of issued severe weather warnings for surrounding cities and counties, so some alerts may not directly impact this location. This is done to help with preparing for severe weather that may overlap or be heading towards Sunnyvale.

Use the Radar Maps link provided to understand the trajectory of a storm.

Fire Weather Watch issued November 2 at 5:13AM PDT until November 4 at 6:00PM PST by NWS San Diego CA

GUSTY NORTH TO NORTHEAST WINDS AND RELATIVE HUMIDITY NEAR 15 PERCENT WILL LEAD TO PERIODS OF CRITICAL FIRE WEATHER CONDITIONS SUNDAY NIGHT INTO LATE MONDAY AFTERNOON FOR PORTIONS OF THE COASTAL SLOPES OF THE SAN BERNARDINO COUNTY MOUNTAINS AND PORTIONS OF THE INLAND EMPIRE, MAINLY BELOW THE CAJON PASS. * WINDS...North 15 to 25 mph with gusts up to 45 mph. * RELATIVE HUMIDITY...As low as 15 percent. * IMPACTS...Any fires that develop will likely spread rapidly. Outdoor burning is not recommended. * LOCATION...San Bernardino and Riverside County Valleys-The Inland Empire and San Bernardino County Mountains-Including The Mountain Top And Front Country Ranger Districts Of The San Bernardino National Forest.

Wind Advisory issued November 2 at 5:09AM PDT until November 3 at 4:00AM PST by NWS San Diego CA

* WHAT...West winds 20 to 30 mph with gusts up to 50 mph expected. * WHERE...San Diego County Deserts and San Diego County Mountains. * WHEN...From 11 AM PDT this morning to 4 AM PST Sunday. * IMPACTS...Gusty winds will blow around unsecured objects; winds may cause small tree limb damage.

Wind Advisory issued November 2 at 5:09AM PDT until November 5 at 4:00PM PST by NWS San Diego CA

* WHAT...North to northeast winds 20 to 30 mph with gusts 35 to 45 mph expected. Local gusts up to 55 mph through wind prone passes and canyons. * WHERE...Orange County Inland Areas, Santa Ana Mountains and Foothills. * WHEN...From 7 PM Sunday to 4 PM PST Tuesday. * IMPACTS...Gusty winds will blow around unsecured objects. Tree limbs could be blown down and a few power outages may result. * ADDITIONAL DETAILS...Daytime relative humidity values of 15 to 20 percent (lowest in the Santa Ana mountains) combined with gusty north to northeasterly winds will create elevated fire weather conditions.

Beach Hazards Statement issued November 2 at 4:55AM PDT until November 4 at 7:00PM PST by NWS San Francisco CA

* WHAT...Long period northwest swell will result in an energetic surf zone resulting in an increasing risk of sneaker waves and increasing rip currents, then transitioning to a larger surf with strong rip currents, long beach run-up and large shore break on steeper beaches. Breaking waves of 10 to 14 feet are expected. * WHERE...San Francisco, Coastal North Bay Including Point Reyes National Seashore and San Francisco Peninsula Coast Counties. * WHEN...From Sunday afternoon through Monday evening. * IMPACTS...Large waves can sweep across the beach without warning, pulling people into the sea from rocks, jetties, and beaches. Sudden immersion in cold water can result in cold water shock even for the most experienced swimmers. Cold water shock can result in dramatic changes in breathing, heart rate and blood pressure, greatly increasing the risk of drowning in rough open waters.

Beach Hazards Statement issued November 2 at 4:55AM PDT until November 4 at 7:00PM PST by NWS San Francisco CA

* WHAT...Long period northwest swell will result in an energetic surf zone resulting in an increasing risk of sneaker waves and increasing rip currents, then transitioning to a larger surf with strong rip currents, long beach run-up and large shore break on steeper beaches. Breaking waves of 10 to 14 feet are expected. * WHERE...Southern Monterey Bay and Big Sur Coast County. * WHEN...From Sunday afternoon through Monday evening. * IMPACTS...Large waves can sweep across the beach without warning, pulling people into the sea from rocks, jetties, and beaches. Sudden immersion in cold water can result in cold water shock even for the most experienced swimmers. Cold water shock can result in dramatic changes in breathing, heart rate and blood pressure, greatly increasing the risk of drowning in rough open waters.

Winter Weather Advisory issued November 2 at 4:53AM PDT until November 2 at 11:00PM PDT by NWS Hanford CA

* WHAT...Snow expected above 6,000 feet. Total snow accumulations up to 5-7 inches expected, with 8 inches possible at the highest elevations. At Tioga Pass, there is a 39 percent chance of four or more inches of snow. * WHERE...Kaiser to Rodgers Ridge, Kings Canyon NP, Upper San Joaquin River, and Yosemite NP outside of the valley. * WHEN...Until 11 PM PDT this evening. * IMPACTS...Roads, and especially bridges and overpasses, will likely become slick and hazardous. Plan on slippery road conditions.

Winter Weather Advisory issued November 2 at 2:40AM PDT until November 2 at 11:00AM PDT by NWS Sacramento CA

* WHAT...Additional snow accumulations up to 3 inches above 6000 feet. * WHERE...West Slope Northern Sierra Nevada and Western Plumas County/Lassen Park Counties. * WHEN...Until 11 AM PDT this morning. * IMPACTS...Snow covered roads, chain controls, and travel delays are possible. Hazardous conditions could impact travel into the afternoon. * ADDITIONAL DETAILS...Scattered mountain snow showers will gradually diminish through the afternoon hours.

High Wind Warning issued November 2 at 1:48AM PDT until November 3 at 10:00AM PST by NWS Hanford CA

* WHAT...Northwest winds 25 to 35 mph with gusts up to 65 mph possible. * WHERE...Mojave Desert Slopes. * WHEN...From 8 PM PDT this evening to 10 AM PST Sunday. * IMPACTS...Damaging winds will blow down trees and power lines. Widespread power outages are expected. Travel will be difficult, especially for high profile vehicles. * ADDITIONAL DETAILS...This warning ends at 10 AM PST due to the end of Daylight Saving Time. The strongest wind will be from the intersection of Highway 58 and 14 and moving southwest along the slopes.

Wind Advisory issued November 2 at 1:23AM PDT until November 3 at 5:00AM PST by NWS Phoenix AZ

* WHAT...West winds 20 to 30 mph with gusts up to 50 mph expected. * WHERE...Southwest corner of Imperial County. * WHEN...From 5 PM PDT this afternoon to 5 AM PST Sunday. * IMPACTS...Difficult driving conditions, especially for larger vehicles traveling along roads with crosswinds. Light, unsecured objects may become airborne.

Wind Advisory issued November 2 at 1:23AM PDT until November 4 at 6:00AM PST by NWS Phoenix AZ

* WHAT...Northwest winds 20 to 30 mph with gusts up to 45 mph expected. * WHERE...Western portion of Joshua Tree National Park, and Eastern portion of Joshua Tree National Park. * WHEN...From 10 PM Sunday to 6 AM PST Monday. * IMPACTS...Difficult driving conditions, especially for larger vehicles traveling along roads with crosswinds. Light, unsecured objects may become airborne.

Wind Advisory issued November 2 at 1:23AM PDT until November 4 at 2:00PM PST by NWS Phoenix AZ

* WHAT...North winds 20 to 30 mph with gusts up to 45 mph expected. * WHERE...In Arizona, Parker Valley. In California, Chuckwalla Valley and Palo Verde Valley. * WHEN...From 11 PM MST /10 PM PST/ Sunday to 3 PM MST /2 PM PST/ Monday. * IMPACTS...Difficult driving conditions, especially for larger vehicles traveling along roads with crosswinds. Light, unsecured objects may become airborne.

Wind Advisory issued November 2 at 1:00AM PDT until November 4 at 4:00AM PST by NWS Las Vegas NV

* WHAT...North winds 15 to 25 mph with gusts up to 45 mph expected. * WHERE...In California, Cadiz Basin, Eastern Mojave Desert, and Morongo Basin. In Nevada, Lincoln County, Las Vegas Valley, Northeast Clark County, Sheep Range, Southern Clark County, and Spring Mountains-Red Rock Canyon. * WHEN...From 4 PM Sunday to 4 AM PST Monday. * IMPACTS...Gusty winds will blow around unsecured objects. Tree limbs could be blown down and a few power outages may result. * ADDITIONAL DETAILS...Crosswinds may create difficult driving conditions on Interstate 15 and Interstate 40.

Wind Advisory issued November 2 at 1:00AM PDT until November 4 at 4:00AM PST by NWS Las Vegas NV

* WHAT...North winds 20 to 30 mph with gusts up to 45 mph expected. * WHERE...White and Inyo Mountains, Eastern Sierra Slopes, Owens Valley, Death Valley National Park, Esmeralda and Central Nye County, and Western Clark and Southern Nye County. * WHEN...From 10 AM Sunday to 4 AM PST Monday. * IMPACTS...Gusty winds will blow around unsecured objects. Tree limbs could be blown down and a few power outages may result.

Wind Advisory issued November 2 at 1:00AM PDT until November 4 at 4:00PM PST by NWS Las Vegas NV

* WHAT...North winds 20 to 30 mph with gusts up to 50 mph expected. * WHERE...Lake Mead National Recreation Area, Lake Havasu and Fort Mohave, and San Bernardino County-Upper Colorado River Valley. * WHEN...From 4 PM PST /5 PM MST/ Sunday to 4 PM PST /5 PM MST/ Monday. * IMPACTS...Gusty winds will blow around unsecured objects. Tree limbs could be blown down and a few power outages may result. * ADDITIONAL DETAILS...Crosswinds may create difficult driving conditions on Interstate 40.

Fire Weather Watch issued November 1 at 2:36PM PDT until November 4 at 6:00PM PST by NWS Los Angeles/Oxnard CA

...FIRE WEATHER WATCH IN EFFECT SUNDAY EVENING THROUGH MONDAY ACROSS PORTIONS OF LOS ANGELES AND VENTURA COUNTIES DUE TO GUSTY SANTA ANA WINDS AND LOW HUMIDITIES... .A low pressure system is now taking a more inland track, resulting in reduced chances of rain on Saturday. As a result, any rainfall accumulation that does fall is expected to be less than 0.10 inches with some areas possibly not receiving any rainfall south of Point Conception. Behind this system, there will be strengthening northerly winds and a drying trend on Sunday that will bring elevated fire weather conditions to southern Santa Barbara county and the highway 33 corridor in Western Ventura county by Sunday afternoon and evening. By Sunday night and Monday, a Santa Ana wind event will potentially bring critical fire weather conditions to wind prone mountain and valley areas of Los Angeles and Ventura counties. A potentially stronger, more widespread, and longer duration Santa Ana wind event could bring widespread critical fire weather conditions to wind prone areas of Los Angeles and Ventura counties Wednesday into Thursday. The National Weather Service in Los Angeles/Oxnard has issued a Fire Weather Watch for gusty Santa Ana winds and low relative humidity, which is in effect from Sunday evening through Monday afternoon. * WINDS...Northeast 25 to 40 mph with localized damaging gusts up to 60 mph possible. * RELATIVE HUMIDITY...Falling to between 15 and 25 percent across downslope areas Sunday night into Monday. Isolated readings 10 to 15 percent possible on Monday in favored downslope areas. * IMPACTS...If fire ignition occurs, conditions are favorable for rapid fire spread and extreme fire behavior which would threaten life and property. * ADDITIONAL DETAILS...Another potentially stronger, more widespread, and longer duration Santa Ana wind event could bring widespread critical fire weather conditions to wind prone areas of Los Angeles and Ventura counties Wednesday into Thursday.

Fire Weather Watch issued November 1 at 2:36PM PDT until November 4 at 6:00PM PST by NWS Los Angeles/Oxnard CA

...FIRE WEATHER WATCH IN EFFECT SUNDAY EVENING THROUGH MONDAY ACROSS PORTIONS OF LOS ANGELES AND VENTURA COUNTIES DUE TO GUSTY SANTA ANA WINDS AND LOW HUMIDITIES... .A low pressure system is now taking a more inland track, resulting in reduced chances of rain on Saturday. As a result, any rainfall accumulation that does fall is expected to be less than 0.10 inches with some areas possibly not receiving any rainfall south of Point Conception. Behind this system, there will be strengthening northerly winds and a drying trend on Sunday that will bring elevated fire weather conditions to southern Santa Barbara county and the highway 33 corridor in Western Ventura county by Sunday afternoon and evening. By Sunday night and Monday, a Santa Ana wind event will potentially bring critical fire weather conditions to wind prone mountain and valley areas of Los Angeles and Ventura counties. A potentially stronger, more widespread, and longer duration Santa Ana wind event could bring widespread critical fire weather conditions to wind prone areas of Los Angeles and Ventura counties Wednesday into Thursday. * WINDS...North to northeast 15 to 30 mph with gusts 40 to 50 mph. Strongest winds near higher terrain, as well as the Highway 118 corridor in western San Fernando Valley and near Simi Valley. * RELATIVE HUMIDITY...Falling to between 15 and 25 percent across downslope areas Sunday night into Monday. Isolated readings 10 to 15 percent likely on Monday in favored downslope areas. * IMPACTS...If fire ignition occurs, conditions are favorable for rapid fire spread and extreme fire behavior which would threaten life and property. * ADDITIONAL DETAILS...Another potentially stronger, more widespread, and longer duration Santa Ana wind event could bring widespread critical fire weather conditions to wind prone areas of Los Angeles and Ventura counties Wednesday into Thursday.

Winter Weather Advisory issued November 1 at 2:27PM PDT until November 2 at 11:00AM PDT by NWS Reno NV

* WHAT...Snow. Snow accumulations up to 1 inch for communities along Highway 395 with 2 and 6 inches above 8000 feet. Winds gusting as high as 60 mph over Sierra ridges. * WHERE...Mono County. * WHEN...From 11 PM this evening to 11 AM PDT Saturday. * IMPACTS...Plan on slippery road conditions, including Highways 120 and 395.

Winter Weather Advisory issued November 1 at 2:27PM PDT until November 2 at 11:00AM PDT by NWS Reno NV

* WHAT...Snow above 5000 feet. Snow accumulations up to 2 inches in western Lassen and the Lakes Basin in Plumas County. Higher totals near 4 inches are possible over Yuba Pass. * WHERE...Lassen-Eastern Plumas-Eastern Sierra Counties. * WHEN...Until 11 AM PDT Saturday. * IMPACTS...Plan on slippery road conditions. The hazardous conditions could impact travel this evening through Saturday morning.

Winter Weather Advisory issued November 1 at 2:27PM PDT until November 2 at 11:00AM PDT by NWS Reno NV

* WHAT...Snow. Snow accumulations up to 2 inches below 7000 feet, and 2 and 6 inches with localized areas up to 8 inches above 7000 feet. Winds gusting as high as 60 mph over Sierra ridges. * WHERE...Greater Lake Tahoe Area. * WHEN...Until 11 AM PDT Saturday. * IMPACTS...Plan on slippery road conditions. The hazardous conditions could impact travel late this evening through Saturday morning. Gusty winds could bring down tree branches. * ADDITIONAL DETAILS...Gusty winds and waves up to 3 feet may lead to hazardous boating conditions on Lake Tahoe.