Long Island weather forecast: Thunderstorms expected as state issues air quality advisory

High temperatures in the mid-80s were expected to give way to showers lasting overnight Friday until about 2 a.m. Saturday. The storms were forecast to reach Nassau County and Western Suffolk County on Friday evening, totaling about a half-inch of rain. 

A special weather statement warning of storms, with possible high wind gusts was forecast in Manhattan and the Bronx through 7 p.m., as the storms tracked east toward Long Island. 

Showers and thunderstorms are expected to continue and intensify Friday night, bringing winds and up to three-quarters-of-an-inch of rain, according to the National Weather Service.

In a hazardous weather outlook statement issued Friday, the weather service said: “Showers and thunderstorms are expected to develop ahead of a cold front and move through the region this afternoon and evening. Some thunderstorms could be strong to severe, capable of producing gusty to damaging winds, large hail and brief heavy downpours. Localized flash flooding is possible.”

Humidity levels topped 70% Friday afternoon, with high temperatures reaching 86 degrees in some inland parts of Long Island. Overnight lows were expected to dip into the mid-60s.

The storms are expected to clear for the upcoming Father’s Day weekend figure to borderline on spectacular. The weather service is calling for sunny skies both Saturday and Sunday with highs right around 80 degrees.

An Air Quality Alert from New York State was in effect Friday through 11 p.m., including for Nassau and Suffolk counties. Officials warned of high ozone levels that are unhealthy for sensitive groups.
People with lung disease such as asthma, children and teens, older adults, and people who are routinely active outdoors for six or more hours a day should reduce exposure outside and avoid strenuous activities, the advisory states. 

There was also a warning for “dangerous” and potentially life-threatening rip currents at South Shore ocean beaches — and for a series of severe late-afternoon thunderstorms that meteorologists said could deluge Long Island and cause localized flash flooding.

The weather service issued a warning for all South Shore ocean beaches from Queens to Suffolk, advising beachgoers: “Life-threatening rip currents are likely for all people entering the surf zone. Anyone visiting the beaches should stay out of the surf. Rip currents can sweep even the best swimmers away from shore into deeper water … If you enter the surf zone, always have a flotation device with you and swim near a lifeguard. If caught in a rip current, relax and float, and do not swim against the current. If able, swim in a direction following the shoreline.

“If unable to escape, face the shore and yell or wave for help.”

All this weather-related drama comes amid what figures to be a wild week for weather across Long Island.

That, because the weather service also is predicting a potential for the first heat wave of the season to start Tuesday, when peak heat index values above 95 are possible.

The heat index is based on a combination of actual temperature and humidity — and how that combination affects the comfort level for humans.

A combination of the two between 90 and 103 is considered a zone of “extreme caution” for anyone who plans to be outdoors or who has preexisting conditions that make them vulnerable or susceptible to extreme heat conditions. This includes young children, seniors and those with respiratory or heart conditions.

The weather service is predicting temperatures in the high 80s on Tuesday, with temperatures approaching 90 degrees on Wednesday, Juneteenth — and reaching 91 on Thursday.

It is all part of a high-pressure system known as a “heat dome” expected to trap a mass of hot temperatures and humidity over the Northeast through most of next week, the weather service said.

With John Valenti

By John Asbury

john.asbury@newsday.comJohnAsbury

John Asbury is a breaking news and general assignment reporter. He has been with Newsday since 2014 and previously worked at The Press-Enterprise in Riverside, California.