Lehigh Valley under excessive heat warning through Wednesday morning as ‘dangerously hot conditions’ return

The Lehigh Valley will have another few days of “dangerously hot conditions,” as temperatures reach into the 90s again this week.

The National Weather Service placed the region under an excessive heat warning through Wednesday morning. Heat index values are expected to reach 102 degrees Monday and 104 on Tuesday. Lehigh and Northampton counties are under an excessive heat watch Wednesday as well.

Temperatures already have reached the 90s seven times this month, about half of the days so far this month, according to weather service data. Saturday, which had a recorded high of 91, was the most recent day to reach those temperatures.

Forecasters expect temperatures to be in the 90s Monday, Tuesday and Wednesday. Tuesday is expected to be the worst of the three days, with an anticipated high of 98.

The weather service recommends people stay in an air-conditioned room, stay out of the sun, and check up on relatives or neighbors. When outside, people should wear lightweight and loose-fitting clothes, the weather service said. Strenuous activities should be limited to the morning or evening.

Outside of the excessive heat, forecasters said there is a possibility of storms Monday through Wednesday. The region is under a marginal risk of severe weather Monday. There could be heavy downpours and damaging wind gusts of up to 60 mph.

Temperatures should be in the 80s Thursday through Saturday before returning to the 90s Sunday.

Here is the extended forecast from the National Weather Service:

Tuesday: A slight chance of showers and thunderstorms after 2 p.m. Sunny and hot, with a high near 98. Heat index values as high as 104. Light southwest wind increasing to 5 to 10 mph in the morning. Chance of precipitation is 20%.

Tuesday Night: A chance of showers and thunderstorms, mainly between 8 p.m. and 2 a.m. Partly cloudy, with a low around 75. Southwest wind around 5 mph becoming calm after midnight. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Wednesday: A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 2 p.m. High near 93. Light west wind increasing to 5 to 10 mph in the morning. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Wednesday Night: Showers and thunderstorms before 5 a.m., then a slight chance of showers. Low around 70. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Thursday: Mostly sunny, with a high near 85.

Thursday Night: Mostly clear, with a low around 62.

Friday: Sunny, with a high near 87.

Friday Night: Partly cloudy, with a low around 64.

Saturday: Mostly sunny, with a high near 87.

Saturday Night: Partly cloudy, with a low around 67.

Sunday: Mostly sunny, with a high near 90.