Flood and Heavy Rain in Pennsylvania, May 26 to 27, 2001

Name: Flood and Heavy Rain in Pennsylvania, May 26 to 27, 2001
Start: 2001-05-26T05:00
End: 2001-05-27T06:00
Location: Pennsylvania

May 26 to 27, 2001 · NWS PHI · 8 events in 7 counties and zones

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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 8

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 slow moving cold front and a very humid air mass preceding it helped generate showers and thunderstorms with heavy rain across most of Eastern Pennsylvania during the daylight hours on the 26th. Doppler Radar storm total estimates ranged between 1 and 4 inches with the heaviest rain falling in Chester County. While the heavy rain produced some urban and poor drainage flooding, no serious flooding was reported. Some minor flooding occurred along the East Branch of the Brandywine Creek the morning of the 27th. Storm totals included 2.78 inches in Springfield Township (Delaware County), 2.76 inches in Doylestown (Bucks County), 2.62 inches in Glenmoore (Chester County), 2.25 inches in Springtown (Bucks County), 2.02 inches in West Chester (Chester County), 1.97 inches in Pottstown (Montgomery County) and Bath (Northampton County), 1.83 at the Philadelphia International Airport, 1.81 inches at the Lehigh Valley International Airport and 1.71 inches at the Northeast Philadelphia Airport. The East Branch of the Brandywine Creek at Downingtown reached its 7 foot flood stage from 603 a.m. EDT through 7 a.m. EDT on the 27th. It crested at 7.09 feet at 630 a.m. EDT.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at May 26, 2:10 AM EST, 2 hours 50 minutes earlier.

Area forecast discussion, May 26, 2:10 AM EST, 2 hours 50 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
310 AM EDT SAT MAY 26 2001

DISC: UPPER LVL LOW OVER THE GREAT LAKES REGION FORECAST TO STAY PUT
THROUGH MOST OF THE HOLIDAY WEEKEND WITH VORT MAX/S MOVING ACROSS
THE CWA WITH THE GENERAL FLOW. AS A RESULT...CLOUDY SKIES WILL BE
THE RULE FOR A LOT OF THE TIME. HOWEVER SUNSHINE IS POSSIBLE
ESPECIALLY ON SUN AND THE WEEKEND WON/T BE A TOTAL WASHOUT SINCE
PRECIPITATION WON/T BE FALLING ALL THE TIME. THUNDERSTORMS ARE
POSSIBLE TODAY AND SUN...BUT MOST PARAMETERS ARE NOT SHOWING
CONDITIONS TOO FAVORABLE FOR SEVERE WEATHER. HAVE GONE WITH LIKELY
POPS IN MOST LOCATIONS TODAY AND TONIGHT...WITH CHANCE POPS ON
SUN...MAINLY LATER IN THE DAY OR IN THE EVENING HOURS. FLOODING
CANNOT BE RULED OUT BUT WILL BE MORE ISOLATED THAN WIDESPREAD IF IT
DEVELOPS. SHOWERS AND THUNDERSTORMS STILL POSSIBLE ON MON BUT THERE
COULD ALSO BE A FEW PEAKS OF SUN THROUGH THE CLOUDS SO HAVE GONE
WITH LESS PESSIMISTIC WORDING BY USING VARIABLE CLOUDINESS RATHER
THAN MOSTLY CLOUDY IN THE FIRST DAY OF THE EXTENDED.

DID NOT STRAY TOO FAR FROM MOS TEMP GUIDANCE IN THIS PACKAGE.

NO MAJOR CHANGES TO THE EXTENDED FIN THIS PACKAGE.

NOTHING ON THE MARINE AT THE CURRENT TIME...AND NOT EXPECTING ANYTHING
IN THE NEAR FUTURE.

.PHI...NONE.

JJM

The radar

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

Open the radar archive at this moment

Event by event

7 heavy rain, 1 flood. Local standard time, as filed.

Heavy Rain, Bucks

When: May 26, 5:00 AM EST to 6:00 PM 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, Chester

When: May 26, 5:00 AM EST to 6:00 PM 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: May 26, 5:00 AM EST to 6:00 PM 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, Lehigh

When: May 26, 5:00 AM EST to 6:00 PM 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, Montgomery

When: May 26, 5:00 AM EST to 6:00 PM 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, Northampton

When: May 26, 5:00 AM EST to 6:00 PM 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)

Heavy Rain, Philadelphia

When: May 26, 5:00 AM EST to 6:00 PM 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)

Flood, Chester

When: May 27, 5:03 AM EST to 6:00 AM EST
Where: Chester forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

What these are

Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Pennsylvania in 2001 Every state in 2001 This day in weather history Warnings in Pennsylvania, May 2001

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: 5244822, 5244823, 5244824, 5244825, 5244826, 5244827, 5244828, 5244829.