Evening thunderstorms possible for Nassau as high heat continues through Wednesday

Long Islanders should not expect relief from this week's high heat and humidity until Thursday, the National Weather Service in Upton said Tuesday.

The weather service has extended a heat advisory until Wednesday night for all of Long Island except the South Fork, and said the heat index will remain in the mid-90s for most parts of Long Island Wednesday, as it was on Tuesday.

"It will be much better on Thursday," Bryan Ramsey, a meteorologist at the National Weather Service, said. "Once we get to Thursday, the heat index drops to about 85."

Tuesday night, the weather service warned of the possibility of severe thunderstorms with heavy rain, hail and damaging winds for Nassau County until 10 p.m.

Isolated thunderstorms, with a higher chance for them closer to New York City, are also possible on Wednesday, as well as sizable hail, Ramsey said. 

On South Shore ocean beaches, Ramsey said, Wednesday will bring a high risk for rip currents. 

A heat advisory is issued when the combination of heat and humidity is expected to make it feel like it's between 95 and 99 degrees for two or more consecutive days — or, between 100 and 104 degrees for any length of time — the weather service said in a statement.

And while this week's heat has certainly been intense, Ramsey said it is not anything out of the norm for the summer months.

"We see these hotter outbreaks usually each summer month, particularly later in the summer," Ramsey said.

To help Long Islanders combat the heat, Nassau County has cooling centers available at the Cantiague Park administration office at 480 West John St. in Hicksville, the Wantagh Park administration building at 1 King Rd. in Wantagh, and the Mitchel Field administration building at 1 Charles Lindbergh Blvd. in Uniondale.

Suffolk, in addition to 91 official cooling centers available throughout the county, is providing support by opening Smith Point and Cupsogue Beach an additional hour, until 6:30 p.m., until further notice.

"Residents cannot be left high and dry in the heat wave," County Executive Ed Romaine said in a statement.

During the high heat, PSEG is also activating a thermostat program that shaves peak energy usage by relatively small amounts by raising the AC thermostats of around 40,000 volunteer customers.

PSEG enacted the program starting at 3:30 Tuesday afternoon by decreasing thermostats by around 3 degrees for 30 minutes to precool the homes before raising the thermostats 4 degrees from 4 p.m. to 7 p.m. Customers can override the system, but those who volunteer can get special discounts on their energy bills.

The Metropolitan Transportation Authority said it was also taking measures this week to protect Long Island commuters from the heat, and the potential service disruptions it could cause.

With Mark Harrington and Alfonso A. Castillo