A complex area of low pressure over the middle Atlantic, which involved several individual centers, slowly consolidated off the Virginia Capes Tuesday morning, March 20th into Wednesday March 21st along a frontal boundary. This primary low, the fourth nor'easter of the month, gradually moved northeast Wednesday night to a position southeast of the 40 North/70 West Benchmark coordinates on Thursday morning.
Rain developed across southern and central Delaware on Tuesday morning, March 20th. As this precipitation moved northward into a colder air mass, snow and sleet developed across the remainder of northern Delaware during the Tuesday afternoon hours.
Northeast winds increased throughout Tuesday, and gusted 40 to 50 mph along the Atlantic and Delaware Bay Coasts from Tuesday afternoon into Wednesday morning.
Minor coastal flooding occurred along the Delaware oceanfront, as well as Delaware Bay, around the times of high tide Tuesday night, Wednesday morning, and again Wednesday night.
During Tuesday evening, a mixed bag of precipitation developed, with freezing rain, sleet, and snow, except rain closer to the coast.
Freezing rain lead to ice accretion up to 0.20 across portions of northern Delaware, causing downed trees and limbs, which impacted power lines, and lead to power outages.
The change over to snow progressed southeast across Delaware by late morning on Wednesday, March 21st, with the exception of Sussex County Delaware, where it did not occur until the early to mid-afternoon.
Moderate to heavy snowfall developed, and gradually overspread Delaware from Wednesday morning into the evening. Snowfall rates, particularly outside of southern Delaware, were around one inch per hour at times. The snow gradually ended from west to east around midnight.
Snowfall amounts generally ranged 6 to 9 inches in New Castle County, 3 to 6 inches in Kent County, and 1 to 3 inches in Sussex County.
The weight of the heavy, wet snow brought down trees, limbs, and power lines across portions of Delaware, which lead to power outages.