National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Heavy Rainfall Continues in Hawaii; Severe Thunderstorms and Heavy Rainfall in the Plains and Southern Appalachians

Areas of gusty winds, heavy rain leading to flash flooding, and high surf continue across portions of Hawaii as Tropical Storm Lala continues to move away from the islands. Severe thunderstorms and heavy rainfall will shift into the southern Appalachians today. Strong to severe thunderstorms may produce large hail, scattered wind gusts, and heavy rain today across the northern and central Plains. Read More >

Current conditions at

Allentown, Lehigh Valley International Airport (KABE)

Lat: 40.65°NLon: 75.45°WElev: 384ft.

Overcast

67°F

19°C

Humidity 97%
Wind Speed Calm
Barometer 29.88 in (1011.6 mb)
Dewpoint 66°F (19°C)
Visibility 9.00 mi
Last update 17 Aug 7:51 am EDT
Extended Forecast for

Mertztown PA

  • Today

    Today: A slight chance of showers between 2pm and 3pm, then a chance of showers and thunderstorms after 3pm. Patchy fog before 11am. Otherwise, partly sunny, with a high near 85. Calm wind becoming west around 5 mph in the afternoon. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    High: 85 °F

    Patchy Fog
    then Chance
    T-storms

  • Tonight

    Tonight: A chance of showers and thunderstorms, mainly before 7pm. Patchy fog after 9pm. Otherwise, mostly cloudy, with a low around 67. North wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

    Low: 67 °F

    Chance
    T-storms and
    Patchy Fog
    then Patchy
    Fog

  • Tuesday

    Tuesday: Patchy fog before 9am. Otherwise, sunny, with a high near 83. North wind around 5 mph.

    High: 83 °F

    Patchy Fog
    then Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 63. Northwest wind around 5 mph becoming calm.

    Low: 63 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 84. Light southwest wind becoming west 5 to 10 mph in the afternoon.

    High: 84 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Partly cloudy, with a low around 65.

    Low: 65 °F

    Partly Cloudy

  • Thursday

    Thursday: A chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 50%.

    High: 82 °F

    Partly Sunny
    then Chance
    T-storms

  • Thursday Night

    Thursday Night: A chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 62. Chance of precipitation is 30%.

    Low: 62 °F

    Chance
    T-storms then
    Partly Cloudy

  • Friday

    Friday: A chance of showers after 2pm. Mostly sunny, with a high near 81. Chance of precipitation is 30%.

    High: 81 °F

    Mostly Sunny
    then Chance
    Showers

Detailed Forecast

Today
A slight chance of showers between 2pm and 3pm, then a chance of showers and thunderstorms after 3pm. Patchy fog before 11am. Otherwise, partly sunny, with a high near 85. Calm wind becoming west around 5 mph in the afternoon. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Tonight
A chance of showers and thunderstorms, mainly before 7pm. Patchy fog after 9pm. Otherwise, mostly cloudy, with a low around 67. North wind around 5 mph. Chance of precipitation is 30%. New precipitation amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
Tuesday
Patchy fog before 9am. Otherwise, sunny, with a high near 83. North wind around 5 mph.
Tuesday Night
Mostly clear, with a low around 63. Northwest wind around 5 mph becoming calm.
Wednesday
Sunny, with a high near 84. Light southwest wind becoming west 5 to 10 mph in the afternoon.
Wednesday Night
Partly cloudy, with a low around 65.
Thursday
A chance of showers and thunderstorms after 2pm. Partly sunny, with a high near 82. Chance of precipitation is 50%.
Thursday Night
A chance of showers and thunderstorms before 8pm. Partly cloudy, with a low around 62. Chance of precipitation is 30%.
Friday
A chance of showers after 2pm. Mostly sunny, with a high near 81. Chance of precipitation is 30%.
Friday Night
A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 50%.
Saturday
A chance of showers. Partly sunny, with a high near 80. Chance of precipitation is 40%.
Saturday Night
A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 40%.
Sunday
A chance of showers. Partly sunny, with a high near 80. Chance of precipitation is 30%.
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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:
6:31 am EDT Aug 17, 2026
Forecast Valid:
8am EDT Aug 17, 2026-6pm EDT Aug 23, 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