Flood in Pennsylvania, June 20 to 21, 2003

Name: Flood in Pennsylvania, June 20 to 21, 2003
Start: 2003-06-20T16:25
End: 2003-06-21T21:03
Location: Pennsylvania

June 20 to 21, 2003 · NWS PHI · 1 event in 1 county or zone

A slow moving low pressure system at both the surface and aloft helped trigger very heavy rain across Delaware County from the late morning into the afternoon 20th. 0 inches, most of which fell during the afternoon at the rate of half an inch per hour.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

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 low pressure system at both the surface and aloft helped trigger very heavy rain across Delaware County from the late morning into the afternoon 20th. Storm totals averaged between 2.0 and 4.0 inches, most of which fell during the afternoon at the rate of half an inch per hour. The heavy rain led to widespread poor drainage flooding as well as flooding of most of the gaged rivers and streams in the county. The worst flooding occurred along the Chester Creek. About 60 homes were evacuated along Powell Road in Chester City and suffered basement flooding. In Birmingham Township in the Chadds Ford area, a couple of roads were closed along Harvey Run. The Chester Creek in Chester was above its 8 foot flood stage from 534 p.m. EDT on the 20th through 510 a.m. EDT on the 21st. It crested at 14.63 feet at 830 p.m. EDT on the 20th. The Crum Creek at Newtown Square was above its 6 foot flood stage from 525 p.m. EDT on the 20th through 1204 a.m. EDT on the 21st. It crested at 8.72 feet at 8 p.m. EDT on the 20th. Along the county border with Chester County, the Brandywine Creek at Chadds Ford was above its 9 foot flood stage from 555 p.m. EDT on the 20th through 1003 p.m. EDT on the 21st. It crested at 12.82 feet at 457 a.m. EDT on the 21st. The water saturated soil, mudslides and the general flooding caused trees to fall. About 29,000 PECO Energy customers lost power. No serious injuries were reported. Storm totals included 4.03 inches in Havertown, 3.70 inches in Aston and 2.25 inches in Springfield Township. The low pressure system responsible for the heavy rain formed along a stationary front over the Carolinas during the morning of the 20th. It moved to just east of Wallops Island, Virginia during the evening of the 20th and well east of the Delmarva Peninsula during the morning of the 21st. An inverted trough at the surface that extended from the low north into Chesapeake Bay and Eastern Pennsylvania concentrated the heavy rain along its axis. June as a whole was an unseasonably wet month. On a county weighted average, June monthly precipitation totals averaged 8.0 inches in Delaware County. Normal is around 3.4 inches. The June monthly precipitation total of 8.08 inches at the Philadelphia International Airport was the second wettest on record. The wet spring weather led to a whole different set of problems from the drought of the previous year. Planted seeds were drowning and rotting. Many soybean, corn and berry fields were too wet. There were also problems with slugs. Vegetables were generally about a month behind. Double crop fields fell behind schedule because of the slow growth of straw and hay. Garden shops sales have been down. Pool installations were about three to six weeks behind. Ant infestations increased. Windshield wipers were tearing. Many spring athletic seasons were extended because of postponed events. There will be a bumper crop of mosquitoes. Attendance along the shore and at amusement parks was down. Road work was delayed. The one few positives from the wet weather was lower utility bills.

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 Jun 20, 2:45 PM EST, 1 hour 40 minutes earlier.

Area forecast discussion, Jun 20, 2:45 PM EST, 1 hour 40 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
345 PM EDT FRI JUN 20 2003

DISC: BY LOCAL EXCSSV RAINFALL CHECKLIST STANDARDS...WE CAME UP SHRT
FOR WATCH CRITERIA...HOWEVER...GIVEN THE STATE OF THE GROUND(SINCE
OCT) AND THE PROLONGED EVENT WE ARE IN SOME AREAS WILL EXPERIENCE
FLOODING ESP WHERE CONVECTION OCCURS OVER OUR FLASHY BASINS. THE 12Z
RUNS HAVE COME TOGETHER AS FAR AS THE 3-4 INCH BULLSEYE BUT THE ETA
GIVES US LESS THIS RUN THAN EARLIER AND HAS SHIFTED THE MAX AMNTS
FROM SNJ TO LEHIGH VALLEY PER GFS. BEING A PROLONGED EVENT IS
FAVORABLE FOR REDUCING FLOODING ON LARGER RIVERS/STREAMS BUT SOME
ISOLATED CONV LIKELY TO SEND SMALLER ONES TO OR OVER FS. THANKS TO
MARFC FOR DETAILED COOR THIS MRNG. WITH THE HIGHER QPF ANTICIPATED
TO BE ACROSS THE LEHIGH VALLEY AND INTO NW NJ...THE FLD WATCH HAS
BEEN SHAVED BACK ACROSS THE SOUTH. THE HIGHER TERRAIN IN NE PA AND
NW NJ WILL BE MORE FAVORABLE FOR HEAVIER RAIN DUE TO TERRAIN
ENHANCEMENT ALONG W/ A POSSIBLE DEFORMATION ZONE. THIS ALSO LINES
UP WELL WITH MORE UPWARD MOTION IN THE MODELS.

PCPN CURRETNLY OVER THE REGION IN RESPONSE TO S/W RACING THRU WRN PA
ATTM. 700MB LOW OVER PIT HANDELD BEST BY ETA TRACKS TO THE SE WITH
MAX PCPN PIVOTING NE THRU NRN NJ/ERN PA IN TIME WHILE CONSIDERABLY
LESS PCPN OVER SRN AREAS. SOME LIGHTER PCPN DEVELOPING ON BACK SIDE
OF LWR IN ERN OHIO.

PLEASE CHECK LATEST FFWS ISSUED THIS AFTERNOON FOR SOME SE PA/NRN DE
STREAMS ALREADY REACHING FS.

TIDAL DEPARTURES CONSISTENLY 1-1.5 FT ABV NRM NEXT 48 HRS BUT AT A
LOW ATSTRONOMICAL PERIOD ALTHO THE BACK BAYS MAY LOOK A LITTLE HIGH
TO SOME.

DRYING WILL TAKE PLACE FROM LATE SUN ON AS UPPER RIDGE BUILDS ACROSS
THE MID ATLANTIC BUT SHORT LIVED AS COUPLE OF FAST MOVING FRONTS
PASS THROUGH THE AREA WITH SHOWER TYPICAL SUMMERTIME PCPN
POSSIBLE. TEMPS ALSO LIKELY TO REACH INTO THE MID/UPPER 80S WITH A
SHOT AT 90.

WOODY - YOUR $S IN THE MAIL

FCSTID =   16
MPO   59  66  58  76 /  90  90  70  30
ABE   62  68  60  78 /  90  80  70  30
RDG   62  68  60  78 /  90  80  70  30
PHL   64  70  62  78 /  80  70  70  30
12N   59  66  58  76 /  90  90  70  30
SMQ   61  69  60  77 /  90  90  70  30
TTN   61  69  60  77 /  90  90  70  30
MIV   61  68  60  77 /  80  70  70  30
ACY   62  65  61  74 /  80  70  70  30
ILG   62  70  61  78 /  80  70  70  30
DOV   61  69  61  78 /  80  70  70  30
GED   61  69  61  78 /  80  70  70  30
ESN   61  69  61  78 /  80  70  70  30

.PHI...
DE...FLOOD WATCH FOR TONIGHT THROUGH SATURDAY NIGHT FOR ZONE DEZ001.

MD...FLOOD WATCH FOR TONIGHT THROUGH SATURDAY NIGHT FOR ZONE MDZ008.

NJ...FLOOD WATCH FOR TONIGHT THROUGH SATURDAY NIGHT FOR ZONES
NJZ001...NJZ007>010...NJZ012>019.

PA...FLOOD WATCH FOR TONIGHT THROUGH SATURDAY NIGHT FOR ZONES
PAZ054>055...PAZ060>062...PAZ067>071.

EBERWINE/GORSE

Hazardous weather outlook, Jun 20, 4:50 AM EST, 11 hours 35 minutes before

DEZ001>004-MDZ008-012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-067>071-201200-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
550 AM EDT FRI JUN 20 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL AND SOUTHEAST
PENNSYLVANIA...DELAWARE...THE NORTHERN MARYLAND EASTERN SHORE...AND
NEW JERSEY EXCLUDING THE FIVE NORTHEAST COUNTIES.

.DAY ONE...TODAY

A FLOOD WATCH IS IN EFFECT FOR THE ENTIRE AREA TODAY AND TONIGHT.
RAIN...HEAVY AT TIMES...COULD PRODUCE FLOODING ESPECIALLY ALONG
SMALL STREAMS AND CREEKS...IN URBAN AREAS..AND IN POOR DRAINAGE
LOCATIONS. SEE FLOOD WATCH STATEMENT UNDER WMO HEADER /WGUS61 KPHI/
FOR MORE DETAILS.

THERE IS A LOW TO OCCASIONALLY MODERATE RISK FOR RIP CURRENTS TODAY
DURING RISING TIDE ALONG THE NEW JERSEY AND DELAWARE COASTS.

.DAYS TWO THROUGH SEVEN...

THE FLOOD WATCH WILL CONTINUE SATURDAY. RAIN HEAVY AT TIMES WILL
CONTINUE SATURDAY...AND POSSIBLY INTO SATURDAY NIGHT...AND COULD
PRODUCE ADDITIONAL FLOODING PROBLEMS ESPECIALLY ALONG SMALL STREAMS
AND IN URBAN AREAS WITH POOR DRAINAGE. SCATTERED SHOWERS MAY LINGER
SUNDAY AS WELL.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

The radar

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

Open the radar archive at this moment

Event by event

1 flood. Local standard time, as filed.

Flood, Delaware

When: June 20, 4:25 PM EST to June 21, 9:03 PM EST
Where: Delaware forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 39.917, -75.399 (the zone’s center; the record gives no point)

What these are

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 2003 Every state in 2003 This day in weather history Warnings in Pennsylvania, June 2003

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: 5376228.