Pennsylvania, 1999

Heavy Rain in Pennsylvania, August 13 to 14, 1999

August 13 to 14, 1999 · NWS PHI · 5 events in 5 counties and zones

00 inches in many places. Even heavier rain fell over parts of lower Bucks County where flash flooding of some streams occurred.

Where it happened

Every event with a place to put it; 5 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

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The toll

Deaths
0
Injuries
0
Property damage
None recorded
Crop damage
None recorded
Events
5

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.

In addition to the frequent lightning, the thunderstorms that rumbled through Southeast Pennsylvania brought heavy rain with them as storm totals ranged between 1.5 and 3.00 inches in many places. Even heavier rain fell over parts of lower Bucks County where flash flooding of some streams occurred. This was the most widespread rain event in the area since May 24th and started to chip away at the drought. Heavy rain fell mainly between 1100 p.m. EDT on the 13th and 3 a.m. EDT on the 14th. Multiple thunderstorms enhanced the storm totals across Lower Montgomery and Bucks Counties and the northern half of Philadelphia. The rain caused the usual urban and poor drainage flooding problems. Storm totals included 2.98 inches at the Northeast Philadelphia Airport, 2.77 inches at the Willow Grove NAS, 2.62 inches in Valley Forge (Montgomery/Chester County Line), 2.60 inches in Pottstown (Montgomery County), 2.49 inches in Palm , 2.31 inches in Perkasie (Bucks County), 1.67 inches at the Franklin Institute within Philadelphia and 1.45 inches in Glenmoore (Chester County).

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

5 heavy rain. Local standard time, as filed.

Heavy Rain, Bucks

When
August 13, 10:00 PM EST to August 14, 2:00 AM EST
Where
Bucks County, Springtown
Reported by
AWOS,ASOS,MESONET,ETC
Coordinates
40.337, -75.107 (the zone’s center; the record gives no point)

Heavy Rain, Chester

When
August 13, 10:45 PM EST to August 14, 1:00 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, Montgomery

When
August 13, 10:45 PM EST to August 14, 1:30 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 13, 11:45 PM EST to August 14, 2:00 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, Delaware

When
August 14, 12:20 AM EST to 2:00 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)

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

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: 5717865, 5717965, 5717967, 5717968, 5717966.