A southern low rapidly intensified as it raced up the East coast Sunday, and over NYC Sunday Night. This low brought a rapid onset but relatively brief period of SE gale to storm force winds Sunday evening, shifting to WNW gales Monday morning. High seas built into Monday Morning.
Moderate coastal flooding occurred along the Great South Bay with the Monday morning high tide. Surge continued to increase well after peak onshore winds, with water levels receding briefly or not at all during low tide. The westerly wind shift helped slosh surge into eastern portions of the Great South Bay, with recession below flood levels taking several hours after high tide.

Coastal Flood in SOUTHEAST SUFFOLK, NEW YORK
From 30-OCT-17 05:00:00 to 30-OCT-17 06:00:00 (EST-5)
Property damage: 3.00M
Crop damage: 0.00K
Reported by: Official NWS Observations

The USGS tidal gauge in Moriches at Moriches Bay recorded a peak water level of 5.4 ft. MLLW at 530 am EST, which is the moderate coastal flood threshold.
Numerous properties experienced 1 to 2 feet of inundation along Dune Rd. in Westhampton Beach. In Eastport, South Bay Avenue Marina was inundated by around 1 foot of water. In Mastic, widespread minor to moderate inundation of 1 to 3 feet occurred over roads and onto properties from Trafalgar and Pine Tree Drives and points to the southwest, and Trafalgar and Grandview Drives and points to the southeast. Smith Point Park in Mastic was also inundated.

Coastal Flood in SOUTHERN NASSAU, NEW YORK
From 30-OCT-17 03:00:00 to 30-OCT-17 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The USGS tidal gauge in Hudson Bay at Freeport recorded a peak water level of 6.6 ft. MLLW at 418 am EST. The moderate coastal flood threshold of 6.2 ft. MLLW was exceeded from 342 to 448 am EST. The moderate coastal flooding thresholds were established by the National Weather Service, based on impact analysis and collaboration with the USGS and local emergency management.

Coastal Flood in SOUTHWEST SUFFOLK, NEW YORK
From 30-OCT-17 04:00:00 to 30-OCT-17 10:00:00 (EST-5)
Property damage: 3.00M
Crop damage: 0.00K
Reported by: Official NWS Observations

The USGS tidal gauge in Great South Bay at Lindenhurst recorded a peak water level of 3.7 ft. MLLW at 454 am EST. The moderate coastal flood threshold of 3.6 ft. MLLW was exceeded from 424 to 536 am EST. The USGS tidal gauge in Great South Bay at Sayville recorded a peak water level of 3.9 ft. MLLW at 642 am EST. The moderate coastal flood threshold of 3.5 ft. MLLW was exceeded from 448 to 854 am EST. Moderate inundation of around 2 feet was reported along numerous waterfront roads and properties in Bayshore, West Babylon, Babylon, Lindenhurst, Blue Point, Patchogue, and Sayville. In Brookhaven, major inundation of 3 to 5 feet occurred at Squassux Landing Marina along Carmans River, sinking some boats. In Bellport, moderate inundation of 1 to 3 feet was observed at Bellport Marina, sinking a number of boats and flooding a few waterfront business.
The USGS tidal gauge in Watch Hill on Fire Island recorded a peak water level of 4.2 ft. MLLW at 718 am EST. This exceeded the major coastal flood threshold of 4.5 ft. MLLW. The moderate coastal flood threshold of 3.6 ft. MLLW was exceeded from 512 to 924 am EST. On Fire Island, extensive damage in excess of $3 million occurred at Davis Park Marina due to a combination of 2 to 3 feet of inundation, long shore currents, and 1 to 2 feet of wave action.
The coastal flooding thresholds were established by the National Weather Service, based on impact analysis and collaboration with the USGS and local emergency management.