Long Island weather: Dangerous four-day heat wave begins Wednesday, with chance for storms each day

Stifling heat will settle over Long Island Wednesday and is expected to last into the Fourth of July weekend, with forecasters and local officials warning that heat indices in the 100s could make the stretch hazardous.

“This is potentially lethal,” Dr. Gregson H. Pigot, the Suffolk County health commissioner, told reporters at a briefing with county officials Tuesday at Smith Point County Park.

By Tuesday, when National Weather Service meteorologists put the metro area under an Extreme Heat Warning through Friday night, Long Island’s elected officials had announced that dozens of government buildings across the region would be readied as cooling centers. Gov. Kathy Hochul announced extended hours at state beaches. County Executives Bruce Blakeman and Ed Romaine warned their respective constituencies to curtail outdoor exposure and said residents without access to air conditioning should consider the cooling centers.

In scope and scale, the preparations resembled those for a blizzard. “In some ways, this is more life-threatening,” because of the risks posed by outdoor exertion, said Romaine, speaking at the news conference.

Widespread maximum heat indices, which combine high temperature with humidity, of 100 to 105 degrees are forecast for New York City and the northern and western suburbs Wednesday, with some areas reaching up to 110. Long Island maximum heat indices may be slightly lower, with 90s to close to 100 near the coast, the National Weather Service said.

Officials warned that days of sustained heat would also tax area infrastructure. MTA chair Janno Lieber said agency personnel would inspect tracks “through the heat to make sure the rails, which do sometimes kink in the heat, don’t get out of line.” They are also inspecting trains and cars to ensure they have working air conditioning and prepositioning generators in case of electrical outages, he said.

Hochul’s office, in a news release, warned that, as millions of state residents switch on air conditioners, electricity demand would surge, which could result in instances of “low voltage or isolated power outages.” The state record for such usage was set in 2013, when it reached 33,956 megawatts – enough to power nearly 34 million homes.

In an email, a PSEG Long Island representative said the utility had improved grid reliability by installing stronger poles and wires, among other measures. PSEG also has repair teams ready to work “around the clock” in case of power outages, the representative wrote. “High heat can place stress on electric equipment by causing transformers, cables and other components to operate at higher temperatures, which can increase the potential for equipment failure.”

The weather service issued an extreme heat warning for the city. Nassau and Suffolk remain under an extreme heat watch. The difference is a matter of degrees.

That forecast is expected to hold through Saturday, forecasters said.

Low temperatures across the region are not likely to drop below the upper 70s to the lower 80s Wednesday through Friday nights.

This level of rare, long-duration heat, with little to no overnight relief, will impact anyone without effective cooling and/or adequate hydration, the service said. There is a high risk of heat-related illness, such as heat exhaustion and heatstroke, especially those with underlying illness, the elderly or very young, performing strenuous outdoor activity

There is also a threat of severe thunderstorms for the entire week that could bring damaging winds, large hail and torrential downpours, the weather service said.

Check back for updates on this developing story.