Oppressive heat that baked Long Island over the weekend finally, mercifully let up Sunday night. In its place Monday, possible gusty winds and thunderstorms, with the heaviest rain probably arriving in the late afternoon and continuing into the night, the National Weather Service said.
Sunday's excessive heat warning led to temperatures into the high 90s with a heat index of 110 degrees when considering humidity, the weather service said. Even so, Sunday's high of 99 degrees at Long Island MacArthur Airport, which had fallen to 88 by 8:30 p.m., didn't break the Long Island record for July 21 — 101 in 1991. The hottest day on record for Long Island was 104 degrees on July 3, 1966, according to the weather service's Upton office.
The weather service issues an excessive heat warning when the combination of heat and humidity is expected to make it feel like it’s 105 degrees or hotter.
The heat will break in a big way Monday with a 60 percent chance of showers and thunderstorms throughout the day and heavier downpours for the evening commute. The high Monday is expected to hit 82 with a low of 69, forecasters said, with a tenth to a quarter of an inch possible.
Tuesday will see the thermometer plunge even more with highs across much of Long Island only topping out in the low 70s and an 80 percent chance of heavy rain before noon. The low Tuesday is expected to drop to 64 degrees, the weather service said. After that, temperatures through Saturday are expected to return to seasonal averages with highs in the low to mid 80s and lows of about 70 degrees. Clear skies are forecast through the weekend.