Long Island forecast: Rainy Friday morning commute likely

Long Island’s Friday morning commute could be affected by a further bout of heavy rain, which, given earlier precipitation, could also mean road flooding just as people are heading to work, forecasters say.

"A small but very wet weather system will move across LI tomorrow morning,” said Bill Korbel, News 12 Long Island meteorologist. “Rain is likely to be heavy enough to cause some street flooding and that would make for a very slow morning commute.”

A flash flood watch has been issued for Nassau County for Friday from 4 a.m. to noon. The Island is looking at a forecast, as of late Thursday afternoon, of an inch to an inch and a half of rain, but rainfall totals could be higher in some spots, the National Weather Service said.

The heaviest rainfall looked to coincide with that go-to-work time frame from about an hour or two before sunrise to and hour or two after, when there also could be a rumble of thunder, said Tim Morrin, weather service meteorologist in Upton.

With rainfall of an inch an hour possible, he said, there could be “rapid ponding on roadways,” enhanced by faster run-off in some locations from surrounding terrain that was drenched by Tuesday’s system.

There remained some uncertainty late Thursday as to where the heaviest rain bands will set up, the weather service said, though it won’t “take much additional rainfall to cause flooding in locations hard hit on Tuesday.”

Among the unofficial rainfall amounts from Tuesday were: 4.27 inches in Port Jefferson Station; 4 inches in the Hauppauge area; 3.53 inches in Commack; 3.22 inches in the Kings Park area; 1.95 inches in Plainview; 1.92 inches in the North Wantagh area; and 1.75 inches in Syosset. Long Island MacArthur Airport recorded 1.29 inches of rain Tuesday and another  half-inch Wednesday, the weather service said.

Friday was also expected to see scattered showers in the afternoon, with temperatures warming up to the mid-60s.

The weekend, then, might be seen as a metaphorical rainbow, with Korbel describing it as being “sunny and mild, very pleasant.” Temperatures are expected to rise to the low 70s on Saturday and the upper 60s on Sunday, which marks the final day of September.