Nor’easter to bring prolonged rain, strong northeast winds and tidal flooding to Eastern Shore

A developing coastal low and persistent northeast winds are expected to bring several days of wet, windy and potentially disruptive weather to Accomack and Northampton counties this week, with the most significant effects expected from Tuesday night through Thursday.

The National Weather Service in Wakefield says confidence is increasing that the coastal system will produce a prolonged period of rain, cooler temperatures and strong onshore winds across the region. A good old fashioned nor’easter, with strong high pressure building to the north while low pressure strengthens offshore of the Virginia and North Carolina coasts.

Rain chances will increase Monday as a slow-moving front approaches, but the more persistent unsettled weather is expected to develop Tuesday and continue through much of the week. The Weather Service says rain will be possible each day, and some computer guidance continues to show localized areas receiving significant rainfall. Flash flooding could occur where heavier rain repeatedly develops.

For the Eastern Shore, one of the biggest concerns will be the prolonged northeast wind. Winds are expected to begin increasing Tuesday, with gusty conditions along the coast continuing through at least Friday.

Those winds are expected to push water toward both the Chesapeake Bay and Atlantic sides of the Shore. The Weather Service says widespread minor to moderate tidal flooding is likely by the middle of the week, with water reaching one to two feet above ground level in vulnerable areas and localized flooding of two to three feet possible.

No tidal flooding is expected through Tuesday, but water levels are forecast to rise sharply Wednesday. Minor flooding could begin with Wednesday morning’s high tide, followed by minor to moderate flooding Wednesday evening. Localized major tidal flooding cannot be ruled out, and elevated water levels could continue through several tide cycles as northeast winds remain strong.

Conditions on the water could become particularly dangerous. Northeast winds are forecast to increase to 20 to 30 knots Tuesday, with confidence growing in frequent gale-force gusts Wednesday and Thursday. Offshore gusts of 35 to 40 knots are expected, and a period of 40- to 45-knot gusts is possible. Seas could build to 10 to 13 feet or higher.

The strongest marine conditions are expected Wednesday and Thursday, although gale-force gusts could begin north of Parramore Island as early as late Tuesday afternoon. Boaters and watermen should expect increasingly hazardous conditions as the week progresses.

The prolonged onshore flow will also affect the seaside beaches of Accomack and Northampton counties. Dangerous surf conditions are expected by midweek, and localized beach erosion will be possible as strong northeast winds and large waves continue.

Temperatures will also turn noticeably cooler. The Weather Service expects the combination of clouds, rain and northeast winds to hold temperatures down Tuesday and Wednesday, with coastal areas likely remaining considerably cooler than the warmer weather experienced over the weekend.

Forecasters caution that the exact track and strength of the coastal low remain uncertain. A secondary low could also develop offshore later in the week, which could extend the period of wind, rain and high water into Friday or beyond.

Residents in low-lying bayside and seaside communities should monitor later forecasts closely, particularly for coastal flood advisories or warnings and marine warnings as confidence increases in the timing and strength of the system.