Severe weather, including thunderstorms and flash flooding, could impact the Lehigh Valley Sunday evening.
According to the National Weather Service in Mount Holly, New Jersey, the Lehigh Valley area is at a “slight risk” of excessive rainfall leading to flash flooding from 7 p.m. to 2 a.m.
The threat for flooding has decreased slightly over most of the area, but there remains at least some threat across the region with multiple rounds of showers and storms expected today and tonight. For the latest radar visit https://t.co/m3Lzl7udXz pic.twitter.com/9Pckym9YDc
— NWS Mount Holly (@NWS_MountHolly) August 16, 2026
Thunderstorms could impact the area as soon as 2 p.m.; the chance of rainfall is 80%, with rainfall totals between quarter to a half an inch possible on Sunday.
Overnight, another quarter to half an inch of rain could fall as well as thunderstorms before 3 a.m.
The wet weather comes amid improving drought conditions across the Lehigh Valley area after significant rainfall earlier this month.
Here is the extended forecast for the Allentown area.
Today: A chance of showers, then showers and possibly a thunderstorm after 2 p.m. High near 79. South wind 5 to 10 mph. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
Tonight: Showers and possibly a thunderstorm before 3 a.m., then a chance of showers and thunderstorms, mainly between 3 and 5 a.m. Patchy fog after 11 p.m. Low around 67. Southeast wind 5 to 10 mph. Chance of precipitation is 90%. New rainfall amounts between a quarter and half of an inch possible.
Monday: A slight chance of showers, then a chance of showers and thunderstorms after 2 p.m. Cloudy, then gradually becoming mostly sunny, with a high near 87. Calm wind becoming northwest around 5 mph in the afternoon. Chance of precipitation is 40%. New rainfall amounts of less than a 10th of an inch, except higher amounts possible in thunderstorms.
Monday night: A chance of showers and thunderstorms before 8 p.m. Partly cloudy, with a low around 66. Northwest wind around 5 mph becoming calm. Chance of precipitation is 30%. New precipitation amounts of less than a 10th of an inch, except higher amounts possible in thunderstorms.
Tuesday: Sunny, with a high near 86. Calm wind becoming northwest around 5 mph in the afternoon.
Tuesday night: Mostly clear, with a low around 63.
Wednesday: Sunny, with a high near 86.
Wednesday night: A chance of showers after 2 a.m. Partly cloudy, with a low around 66. Chance of precipitation is 50%.
Thursday: A chance of showers before 2 p.m. Partly sunny, with a high near 83. Chance of precipitation is 30%.
Friday: Mostly sunny, with a high near 82.
Saturday: A chance of showers. Partly sunny, with a high near 82. Chance of precipitation is 30%.