Virginia

Virginia's tidal coast runs from the Maryland line at Chincoteague down the long stretch of the Eastern Shore, around the mouth of Chesapeake Bay at Cape Charles and Cape Henry, and on to the North Carolina border south of Virginia Beach. The Chesapeake Bay Bridge Tunnel gauge sits at the mouth of the Bay where the open Atlantic meets the brackish estuary that drains the entire Mid-Atlantic. Mean range at the gauge is about 0.9 metres, semidiurnal, with two highs and two lows of comparable size each day, twelve and a half hours apart. Spring tides push close to 1.1 metres and neaps drop near 0.7. Inside the Bay the range compresses further as the basin widens. The barrier-island system off the Eastern Shore — Wallops, Assateague, Smith — runs an open-Atlantic signal closer to the gauge readings. Surfers at Sandbridge and First Landing read the table for low-tide bar reshaping; flounder fishers at Lynnhaven Inlet time their drifts to the change. Nor'easter surge in autumn and winter and tropical-storm surge in late summer can both stack water levels well above predicted; the harmonic predictions on this site assume normal weather. NOAA CO-OPS runs the authoritative gauge network from Chincoteague to the CBBT.