Widespread showers and thunderstorms have developed across much of the Mid-Atlantic and Northeastern states this afternoon. Heavy rain, gusty winds, and frequent lightning will all be possible later this evening/tonight for much of the NYC area!
Heat and humidity are expected to reach a relative peak today in the Mid-Atlantic and Northeast states, with rising dew points and temperatures leading to oppressive Heat Index values once again. The National Weather Service has extended the Heat Advisory (which was already in place) into Thursday evening, with Heat Index Values expected to rise near 100 F in many areas from New Jersey into the NYC Metro Area and Connecticut.
As you may be aware, the Heat Index value is a function of both temperature and dew point, and although temperatures will reach the lower 90’s later today the main story will be the dew points. They’ll rise well into the 70’s, which will leave the airmass feeling hot, thick and sticky. It will also be unstable as a result, and with a frontal boundary approaching during the afternoon, the instability will serve as fuel for the development of thunderstorms.
Strong and severe thunderstorms moved through parts of the Northeast states on Tuesday evening, producing frequent and dangerous lightning as well as strong, gusty winds and torrential rain. There was even a wall cloud spotted in Queens and Nassau counties, as an area of distinct rotation appeared on terminal doppler radar out of Kennedy Airport. This was the third instance of rotating thunderstorms in the NYC area in just over a week.
The threat for strong thunderstorms will continue today as a frontal boundary slowly sinks towards the region. Instability is expected to build once again by this afternoon across the Northern Mid-Atlantic States with ample heating and a continued source of moisture (you may have noticed that it is very humid outside). As better forcing for storm development approaches later today, thunderstorms are expected to increase in coverage once again.
Good morning! There is increasing potential for some heavy rainfall and strong to severe thunderstorms later this afternoon and evening, as a cold front approaches. Before that though, it will be just be hot and humid with high temperatures reaching the mid-upper 80s or lower 90s over the urban I-95 corridor, with more sunshine into at least early this afternoon. It will be a little cooler, with sea-breezes later, closer to the shore. But southerly winds will continuing to transport tropical moisture into the area, with dewpoints in the lower to middle 70s. This will lead to heat index values in the middle or upper 90s, again this afternoon. Thus a heat advisory continues for Northeast NJ and NYC for today.