Thunderstorms and Heavy Rainfall in the Plains; Hazardous Heat in the South and Southeast

Severe thunderstorms will be possible across the northern/central Plains through Tuesday afternoon and from the central Plains to the Mid-Mississippi Valley Tuesday evening through Wednesday morning. Storms may produce large hail and damaging wind gusts, and heavy rainfall may lead to scattered instances of flash flooding. Meanwhile, hazardous heat persists across the South and Southeast. Read More >

Current conditions at

LOS ALTOS (LOAC1)

Lat: 37.35472°NLon: 122.14167°WElev: 539.0ft.

NA

60°F

16°C

Humidity 88%
Wind Speed E 1 MPH
Barometer NA
Dewpoint 56°F (13°C)
Visibility NA
Last update 17 Aug 10:10 PM PDT
Extended Forecast for

Portola Valley CA

  • Tonight

    Tonight: Patchy fog after 5am.  Otherwise, mostly cloudy, with a low around 54. Calm wind.

    Low: 54 °F

    Patchy Fog

  • Tuesday

    Tuesday: Patchy fog before 8am.  Otherwise, mostly cloudy through mid morning, then gradual clearing, with a high near 86. Calm wind becoming north around 5 mph in the afternoon.

    High: 86 °F

    Patchy Fog
    then Sunny

  • Tuesday Night

    Tuesday Night: Patchy fog between 2am and 3am.  Otherwise, partly cloudy, with a low around 55. Light west southwest wind.

    Low: 55 °F

    Partly Cloudy
    then Patchy
    Fog

  • Wednesday

    Wednesday: Patchy fog before 8am.  Otherwise, mostly sunny, with a high near 83. Light and variable wind.

    High: 83 °F

    Patchy Fog
    then Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 55. West northwest wind around 5 mph becoming calm  in the evening.

    Low: 55 °F

    Partly Cloudy

  • Thursday

    Thursday: Partly sunny, with a high near 81.

    High: 81 °F

    Partly Sunny

  • Thursday Night

    Thursday Night: Mostly cloudy, with a low around 55.

    Low: 55 °F

    Mostly Cloudy

  • Friday

    Friday: Mostly sunny, with a high near 77.

    High: 77 °F

    Mostly Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 53.

    Low: 53 °F

    Mostly Clear

Detailed Forecast

Tonight
Patchy fog after 5am. Otherwise, mostly cloudy, with a low around 54. Calm wind.
Tuesday
Patchy fog before 8am. Otherwise, mostly cloudy through mid morning, then gradual clearing, with a high near 86. Calm wind becoming north around 5 mph in the afternoon.
Tuesday Night
Patchy fog between 2am and 3am. Otherwise, partly cloudy, with a low around 55. Light west southwest wind.
Wednesday
Patchy fog before 8am. Otherwise, mostly sunny, with a high near 83. Light and variable wind.
Wednesday Night
Partly cloudy, with a low around 55. West northwest wind around 5 mph becoming calm in the evening.
Thursday
Partly sunny, with a high near 81.
Thursday Night
Mostly cloudy, with a low around 55.
Friday
Mostly sunny, with a high near 77.
Friday Night
Mostly clear, with a low around 53.
Saturday
Mostly sunny, with a high near 78.
Saturday Night
Mostly clear, with a low around 54.
Sunday
Mostly sunny, with a high near 78.
Sunday Night
Patchy fog. Otherwise, partly cloudy, with a low around 54.
Monday
Patchy fog. Otherwise, mostly sunny, with a high near 76.
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ABOUT THIS FORECAST

 
Point Forecast:
Portola Valley CA
 37.39°N 122.23°W (Elev. 397 ft)
10:12 pm PDT Aug 17, 2026
11pm PDT Aug 17, 2026-6pm PDT Aug 24, 2026
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database