Long Island weather: Sunny and mild weekend; stormy weather coming

Saturday and Sunday’s delightful weather — sunshine and daytime highs in the mid-50s are expected — is the equivalent of fool’s gold as Monday, the last day of the Atlantic hurricane season, may see a powerful storm.

Wind gusts as high as 70 mph are possible, the National Weather Service's Islip office said. The lowest category of hurricane, Category I, has a minimum wind speed just four mph faster, or 74 mph.

A hazardous weather outlook was issued for Monday, when one to two inches of rain are forecast, and on into that night, when another half an inch of rain may fall. Those rainfall totals may cause minor coastal flooding, according to the weather service.

Yet, the weather service advised, "If the storm system tracks further west, there could be heavier rainfall amounts and a more significant flood threat."

The timing of the winds may be favorable in dampening floods.

"The current modeling suggests only minor (beach erosion) right now, as the peak winds are lining up with the lower of two astronomical high tide cycles," the weather service said.

Pinning the coming storm on a deepening low pressure system, the weather service said: "Depending on the ultimate track and intensity of the system, gusts of 50 to 70 mph will be possible, with the strongest winds across Long Island and eastern Connecticut."

Gale-force winds will translate into high seas topping 10 feet, the weather service said.

"Winds then decrease all waters on Tuesday, but seas will remain high on the ocean," the weather service said.

On land, however, Tuesday will see a return to fine weather, with clear skies and a daytime high of 55 degrees expected.

The Wednesday to Friday stretch should offer more of the same, though daytime temperatures will slip closer to 50 degrees and nighttime thermometers will hover just above freezing, the forecasters said.

That is because, the weather service says, "A broad area of high pressure is modeled for the rest of the week so fair weather has been forecast at this time."