Long Island weather: Sunny, hot with more heat to come

It's going to be a hot week.

Sunday’s partly sunny skies will herald the start of a heat wave that will stretch into late in the week, the National Weather Service predicted.

While ocean breezes should temper how hot it gets on Long Island, the weather service said, "Heat index values on Sunday will rise to the middle to upper 90s, mainly across northeast New Jersey and portions of the Lower Hudson Valley, with isolated middle 90s across New York City and portions of the Lower Hudson Valley."

Heat and humidity will be especially strong for parts of New Jersey, with heat index values reaching as high as 104 through Thursday.

Long Island’s daytime high on Sunday is forecast to rise to about 83 degrees, and higher later in the week, but not as hot as elsewhere in the region.

Monday and Tuesday will be even hotter and muggy as well. Still, Long Island — thanks to coastal breezes — should once again be at least slightly cooler than its neighbors, with daytime temperatures topping out in the upper 80s.

The weather service warned: "Heat index values may reach the lower 100s across much of the forecast area, and heat advisories will likely be needed across the entire tristate (except for perhaps the Twin Forks of Long Island and southeastern New London) for Monday and Tuesday."

Long Island’s sultry weather, however, will fall far short of the unprecedented triple-digit temperatures now forecast for the Northwest by the weather service's Weather Prediction Center. And any showers Saturday on Long Island should be minor, unlike the severe storms predicted from the Southern Plains to the Great Lakes.

The high pressure system sitting over the western Atlantic Ocean is allowing heat and humidity to build in, as various fronts sweep through, the weather service explained. Clear skies typically result from high pressure systems as their falling air dries and cools.

Wednesday should also be sunny with a daytime high of 86 degrees, before clouds arrive that evening, the weather service said. The odds of showers and thunderstorms between 8 p.m. and 2 a.m. are 30%.

Thursday looks likely to alternate between sunny skies and downpours and thunderstorms, with the chances of precipitation at 40%. The high for the day should be a more moderate 83 degrees.

Friday’s forecast is quite similar except the odds of showers and storms are a bit higher — 50% — and the high for the day should be 81 degrees, the weather service said.