Dangerous Heat in the Southwest; Severe Thunderstorms and Heavy Rain in the Northeast and Mid-Atlantic

Dangerous heat will persist across the Southwest U.S. through Friday with daytime highs of 110-115°F. Heat across the southern Plains will briefly ease to near-normal by late week. Strong to severe thunderstorms may produce damaging wind, hail, a tornado or two, heavy rain and flash flooding across parts of the Mid-Atlantic and Northeast. Heavy rainfall threat continues across the Gulf Coast. Read More >

Current conditions at

Chester County Airport (KMQS)

Lat: 39.98°NLon: 75.87°WElev: 659ft.

Overcast

71°F

22°C

Humidity 96%
Wind Speed Vrbl 5 mph
Barometer 30.02 in
Dewpoint 70°F (21°C)
Visibility 10.00 mi
Last update 27 Aug 8:35 am EDT
Extended Forecast for

Lionville-Marchwood PA

Flood Watch August 27, 12:00pm until August 28, 04:00am
Click here for hazard details and duration
Flood Watch
  • Today

    Today: Showers and thunderstorms before 4pm, then showers likely and possibly a thunderstorm between 4pm and 5pm, then a chance of showers and thunderstorms after 5pm.  High near 84. South wind 5 to 10 mph.  Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    High: 84 °F

    Showers

  • Tonight

    Tonight: Showers and thunderstorms likely before 2am, then a slight chance of showers.  Patchy fog after 3am.  Otherwise, mostly cloudy, with a low around 66. South wind around 5 mph becoming calm  in the evening.  Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

    Low: 66 °F

    Showers
    Likely and
    Patchy Fog

  • Friday

    Friday: A slight chance of showers, then a chance of showers and thunderstorms after 3pm.  Patchy fog before 8am.  Otherwise, partly sunny, with a high near 83. Calm wind becoming north around 5 mph.  Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 83 °F

    Patchy Fog
    then Chance
    Showers

  • Friday Night

    Friday Night: A chance of showers and thunderstorms, mainly before 7pm.  Partly cloudy, with a low around 64. Calm wind.  Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 64 °F

    Chance
    Showers then
    Partly Cloudy

  • Saturday

    Saturday: Mostly sunny, with a high near 84. North wind around 5 mph.

    High: 84 °F

    Mostly Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 65.

    Low: 65 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 85.

    High: 85 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 69.

    Low: 69 °F

    Partly Cloudy

  • Monday

    Monday: Mostly sunny, with a high near 88.

    High: 88 °F

    Mostly Sunny

Detailed Forecast

Today
Showers and thunderstorms before 4pm, then showers likely and possibly a thunderstorm between 4pm and 5pm, then a chance of showers and thunderstorms after 5pm. High near 84. South wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Tonight
Showers and thunderstorms likely before 2am, then a slight chance of showers. Patchy fog after 3am. Otherwise, mostly cloudy, with a low around 66. South wind around 5 mph becoming calm in the evening. Chance of precipitation is 60%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
Friday
A slight chance of showers, then a chance of showers and thunderstorms after 3pm. Patchy fog before 8am. Otherwise, partly sunny, with a high near 83. Calm wind becoming north around 5 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Friday Night
A chance of showers and thunderstorms, mainly before 7pm. Partly cloudy, with a low around 64. Calm wind. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Saturday
Mostly sunny, with a high near 84. North wind around 5 mph.
Saturday Night
Mostly clear, with a low around 65.
Sunday
Mostly sunny, with a high near 85.
Sunday Night
Partly cloudy, with a low around 69.
Monday
Mostly sunny, with a high near 88.
Monday Night
Mostly cloudy, with a low around 69.
Tuesday
Mostly sunny, with a high near 87.
Tuesday Night
A chance of showers. Partly cloudy, with a low around 69. Chance of precipitation is 30%.
Wednesday
A chance of showers. Partly sunny, with a high near 86. Chance of precipitation is 30%.
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ABOUT THIS FORECAST

 
Point Forecast:
Lionville-Marchwood PA
 40.05°N 75.63°W (Elev. 479 ft)
4:09 am EDT Aug 27, 2026
8am EDT Aug 27, 2026-6pm EDT Sep 2, 2026
 
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Additional Resources

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Hourly Weather Forecast

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