Lehigh Valley under heat advisory as humidity will make it feel like 100 degrees; more storms possible

Friday is going to feel even worse than the Fourth of July did in the Lehigh Valley as humidity will make it feel like 100 degrees, with another round of showers and thunderstorms possible later in the day.

The National Weather Service has issued a heat advisory for the entire region, with heat index values forecast to reach as high as 104 degrees in some areas. The warning is in effect through 8 p.m. Saturday.

A hot air mass with a lot of moisture will remain in place over the region today, keeping dewpoints into the low and mid 70s and high temperatures in the low to mid 90s, according to the weather service forecast discussion. In addition to the excessive heat, this air mass will also create instability, increasing the risk of more thunderstorms.

Scattered thunderstorms are expected to develop late this afternoon and evening, according to the weather service.

There is a 50% chance of precipitation in the Lehigh Valley, with rainfall amounts of less than a tenth of an inch expected. Higher rainfall amounts are possible from any thunderstorms, according to the weather service.

Saturday’s forecast is shaping up to be a repeat of Friday, as the excessive heat advisory continues and there’s a chance for even more widespread thunderstorms, according to the weather service.

A round of heavy rain and thunderstorms moved through the Lehigh Valley on Thursday night, disrupting some of the region’s Fourth of July festivities and fireworks .

With the heat advisory, people are reminded to take precautions. If you must go outdoors, limit strenuous activities to the early morning and evening hours and wear lightweight and loose fitting clothing. Drink plenty of fluids, stay in an air-conditioned room and check up on relatives and neighbors.

Here is the extended weather service forecast for the region:

Saturday: A chance of showers, with thunderstorms also possible after 11 a.m. Patchy fog before 10 a.m. Otherwise, partly sunny, with a high near 92. Heat index values as high as 101. Calm wind becoming southwest around 5 mph in the afternoon. Chance of precipitation is 50%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Saturday Night: A chance of showers and thunderstorms, mainly before 11 p.m. Mostly cloudy, with a low around 71. South wind around 5 mph becoming calm. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.

Sunday: Partly sunny, with a high near 93. Calm wind becoming west around 5 mph.

Sunday Night: Partly cloudy, with a low around 70.

Monday: Partly sunny, with a high near 94.

Monday Night: Mostly cloudy, with a low around 71.

Tuesday: A chance of showers and thunderstorms after 2 p.m. Mostly cloudy, with a high near 91. Chance of precipitation is 50%.

Tuesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 71. Chance of precipitation is 50%.

Wednesday: A chance of showers and thunderstorms. Mostly cloudy, with a high near 88. Chance of precipitation is 50%.

Wednesday Night: A chance of showers and thunderstorms. Mostly cloudy, with a low around 68. Chance of precipitation is 40%.

Thursday: A chance of showers. Partly sunny, with a high near 87. Chance of precipitation is 30%.