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Tropical Storm Arthur and Heavy Rainfall in the South; Severe Weather in the Midwest

An outbreak of severe thunderstorms is expected across portions of Illinois and Indiana tonight. Intense tornadoes, swaths of damaging gusts, and hail in excess of 2 inches in diameter possible. Tropical Storm Arthur will continue to produce strong winds across coastal Upper Texas and Louisiana tonight, as well as potentially life-threatening flooding across southern Louisiana into Mississippi. Read More >

Current conditions at

Allentown, Lehigh Valley International Airport (KABE)

Lat: 40.65°NLon: 75.45°WElev: 384ft.

Overcast

73°F

23°C

Humidity 79%
Wind Speed SW 7 mph
Barometer 29.63 in (1003.0 mb)
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 18 Jun 7:51 am EDT
Extended Forecast for

Mertztown PA

  • Today

    Today: Showers and thunderstorms likely, mainly before noon. Mostly cloudy, then gradually becoming sunny, with a high near 86. Breezy, with a southwest wind 10 to 15 mph increasing to 15 to 20 mph in the afternoon. Winds could gust as high as 35 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 86 °F

    Showers
    Likely then
    Slight Chance
    T-storms and
    Breezy

  • Tonight

    Tonight: Increasing clouds, with a low around 63. West wind 10 to 15 mph, with gusts as high as 25 mph.

    Low: 63 °F

    Increasing
    Clouds

  • Juneteenth

    Juneteenth: Mostly cloudy through mid morning, then gradual clearing, with a high near 81. West wind 5 to 15 mph.

    High: 81 °F

    Becoming
    Sunny

  • Friday Night

    Friday Night: Clear, with a low around 59. West wind around 10 mph.

    Low: 59 °F

    Clear

  • Saturday

    Saturday: Sunny, with a high near 80. West wind 10 to 15 mph.

    High: 80 °F

    Sunny

  • Saturday Night

    Saturday Night: Mostly clear, with a low around 58.

    Low: 58 °F

    Mostly Clear

  • Sunday

    Sunday: Mostly sunny, with a high near 81.

    High: 81 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.

    Low: 63 °F

    Chance
    Showers

  • Monday

    Monday: Showers, with thunderstorms also possible after 2pm. High near 77. Chance of precipitation is 80%.

    High: 77 °F

    Showers

Detailed Forecast

Today
Showers and thunderstorms likely, mainly before noon. Mostly cloudy, then gradually becoming sunny, with a high near 86. Breezy, with a southwest wind 10 to 15 mph increasing to 15 to 20 mph in the afternoon. Winds could gust as high as 35 mph. Chance of precipitation is 60%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Tonight
Increasing clouds, with a low around 63. West wind 10 to 15 mph, with gusts as high as 25 mph.
Juneteenth
Mostly cloudy through mid morning, then gradual clearing, with a high near 81. West wind 5 to 15 mph.
Friday Night
Clear, with a low around 59. West wind around 10 mph.
Saturday
Sunny, with a high near 80. West wind 10 to 15 mph.
Saturday Night
Mostly clear, with a low around 58.
Sunday
Mostly sunny, with a high near 81.
Sunday Night
A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.
Monday
Showers, with thunderstorms also possible after 2pm. High near 77. Chance of precipitation is 80%.
Monday Night
A chance of showers and thunderstorms before 8pm, then a chance of showers between 8pm and 2am. Mostly cloudy, with a low around 59. Chance of precipitation is 40%.
Tuesday
Mostly sunny, with a high near 79.
Tuesday Night
Mostly clear, with a low around 58.
Wednesday
Mostly sunny, with a high near 81.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Mertztown PA
 40.51°N 75.69°W (Elev. 499 ft)
Last Update:
4:08 am EDT Jun 18, 2026
Forecast Valid:
8am EDT Jun 18, 2026-6pm EDT Jun 24, 2026
 
Forecast Discussion
 
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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

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation