Long Island weather: Heavy downpours, thunderstorms expected; tornadoes possible

Parts of Long Island may see multiple rounds of heavy downpours and thunderstorms Tuesday, as the National Weather Service forecasts scattered instances of flash flooding and dangerous winds strong enough to cause localized tornadoes in the tristate area.

Meteorologist Brian Ciemnecki said while showers could begin as early as late morning on Tuesday, chances of thunderstorms will increase throughout the day. The highest chance of severe storms will be Tuesday evening, he said.

Long Island can expect up to three quarters to an inch of total rainfall on Tuesday, but localized thunderstorms may produce heavier and higher amounts.

The weather service issued a hazardous weather outlook for the northern part of Long Island due to the potential for flash flooding, the weather service said.

When thunderstorms are severe, they can produce wind gusts as high as 60 mph, which can potentially cause localized tornadoes. Tuesday should see highs in the upper 70s.

In an early briefing on Tuesday the National Oceanic and Atmospheric Administration forecast a Level 1 marginal risk for severe thunderstorm outlooks for Western Suffolk and the East End and a Level 2 slight risk for New York City and Nassau County.

Ciemnecki said we shouldn’t be scrambling to bunk in tornado shelters — at least on Long Island. The strongest chance of tornadoes in the tristate state area will be in New Jersey, which is under a Level 3, or enhanced chance, according to the NOAA map.

"As you get further east, those chances for the isolated tornadoes diminish, but there's still a threat for a potential tornado," Ciemnecki said. "I'm not saying somewhere on the island is going to get one. I'm just saying we can't rule that threat out."

The same sentiment applies to NOAA’s severe winds prediction map issued for Tuesday, where New Jersey will see wind gusts up to 75 mph but "kind of scales down a bit" as you travel past New York City and Long Island, he said.

In the "worst of it," Long Island should experience wind gusts between 40 to 50 mph, Ciemnecki said.

The service also forecasts dangerous rip currents at all ocean beaches Tuesday through 8 p.m. Wednesday.

"If you're out at the area beaches ... obviously you only want to swim with a lifeguard on duty and be extra very careful," Ciemnecki said.

Scattered showers may linger into Wednesday, but conditions should clear up by morning with highs in the mid-80s.

"It's probably going to be more dry than wet tomorrow," he said.

Check back for updates on this developing story.