Three weather features helped set the stage for some of the worst coastal flooding the region has seen since Hurricane Sandy in 2012. The first feature was Hurricane Joaquin. Joaquin evolved from a non-tropical low into a tropical depression on September 28, southwest of Bermuda. Joaquin then became a tropical storm on September 29, drifting slowly southwestward toward the Bahamas. Joaquin then underwent rapid intensification, reaching hurricane strength on September 30 and major hurricane (Cat 3) status on October 1. Against numerical guidance solutions, Joaquin continued to drift slowly to the southwest, before finally beginning to curve back to the north on October 2. On October 3, Joaquin began to increase forward speed, intensifying to Category 5 strength, acquiring sustained winds of 155 mph. This made Joaquin the strongest Atlantic hurricane since Hurricane Igor in 2010. The storms central pressure bottomed out at 931mb around 00z on October 2. Joaquin weakened, but remained a hurricane on October 4, passing well off the Mid-Atlantic Coast through October 6. While numerical and statistical guidance performed poorly with the track of Joaquin, this review will focus more on the impact of coastal flooding and not on Joaquin's track.

The second feature was a cold front that swept across the Mid-Atlantic region the evening of September 30. The front then stalled just off the Mid-Atlantic coast on October 1, and remained along to just offshore through October 6. Height falls from a deepening eastern CONUS trough produced an area of low pressure off the SC coast, which provided the focus for an extreme rainfall event across the Carolinas. It wasn't until Hurricane Joaquin lifted well offshore that the front finally began to push well offshore. The front provided a focus, when coupled with prolonged onshore flow, for a prolonged period of cloudy and wet weather. Norfolk and Elizabeth City recorded 6 and 7 days of rainfall, respectively. Numerical and statistical guidance also struggled with rainfall amounts across the region, with as much as 7 to 10 inches forecast early in the event. Precipitation totals ended up in the 1 to 3 inch range inland and 3 to 6 inches in southeast Virginia. The highest amounts were recorded in Isle of Wight County and the Peninsula, where amounts up to 10 inches were reported. Heavy rainfall exacerbated the coastal flooding during periods of high tide. Numerous days of cloudy and wet weather also resulted in significant crop damage.

http://www.weather.gov/akq/CoastalStormOct2015