A series of low pressure systems that brought between two and four inches of rain from the evening of the 28th into the early morning of the 31st. Coupled with already wet antecedent conditions, this caused renewed flooding in southeastern Pennsylvania. The heaviest rain came in two shots, one that fell from the evening of the 28th into the early morning of the 29th and the second that fell during the daylight hours on the 30th.
The heavy rain was caused by a series of low pressure systems. The first one emerged from the southern Rockies on the morning of the 27th, reached the lower Ohio Valley on the morning of the 28th and started to weaken. Another low pressure system formed on its occluded front farther to the south and by 2 a.m. EDT on the 29th reached the Washington D.C. Metropolitan Area. This low pressure system too weakened as yet another one formed along the Carolina Coast during the morning of the 29th. This low pressure system moved slowly north and at 8 p.m. EDT on the 29th was located off of the North Carolina coast. It continued to intensify and at 8 a.m. EDT on the 30th, it was a 992 millibar low pressure system east of Atlantic City, New Jersey and at 2 p.m. EDT on the 30th, a 988 millibar low pressure system just south of Long Island, New York. From there it was captured by the upper level low and slowly weakened. At 8 p.m. EDT on the 30th, the surface low pressure system was located over central Long Island and then drifted very slowly southeast overnight.
This culminated a much wetter than normal month of March for Southeastern Pennsylvania. At the Philadelphia International Airport, the monthly precipitation total of 7.33 inches was the third wettest March on record.

Flood in MONTGOMERY, PENNSYLVANIA
From 30-MAR-10 14:39:00 to 30-MAR-10 20:10:00 (EST-5)
Location: SCHWENKSVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The East Branch of the Perkiomen Creek at Schwenksville was above its 7 foot flood stage from 356 p.m. EDT through 910 p.m. EDT on the 30th. It crested at 8.77 feet at 630 p.m. EDT. The Wissahickon Creek at Fort Washington was above its 9 foot flood stage from 339 p.m. EDT through 628 p.m. EDT on the 30th. It crested at 9.35 feet at 445 p.m. EDT. Event precipitation totals included 3.30 inches in Rockledge, 3.13 inches in Ardmore, 3.05 inches in Wynnewood and 2.81 inches in Willow Grove.

Flood in PHILADELPHIA, PENNSYLVANIA
From 30-MAR-10 15:13:00 to 30-MAR-10 18:17:00 (EST-5)
Location: TORRESDALE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Pennypack Creek at the Rhawn Street Bridge was above its 7 foot flood stage again from 413 p.m. EDT through 717 p.m. EDT on the 30th. It crested at 7.11 feet at 545 p.m. EDT.  Event precipitation totals included 3.03 inches at the Northeast Philadelphia Airport and 2.30 inches at the Philadelphia International Airport.

Flood in BUCKS, PENNSYLVANIA
From 30-MAR-10 19:45:00 to 31-MAR-10 00:00:00 (EST-5)
Location: LANGHORNE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Neshaminy Creek at Langhorne was above its 9 foot flood stage from 845 p.m. EDT on the 30th through 1 a.m. EDT on the 31st. It crested at 9.28 feet at 11 p.m. EDT on the 30th. Event precipitation totals included 3.60 inches in Langhorne, 3.55 inches in Penndel and 3.47 inches in Bensalem.

Flood in DELAWARE, PENNSYLVANIA
From 29-MAR-10 02:05:00 to 29-MAR-10 04:29:00 (EST-5)
Location: EDDYSTONE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Chester Creek at Chester was above its 8 foot flood stage from 341 a.m. EDT through 502 a.m. EDT on the 29th. It crested at 8.22 feet at 415 a.m. EDT.  The Crum Creek at Newtown Square was above its 6 foot flood stage from 305 a.m. EDT through 529 a.m. EDT on the 29th. It crested at 6.59 feet at 400 a.m. EDT. Event precipitation totals included 2.86 inches in Drexel Hill.

Flood in PHILADELPHIA, PENNSYLVANIA
From 29-MAR-10 03:10:00 to 29-MAR-10 07:42:00 (EST-5)
Location: TORRESDALE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: River/Stream Gage

The Pennypack Creek at the Rhawn Street Bridge was above its 7 foot flood stage from 410 a.m. EDT through 842 a.m. EDT on the 29th. It crested at 7.62 feet at 7 a.m. EDT. Event precipitation totals included 3.03 inches at the Northeast Philadelphia Airport and 2.30 inches at the Philadelphia International Airport.