Heavy Rain, Bucks
- When
- August 25, 10:00 PM EST to August 26, 4:00 AM EST
- Where
- Bucks County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 40.337, -75.107 (the zone’s center; the record gives no point)
Heavy Rain in Pennsylvania, August 25 to 26, 1999
A warm front that slowly tried to move through Eastern Pennsylvania during the early morning of the 26th helped trigger thunderstorms with heavy rain. A weak low pressure system that moved east from the Ohio Valley prevented the front from making much headway into the state.
Where it happened
Every event with a place to put it; 7 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 7
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
What happened
The episode as NWS PHI wrote it up.
A warm front that slowly tried to move through Eastern Pennsylvania during the early morning of the 26th helped trigger thunderstorms with heavy rain. A weak low pressure system that moved east from the Ohio Valley prevented the front from making much headway into the state. Heavy rain began along the Mason/Dixon line around 11 p.m. EDT on the 25th and spread into the Lehigh Valley around 1 a.m. EDT on the 26th. The heavy rain ended by daybreak on the 26th. Radar estimates, SKYWARN and Hydrological spotter reports showed that storm totals ranged from 1.0 to 2.5 inches across much of the area. The heaviest rain fell right along the Delaware River and in a band across extreme northern Chester, Montgomery and Bucks Counties into adjacent parts of the Lehigh Valley counties. The lightest rain fell across northwestern parts of the Lehigh Valley. Some poor drainage flooding occurred. Flooding was also reported from Lake Caroline Dam (Levittown) in Bucks County. No serious problems though were reported. Storm totals included 2.51 inches in Coopersburg (Lehigh County), 2.42 inches in Palm (Montgomery County), 2.40 inches at the Northeast Philadelphia Airport, 2.36 inches in Springtown (Bucks County), 2.34 inches in South Pottstown (Montgomery County), 2.05 inches in Bethlehem (Northampton County), 1.91 inches in Neshaminy Falls (Bucks County), 1.62 inches in West Chester (Chester County), 1.56 inches in Phoenixville (Chester County), 1.55 inches in Chadds Ford (Delaware County), 1.52 inches in Doylestown (Bucks County), 1.43 inches in Glenmoore (Chester County), 1.32 inches at the Philadelphia International Airport and 1.00 inch at the Lehigh Valley International Airport.
The radar
The national radar mosaic for the moment the first event began.
Event by event
7 heavy rain. Local standard time, as filed.
Heavy Rain, Chester
- When
- August 25, 10:00 PM EST to August 26, 4:00 AM EST
- Where
- Chester County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 39.973, -75.748 (the zone’s center; the record gives no point)
Heavy Rain, Delaware
- When
- August 25, 10:00 PM EST to August 26, 4:00 AM EST
- Where
- Delaware County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 39.917, -75.399 (the zone’s center; the record gives no point)
Heavy Rain, Montgomery
- When
- August 25, 10:00 PM EST to August 26, 4:00 AM EST
- Where
- Montgomery County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 40.211, -75.367 (the zone’s center; the record gives no point)
Heavy Rain, Philadelphia
- When
- August 25, 10:00 PM EST to August 26, 4:00 AM EST
- Where
- Philadelphia County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 40.008, -75.134 (the zone’s center; the record gives no point)
Heavy Rain, Lehigh
- When
- August 26, 12:00 AM EST to 4:00 AM EST
- Where
- Lehigh County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 40.613, -75.592 (the zone’s center; the record gives no point)
Heavy Rain, Northampton
- When
- August 26, 12:00 AM EST to 4:00 AM EST
- Where
- Northampton County, Countywide
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 40.754, -75.307 (the zone’s center; the record gives no point)
What these are
- Heavy Rain
- Rainfall totals unusual for the place and season that did not produce a flood.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Lightning Strike in Mississippi, August 25, 1999
- Flash Flooding and Heavy Rain in Maryland, August 25, 1999
- Damaging Wind and Lightning Strike in Virginia, August 25, 1999
- Hail and Damaging Winds in Mississippi, August 25, 1999
- Lightning Strike in Florida, August 25, 1999
- Flash Flooding and Hail in North Carolina, August 25, 1999
- Hail in Georgia, August 25, 1999
- Heavy Rain in Maryland, August 25, 1999
- Heavy Rain in New Jersey, August 25 to 26, 1999
- Drought in North Carolina, August 25, 1999
- Heavy Rain in Virginia, August 25, 1999
- Wildfire in Oregon, August 25, 1999
More
Every storm in Pennsylvania in 1999Every state in 1999This day in weather historyWarnings in Pennsylvania, August 1999
Sources
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5718082, 5718083, 5718084, 5718086, 5718088, 5718085, 5718087.