As temperatures soar into the 90s and high humidity roasts the Seacoast, there's a few beaches to avoid when looking for a place to cool off.

The highest temperatures of the heat wave will be Wednesday and Thursday, with a Heat Advisory in effect until 8 p.m. Thursday night. Strong thunderstorms Thursday afternoon and evening will bring down the humidity, but temperatures will stay in the upper 80s and low 90s for Friday and through the weekend.

The Newburyport Health Department issued a public health warning Tuesday due to sewage overflow upstream just after midnight in Haverhill, Lowell, and Lawrence, which brings increased health risks.

Swimming in the river is discouraged at Moseley Woods, Cashman Park, Joppa Flats, and Plum Island.

Maximum Heat Index
Maximum Heat Index for July 20 (NWS)
loading...

An advisory continues at Pawtuckaway State Park Beach after several tests showed by the NH Department of Environmental Science came back with an unacceptable level of fecal bacteria. Samples taken July 12 and 14 also came back high.

Results from samples taken Wednesday will be available Thursday.

The advisories in both locations do not close the beaches.

Contact reporter Dan Alexander at Dan.Alexander@townsquaremedia.com or via Twitter @DanAlexanderNH