San Mateo County, CA
Alerts
Alerts are listed in order of start time and level of severity. Click on the alert title to read details for each alert.
In effect from Thursday 06/11 12:00 PM PDT – Thursday 06/11 11:00 PM PDT
Issued by NWS San Francisco CA
What
High temperatures between 90 and 103 for interior valleys and higher elevations. High temperatures between 85 and 96 degrees for the Bay Shoreline.
Where
North Bay Interior Mountains and Valleys, and San Francisco Bay Shoreline.
When
From noon to 11 PM PDT Thursday.
Impacts
This level of heat affects most individuals sensitive to heat, especially those without effective cooling and/or adequate hydration. Impacts possible in some health systems and in heat-sensitive industries.
What to Do
Hydration is a critical piece to surviving the heat. Drink water, and if possible, take water to those who are vulnerable.
Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to the early morning or evening. Take action when you experience symptoms of heat exhaustion and/or heat stroke.
Beat the heat and check the backseat! Do not leave young children or pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes.
Areas Impacted
- Sonoma Coastal Range
- North Bay Interior Mountains
- North Bay Interior Valleys
- San Francisco Bay Shoreline
Tips to Stay Safe
A Heat Advisory means dangerous heat conditions are happening now or soon. Take action before, during and after the heat to stay safe.
- Stay in air-conditioned spaces if possible. Find cooling centers or places with AC in your community that you can go to, like libraries or shopping malls.
- Stay hydrated and stock up on clean drinking water to get you through multiple days of heat.
- Reschedule outdoor activities for cooler times of the day, and take breaks in the shade or air conditioning.
- Cover windows with curtains or shades, or use window reflectors designed to reflect heat back outside.
- Check on friends, family, and neighbors, especially those who do not have air conditioning or spend much of their time alone.
Make sure you know the signs of heat-related illness and how to respond.
In effect from Thursday 06/11 7:00 PM PDT – Wednesday 06/17 3:00 AM PDT
Issued by NWS San Francisco CA
What
Up to 1.5 ft of inundation above ground level is possible in low-lying areas near shorelines and tidal waterways.
Where
Bayshore regions near the San Francisco Bay.
When
From 7 PM Thursday to 3 AM PDT Wednesday.
Impacts
Flooding of lots, parks, and roads with only isolated road closures expected.
Additional Details
At the San Francisco tidal gauge, high tide is expected to be 1.2 ft above normal (6.98 ft MLLW) at 8:51 PM on Thursday the 11th, 1.5 ft above normal (7.33 ft MLLW) at 9:34 PM on Friday the 12th, 1.8 ft above normal (7.58 ft MLLW) at 10:20 PM on Saturday the 13th, 1.3 ft above normal (7.10 ft MLLW) at 11:10 PM on Sunday the 14th, 1.2 ft above normal (7.05 ft MLLW) at 12:02 AM on Tuesday the 16th, and 1.0 ft above normal (6.81 ft MLLW) at 12:56 AM on Wednesday the 17th. High tide varies up to 90 minutes earlier or later along the Pacific Coast and through the San Francisco Bay, respectively.
What to Do
If travel is required, allow extra time as some roads may be closed. Do not drive around barricades or through water of unknown depth. Take the necessary actions to protect flood-prone property.
Areas Impacted
- San Francisco
- San Francisco Bay Shoreline
Tips to Stay Safe
A Flood Advisory is issued when flooding may cause significant inconvenience, or even become dangerous if you are not careful. Know your risk at home, work and school, and use caution when flooding is expected.
- Be aware of low-lying areas along your travel routes that are most likely to flood.
- Check road conditions before traveling, and obey road closures and barricades.
- Never walk, swim, or drive through flood waters.
- Stay tuned for local weather updates on the situation as it develops.
In effect from Thursday 06/11 12:59 AM PDT – Thursday 06/11 9:00 PM PDT
Issued by NWS San Francisco CA
What
Increased risk of sneaker waves and strong rip currents due to long period southerly swell.
Where
Pacific Coast beaches, especially south and southwest facing beaches, across Sonoma, Marin, San Mateo, and Santa Cruz Counties.
When
Through 9 PM Thursday evening.
Impacts
Dangerous swimming and surfing conditions and localized beach erosion can be expected. Sneaker waves can sweep across the shoreline without warning, pulling people into the sea from rocks, jetties and beaches.
What to Do
Stay off of jetties, piers, rocks, and other waterside infrastructure. Remain out of the water to avoid hazardous surf and NEVER turn your back on the ocean. Monitor local weather, surf and tide forecasts at www.weather.gov/mtr.
Areas Impacted
- Coastal North Bay Including Point Reyes National Seashore
- San Francisco Peninsula Coast
- Northern Monterey Bay
Tips to Stay Safe
Your area may see dangerous swimming conditions. Use caution:
- Stay off of rocks and jetties due to dangerous conditions
- Stay out of the water to avoid hazardous swimming conditions, and stay near occupied lifeguard towers
- Keep small children in sight and within arm’s reach at all times.
Briefings
From the Forecaster
Hot Thursday-Friday
Created by the NWS San Francisco WFO
Widespread Moderate HeatRisk is anticipated on Thursday and Friday across a good portion of the Bay Area. Moderate Heatrisk means members of heat-sensitive groups will experience negative heat-related health effects, including heat illnesses. Be sure to drink plenty of water, do not leave children or pets in unattended vehicles. Take frequent breaks in air conditions (if applicable) or shade. Shift activities outdoors to cooler times of day.
Seven-day Weather Risk Overview
The graphic shows the daily risk summary for 7 days. Daily risk is based on highest risk factor for that day.
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