Parts of Long Island got another dose of heavy rain and flooding Wednesday, but although chances for a tornado like the one that touched down last week in central Suffolk County remain slim, the National Weather Service forecasts more thunderstorms Wednesday evening into Thursday morning.
Just after 12 p.m., the service had issued a severe thunderstorm warning lasting until 1 p.m. for eastern Nassau County and until 1:15 p.m. for Suffolk County, both of which have expired. An earlier warning for Nassau County and western Suffolk County expired at 12:15 p.m. The storms were capable of producing quarter-size hail and damaging winds in excess of 60 mph, the warning said.
The Upton-based service also issued a flash-flood warning until 3:15 p.m. for western Nassau County. An earlier warning expired at 12:45 p.m. Rainfall rates of 1 inch to 11/2 inches per hour are possible, and excessive runoff from rain could cause flooding of small creeks and streams, roadways and other low-lying spots, the service said.
Nassau County police issued a travel advisory to motorists shortly after noon, warning that "periodic intense downfalls of rain are causing flooding and accumulating pooling of water along roadways." Motorists should not try to drive through standing water, police said in the advisory.
The Village of Westbury also reported serious flooding in many neighborhoods and loss of power because of heavy rain and lightning.
The Long Island Rail Road reported on its website that service was restored in both directions between Hicksville and Jamaica on the Port Jefferson / Huntington and Ronkonkoma branches with delays up to 90 minutes. Service on the mainline was affected earlier by weather-related signal problems and heavy flooding. LIRR personnel have reduced the water level in these areas, the railroad said.
Morrin said a tornado can't be counted out 100 percent with any such storm at this time of year. Heavy rain, high humidity and lightning often can bring high winds -- gusts of 58 mph or more, he said.
But the Storm Prediction Center in Norman, Okla., whose job is to track tornadoes, says the East and Long Island have less than a 2 percent chance for "tornadic activity," Morrin said.
The chances for storm-related winds of 58 mph or higher and hail are about 15 percent, Morring said, citing the Storm Prediction Center's forecast.
A lingering low-pressure trough was to bring rain in the late morning and again later Wednesday, the service said. And with the evening rain, a slight chance for scattered downpours, lightning and gusty winds is in the forecast, said Tim Morrin, a meteorologist with the service.
The chance of rain for the rest of Wednesday is between 30 percent and 60 percent, the service said.
The low-pressure trough is expected to move away later Wednesday night, bringing clear skies and a drop in humidity.
Then, late Friday, a slow-moving cold front combines with a low-pressure system to shower the East and most of Long Island with another round of scattered rain.
Chances for precipitation from late afternoon Friday until Sunday night range from 30 to 50 percent, the service said.
Morrin said the weekend most likely will be partly sunny skies, moderate to high humidity levels "with some thunderstorms that could crop up."
Last Friday, a fast-moving tornado touched down in central Suffolk, creating the most havoc in Bohemia, where trees were thrown into power lines, homes and cars, the service said.
The twister stayed on the ground for about eight minutes, covering 4 1/2 miles, the service said. Police reported no injuries.