New Risk Of Heavy Rain, Flash Flooding For The Hudson Valley

HUDSON VALLEY, NY — More storms are headed our way, and there's a risk of excessive rainfall again, so the National Weather Service has issued hazardous outlooks across the region.

"Important note to remember... is that with the flooding rains we received last weekend, some areas will be prone to flash flooding in a very short time. Orange County will be most susceptible, but all areas could experience flash flooding in a T-Storm with torrential downpours," said Bill Potter of Hudson Valley Weather.

To add insult to potential injury, New York State health and environmental officials issued an Air Quality Health Advisory for Westchester, Rockland, Putnam, Orange, Dutchess and Ulster counties for Thursday. The pollutant of concern is ozone and the advisory will be in effect through 11 p.m.

For Orange County, the NWS said there is a slight risk of severe thunderstorms in the afternoon through Thursday night. There is a marginal risk for flash flooding. Friday, the risk level is elevated to "slight" for flash flooding through Friday night, along with a marginal risk for severe thunderstorms.

The NWS issued a separate hazardous outlook with the same wording for Putnam, Rockland and Westchester counties: "Additional showers and thunderstorms are forecast through the weekend with flooding possible especially considering this area had previous flooding from last Sunday."

For Dutchess and Ulster counties, the NWS issued a hazardous outlook that extends to Sunday:

Showers and thunderstorms are possible late Thursday afternoon into evening. There is a marginal to slight risk for severe thunderstorms with main threat being damaging wind gusts and large hail. In addition, an isolated tornado or two can not be ruled out. Thunderstorm downpours could lead to flash flooding as well and the Weather Prediction Center has a slight risk for excessive rainfall over the area.

There will continue to be a chance of thunderstorms each day Friday through Sunday.

The Storm Prediction Center has a marginal risk for severe thunderstorms across southern areas on Friday. Damaging winds will be the main threat with any storms.

Also, The Weather Prediction Center has a marginal to slight risk for excessive rainfall for the area on Friday, Saturday and Sunday as well. Heavy downpours from additional showers and thunderstorms may lead to localized flooding concerns on these days.

Looking at the next five days, AccuWeather senior meteorologist Alex Sosnowski said,"At times, a plume of moisture will extend from the Atlantic Ocean to the Northeastern states. This setup is sometimes referred to as an atmospheric river."

It's not about continuous rain, he said, it's rainfall rates of up to 3 inches per hour. "Rainfall of this intensity is more than enough to overwhelm storm drains and lead to street flooding and rapid rises along small streams."

This big storm system sending showers and thunderstorms across the Midwest and Northeast is not likely to occur in exactly the same areas as last weekend, he said. But repeated episodes of rain will have an effect.

"At this time, it appears the greatest risk for flooding rainfall around New York City will be from late Saturday night to Sunday," he said.

Once again, the warm Atlantic waters will contribute to the dangerous flooding risks in the Northeast, he said. According to AccuWeather Senior Meteorologist Dave Dombek, ocean temperatures in the mid-Atlantic region are several degrees above average this summer and are currently more like levels sometimes seen in late August.

Here's the next 48 hours at a glance, based on Highland Falls:

Here's the five-day forecast based on Stony Point:

• Thursday - A 30 percent chance of showers and thunderstorms, mainly after 5pm. Mostly sunny, with a high near 91. South wind 6 to 10 mph.
• Tonight - A 50 percent chance of showers and thunderstorms, mainly after midnight. Some of the storms could produce heavy rain. Increasing clouds, with a low around 72. South wind around 6 mph becoming calm in the evening.
• Friday - Showers and thunderstorms, mainly after 11am. Some of the storms could produce small hail, gusty winds, and heavy rain. High near 84. Calm wind becoming south around 6 mph in the afternoon. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
• Friday Night - Showers and thunderstorms, mainly before 8pm. Some of the storms could produce gusty winds and heavy rain. Patchy fog after 2am. Low around 70. Light southeast wind. Chance of precipitation is 80%. New rainfall amounts between a quarter and half of an inch possible.
• Saturday - A 40 percent chance of showers and thunderstorms, mainly after 2pm. Patchy fog before 8am. Otherwise, partly sunny, with a high near 85. Calm wind becoming south around 6 mph in the afternoon.
• Saturday Night - A chance of showers and thunderstorms. Mostly cloudy, with a low around 73. Chance of precipitation is 50%.
• Sunday - Showers likely. Mostly cloudy, with a high near 83. Chance of precipitation is 70%.
• Sunday Night - A 40 percent chance of showers and thunderstorms before 2am. Mostly cloudy, with a low around 71.

Here's where the most rain was measured on Sunday:

SEE ALSO:

• Additional NY Resources Deployed To Help Hudson Valley Flood Victims
• Full Service Returns On Hudson Line: Metro-North Railroad
• Flood-Damaged Key Roads To Reopen In Hudson Valley