It's in effect until 11 p.m. Saturday, July 17. Damaging wind gusts in excess of 60 miles per hour are the main threat with any thunderstorm that becomes severe, the National Weather Service said in issuing the watch. Torrential downpours, frequent lightning, and flash flooding are all possible, along with quarter-size hail. A Flash Flood Watch remains in effect until Sunday morning, July 18. For a look at areas covered by the Severe Thunderstorm Watch (marked in yellow), check the image above. Of note, the watch includes Nassau County on Long Island but did not include Suffolk County when it was issued at 1 p.m. Saturday.