After issuing a severe thunderstorm warning that lasted until 12:15 p.m. Tuesday, the National Weather Service extended a flash flood warning from 1 to 3 p.m. for Westhampton and points east.
Already 2 to 4 inches of rain had been detected in the area, the service said at just before 1 p.m., with another possible 1 to 2 inches through 3 p.m.
The thunderstorm warning, issued at 11:34 a.m. had indicated that the storm was "capable of producing quarter-sized hail and damaging winds in excess of 60 mph," already with "cloud-to-ground lightning occurring." Among the locations mentioned were Westhampton, Shinnecock Hills, Southampton, Bridgehampton and East Hampton.
Already heavy rain hit Long Island earlier Tuesday, with a pattern of storms spreading across the Nassau-Suffolk border during the morning commute.
The National Weather Service issued a special weather statement shortly after 10 a.m., saying it was tracking a series of strong storms "that will continue to impact the south shore of Suffolk County."
The storms were seen near Islip and were moving eastward at about 20 mph toward the Hamptons, the service said.
Earlier, the service had issued a severe thunderstorm warning for portions of both counties until 8 a.m. In issuing the warning, the service said that just after 7 a.m. "Doppler radar indicated a severe thunderstorm capable of producing quarter-size hail . . . and damaging winds in excess of 60 mph," the service said.
The service also said patches of dense fog will remain until about 10 a.m.
Suffolk police reported a tree down in Copiague, on Bayview Avenue, and a driver stuck in a puddle in a parking lot in Holtsville.
Nassau police reported nothing unusual related to rain.
Meteorologist Joe Pollina of the Upton-based service said it was too early to tell if the storm produced the hail and excess winds, but indicated that by early Tuesday afternoon the storm should give way to clear and dry weather.
"At least for a portion of today [Tuesday] we'll see showers and thunderstorms, probably through the late morning," Pollina said. "Then the chances of raindrop off in the early afternoon. By mid afternoon, we should be on the dry side.
The service issued a flash warning for southeastern Suffolk until 1 p.m. and a flood advisory until 12:30 p.m.; earlier, an urban flood advisory was issued for southeastern Nassau until 8:30 a.m. and for Suffolk until 10:30 a.m.
The service said storm runoff could cause flooding of urban areas -- highways, streets and underpasses as well as other drainage areas and low-lying spots.
In an early morning update, the service said the storm appeared near Freeport and was moving northeast at 35 mph, the service said.
Heavy rain scattered across Long Island from the Meadowbrook State Parkway in Nassau to Route 110 in Melville, according to reports.
Other locations in the warning include, but aren't limited to, Wantagh, Massapequa, Levittown, Amityville, Gilgo state park, Farmingdale, Lindenhurst, Melville, Babylon, Captree state park, Deer Park, Dix Hills, Bay Shore, Islip, Brentwood, Commack, Hauppauge, Smithtown, Sayville, Ronkonkoma and Holbrook.
In addition to large hail and damaging winds, the weather service said "continuous cloud-to-ground lightning is occurring with this storm" and advised those who hear thunder to move indoors.
After Tuesday's rain, the rest of the week should be clear and mostly sunny, the service said. There is a slight chance or rain Thursday, but most of the week should provide daily highs into the 80s and nightly lows in the 50s and 60s.
With Patricia Kitchen