Flood in Pennsylvania, December 11 to 12, 2003

Name: Flood in Pennsylvania, December 11 to 12, 2003
Start: 2003-12-11T05:27
End: 2003-12-12T02:18
Location: Pennsylvania

December 11 to 12, 2003 · NWS PHI · 1 event in 1 county or zone

m. m.

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.

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: 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.

The combination of heavy rain between 3 a.m. and 10 a.m. EST on the 11th and runoff from the melting snow produced widespread poor drainage and some stream and river flooding in Delaware County. Storm totals averaged around two inches with the highest amounts toward Chester County. The Unionville-Chadds Ford School District closed the school for the day.The Crum Creek at Newtown Square was above its 6 foot flood stage from 527 a.m. EST through 953 a.m. EST on the 11th. It crested at 8.71 feet at 930 a.m. EST. The Brandywine Creek at Chadds Ford was above its 9 foot flood stage from 912 a.m. EST on the 11th through 218 a.m. EST on the 12th. It crested at 10.42 feet at 627 p.m. EST on the 11th.Storm totals included 2.61 inches in Chadds Ford and 1.51 inches at the Philadelphia International Airport. The primary low pressure system moved toward the Great Lakes on the morning of the 10th while a secondary low pressure system was forming near the upper air support over the Tennessee Valley. This secondary low pressure system continued to intensify and was located over North Carolina the evening of the 10th, near Philadelphia around 7 a.m. EST on the 11th and in western Connecticut early in the evening on the 11th. This secondary low pressure system helped wring the moisture in the atmosphere from the Gulf of Mexico and the Atlantic Ocean onto the region.

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 Dec 11, 4:15 AM EST, 1 hour 12 minutes earlier.

Area forecast discussion, Dec 11, 4:15 AM EST, 1 hour 12 minutes before

AREA FORECAST DISCUSSION - UPDATE
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
415 AM EST THU DEC 11 2003

NEGATIVELY TILTED SYS CONTINUES TO SHARPEN UP. AT 09Z RAPIDLY
DEEPENING LOW PRES LOCATED BTWN BWI AND IAD. NW TO SE ORIENTED
COLD FNT CONT MVG TWD NW AND IS APPROACHING THE CHESAPEAKE BAY.
CONCENTRATED AREA OF RA/+RA IN ADVANCE OF FNT ACCOMPANIED BY GUSTY
WINDS ESP NEAR COASTAL REGIONS...WITH LWR MD ESHORE REGION HITTING
38 MPH. FNT TO MOVE THRU FA +/- 12Z. RAIN COMBINED WITH SNOW MELT
HAVE ALREADY NECESSITATED FFW BEING ISSUED N DE...XTRM NE MD AND SE
PA. MORE WARNINGS PSBL AS HEAVIEST RAIN OF THIS EVENT MOVES INTO FA
FM THE S. WILL KEEP FFA IN EFFECT THRU THE MRNG.

WILL DROP DENSE FOG ADV. DENSE FOG PRIMARILY IN ELEVATED...IE IN
CLOUDS...REGIONS. NOT MUCH OR NO SNOW LEFT IN FA TO ADD MOISTURE
WHEN WINDS LIGHTEN UP A BIT TWRD FROPA. MARINE FCSTR WILL KEEP GALE
WRNG HOISTED FOR OCEAN AND BAY.

.PHI WATCHES/WARNINGS/ADVISORIES...
PA...FLOOD WATCH THIS MRNG ZONES 54/55/60>62/67>71.
NJ...FLOOD WATCH THIS MRNG ZONES 1/7>10/12/13/15>19.
DE...FLOOD WATCH THIS MRNG ZONE 1.
MD...FLOOD WATCH THIS MRNG ZONE 8.
MARINE/OCEAN...GALES SANDY HOOK NJ TO FENWICK IS DE. MARINE/DEL
BAY...GALES.

WOODWORTH

Hazardous weather outlook, Dec 11, 5:21 AM EST, 6 minutes before

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
521 AM EST THU DEC 11 2003

DEZ001>004-MDZ008-012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-067>071-111019-
ATLANTIC NJ-ATLANTIC COASTAL CAPE MAY NJ-BERKS PA-BUCKS PA-CAMDEN NJ-
CAPE MAY NJ-CARBON PA-CAROLINE MD-CECIL MD-CHESTER PA-
COASTAL ATLANTIC NJ-COASTAL OCEAN NJ-CUMBERLAND NJ-DELAWARE PA-
DELAWARE BEACHES DE-EASTERN MONMOUTH NJ-GLOUCESTER NJ-HUNTERDON NJ-
INLAND SUSSEX DE-KENT MD-KENT DE-LEHIGH PA-MERCER NJ-MIDDLESEX NJ-
MONROE PA-MONTGOMERY PA-MORRIS NJ-NEW CASTLE DE-NORTHAMPTON PA-
NORTHWESTERN BURLINGTON NJ-OCEAN NJ-PHILADELPHIA PA-QUEEN ANNES MD-
SALEM NJ-SOMERSET NJ-SOUTHEASTERN BURLINGTON NJ-SUSSEX NJ-TALBOT MD-
WARREN NJ-WESTERN MONMOUTH NJ-
521 AM EST THU DEC 11 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 THIS MORNING FOR PARTS OF THE
REGION...MAINLY AROUND THE GREATER PHILADELPHIA METROPOLITAN AREA
AND THE RARITAN BASIN. PLEASE REFER TO WGUS61 FLOOD WATCH STATEMENT
FOR FURTHER DETAILS. A GALE WARNING IS IN EFFECT ALONG THE COAST AND
THE DELAWARE BAY.

.DAYS TWO THROUGH SEVEN...

FOR THURSDAY THROUGH NEXT TUESDAY...THERE IS A CHANCE FOR A WINTRY
MIX OF PRECIPITATION ON SUNDAY AND MONDAY.

.SPOTTER CALL TO ACTION STATEMENT...

SPOTTER ACTIVATION NOT REQUESTED. STORM TOTAL AND ANY FLOODING
REPORTS GREATLY APPRECIATED.

CORRECTED TO ADD DELAWARE BAY TO GALE WARNING AREA.

WOODWORTH

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: December 11, 5:27 AM EST to December 12, 2:18 AM 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, December 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: 5328566.