The remnants of Tropical Storm Lee that interacted with a stalled frontal boundary produced several days of periods of heavy rain across Delaware from the 5th into the 8th. Event precipitation totals averaged 2 to 5 inches, but exceeded 10 inches around Seaford in Sussex County. The greatest impact was mainly poor drainage flooding during periods of heavier rain.
Tropical Storm Lee made landfall in Louisiana during the morning of the 4th and moved slowly northeast. An approaching cold front from the Mississippi Valley reached Lee by the morning of the 5th and transformed it to an extratropical system on the 5th in Mississippi. The same cold front acted as a conduit for Lee's moisture farther to the northeast. Showers and thunderstorms from that approaching cold front arrived during the evening and overnight on the 5th. The front then stalled just south of Delmarva on the 6th. A relative lull in the rain then occurred during the morning of the 6th. As the front started to back north as a warm front later in the day on the 6th, more bands of heavier rain returned that afternoon and early evening. A blocking weather pattern then kept the frontal boundary in place from the morning of the 7th into the morning of the 8th just north of the state. Most of the precipitation on the 7th remained west of Delaware. A couple of bands of showers and thunderstorms with heavier rain then formed and moved across the state during the first half of the day on the 8th. Flash flooding producing thunderstorms formed over Sussex County during the afternoon of the 8th. The frontal boundary started to drift offshore and just a few leftover showers moved through on the morning of the 9th.

Flood in NEW CASTLE, DELAWARE
From 06-SEP-11 16:27:00 to 07-SEP-11 06:43:00 (EST-5)
Location: COOCHS BRIDGE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Christina River at Coochs Bridge had moderate flooding and was above its 10.5 foot flood stage from 527 p.m. EDT on the 6th through 743 a.m. EDT on the 7th. It crested at 11.8 feet at 945 p.m. EDT on the 6th. The Red Clay Creek at Stanton, just touched its 15 foot flood stage at Midnight EDT on the 7th. The entire event precipitation totals in New Castle County included 4.24 inches in Hockessin, 4.17 inches in Newark, 4.16 inches in Greenville, 3.48 inches in New Castle, 3.23 inches in Glasgow and 3.00 inches at the New Castle County Airport.

Flash Flood in SUSSEX, DELAWARE
From 08-SEP-11 15:30:00 to 08-SEP-11 18:30:00 (EST-5)
Location: BLADES
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorms with torrential downpours caused flash flooding of roadways and fields in and mainly to the west of Seaford in western Sussex County. Sections of Stein Highway (Delaware State Route 20) and Figgs Road were among about a dozen roads that were closed by flash flooding. Many roadways within Seaford itself had high water on them. Delaware State Route 20 and Ellis Mill Road suffered washouts. The Seaford School District was closed the following day, September 9th. Doppler Radar storm total estimates for the entire event in the flash flood area exceeded 10 inches. Other event precipitation totals in Sussex County included 4.60 inches in Milford and 2.76 inches in Georgetown.

Flood in NEW CASTLE, DELAWARE
From 08-SEP-11 08:15:00 to 08-SEP-11 10:41:00 (EST-5)
Location: WILMINGTON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Brandywine Creek at Wilmington was above its 16.5 foot flood stage from 915 a.m. EDT through 1141 a.m. EDT on the 8th.  It crested at 16.7 feet at 1015 a.m. EDT on the 8th.