The low pressure system that was Tropical Storm Hermine began to move back toward the west on Monday and the motion brought it closer to Long Island. At 8:00 p.m. EDT on Monday the center of Post Tropical Storm Hermine was located at latitude 39.3°N and longitude 70.3°W which put it about 135 miles south of Nantucket Island. Hermine was moving toward the west-northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 997 mb.
A Tropical Storm Warning remains in effect for the portion of the coast from Fire Island Inlet to Port Jefferson Harbor on Long Island and from New Haven, Connecticut to Sagamore Beach, Massachusetts including Block Island, Martha’s Vineyeard and Nantucket Island. Most of the stronger winds are occurring over water, but a weather station at Nantucket, Massachusetts reported a sustained wind speed of 44 m.p.h. (71 km/h) and a wind gust ot 56 m.p.h. (90 km/h) on Monday.
Post Tropical Storm Hermine has not had the structure of a tropical cyclone for several days. There are no thunderstorms near the center of circulation. The taller clouds are all occurring west of the center. The circulation pulled in drier air which has circulated into the core of the circulation. An upper level low south of Hermine has generated southeasterly winds which are blowing across the top of the circulation. The vertical wind shear combined with the drier air to prevent the development of new thunderstorms near the center of circulation.
The environment around Post Tropical Storm Hermine could become a little less hostile on Tuesday. It will be moving over water where the Sea Surface Temperature (SST) is near 25.5°C. As Hermine moves west the vertical wind shear will decrease. However, the cyclone is surrounded by dry air. If the surface low moves west, the complex environment could allow the system to maintain its intensity for another day or so. If the surface low moves farther north, it will move over cooler SSTs and the wind speeds will decrease.
The upper low to the south of Post Tropical Storm Hermine and a ridge north of Hermine are combining to steer it toward the west-northwest. That general motion is expected to continue for a few more hours. As Post Tropical Storm Hermine interacts with the upper low, it could make a slow cyclonic loop. On its expected track Hermine could move closer to Long Island on Tuesday.
Post Tropical Storm Hermine will continue to produce modest water rises along the coast. In addition persistent wind and wave action will generate more beach erosion.