Coastal Flood in Delaware, May 11 to 12, 1998

A persistent northeast flow caused by a high pressure system building south from Canada and a couple of low pressure systems that moved off the Middle and South Atlantic States produced minor coastal flooding from the 10th through the 13th. Tidal flooding became locally moderate during the evening high tides on the 11th and 12th, especially in the inlets. The water in the inlets had a hard time draining because of the persistent onshore winds. Tidal departures averaged about 1.5 to 2.0 feet above normal at times of high tide along the ocean front. Tides were already astronomically high because of the full moon. The highest tides occurred during the evening of the 11th. At Lewes, the tide was 6.7 feet above mean lower low water that evening. In addition to the tidal flooding, the pounding surf created more erosion problems along the shore. A low pressure system developed over Virginia on the 8th. It moved offshore by the morning of the 9th and was about 275 miles eastsoutheast of Indian River Inlet. Unfortunately, it was caught by a closed low at higher levels of the atmosphere and drifted slowly south through the 10th. Meanwhile a high pressure system was slowly building south into the United States from Canada. Another low pressure system moved into the Tennessee Valley the morning of the 10th and moved off the South Carolina Coast the morning of the 11th. These two lows combined into one east of Cape Hatteras, North Carolina by the morning of the 12th and remained nearly stationary through the 14th. The high pressure system eventually built far enough south to end the onshore flow across the area.