This story has been updated.
WESTCHESTER COUNTY, N.Y. -- A Severe Thunderstorm Warning was issued for much of the area, including Westchester County, early Thursday evening.
A Severe Thunderstorm Watch, meaning there is a possibility of a thunderstorm, went into effect at 2:30 p.m., lasting until 10 p.m. It was upgraded to a Severe Thunderstorm Warning, meaning a thunderstorm is likely, at 6:43 p.m.
Very heavy rain, winds up to 40 miles per hour with hail up to nickel size, and cloud to ground lightning is occurring with this storm, the National Weather Service reports.
Lightning is one of nature's No. 1 killers, warns the National Weather Service, adding, "If you hear thunder, you are close enough to be struck by lightning. Move inside to safe shelter immediately."
A Flash Flood Watch for Westchester was issued at 8 a.m. Thursday and lasts until noon on Friday.
After the damp start to the Holiday Weekend, it is expected to brighten up, starting late Friday and lasting through the weekend. For a look at the weekend forecast, click here .