Alert archive / Pennsylvania / Flash Flood Warnings in 2026
Flash Flood Warning 156, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 13, 2026, 8:06 AM EDT for Mercer County, Middlesex County, New Jersey; 4 counties in Pennsylvania. It was in force for 4 hr. 18 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Sep 13, 2026, 8:06 AM EDT (12:06 UTC)
- Expired
- Sep 13, 2026, 12:00 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Mercer County, NJ, Middlesex County, NJ, Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 48 km from the middle of the area, began a volume at 12:10 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 13, 8:15 AM EDT | FLASH FLOOD | Millbourne, PA | Cobbs Creek in Philadelphia rapidly rose into flood stage. |
| Sep 13, 8:18 AM EDT | FLASH FLOOD | Darby Twp, PA | Delaware County EOC reported a couple of water rescues in Darby Township with related road closures. |
| Sep 13, 8:18 AM EDT | FLASH FLOOD | Lansdowne, PA | Delaware County EOC reported a water rescue in Lansdowne with a road closure. |
| Sep 13, 8:22 AM EDT | FLASH FLOOD | 1 W Chester Twp, PA | PennDOT reported flooding on I-95 southbound at US 322 West in West Chester. One lane is restricted. |
| Sep 13, 8:30 AM EDT | FLASH FLOOD | 1 Nw Mount Airy, PA | The Cresheim Creek in northwest Philadelphia quickly rose out of its banks and is flooding portions of Cresheim Drive that runs along it. |
| Sep 13, 8:49 AM EDT | FLASH FLOOD | 2 Ne Fairless Hills, PA | PennDOT reported flooding on Lincoln Highway/Woolston Drive westbound at US 1 South. A ramp is closed. |
| Sep 13, 9:00 AM EDT | FLASH FLOOD | 1 E Gardendale, PA | US 322 near the intersection with PA 452 has an inch of mud across the roadway due to construction and flash flooding runoff in Upper Chichester Township. |
| Sep 13, 9:00 AM EDT | RAIN 2.1 | Bustleton, PA | |
| Sep 13, 9:16 AM EDT | FLASH FLOOD | 1 Ssw Eastwick, PA | PennDOT reported flooding on I-95 northbound between Exit 12/PA 291 and Exit 13/I-76. There is a lane restriction. |
| Sep 13, 9:24 AM EDT | RAIN 2.5 | 2 S Fairless Hills, PA | |
| Sep 13, 9:32 AM EDT | FLASH FLOOD | Eddystone, PA | PennDOT reported flooding on I-95 southbound at the exit for Macdade Boulevard resulting in a ramp restriction. |
| Sep 13, 9:45 AM EDT | RAIN 2.15 | Mercerville, NJ | |
| Sep 13, 9:59 AM EDT | FLASH FLOOD | 1 Nnw Croydon, PA | PennDOT reported flooding on I-95 north of Exit 37/PA 132 West to US 13/Street Road/Bristol Pike. There is a lane restriction. |
| Sep 13, 11:00 AM EDT | RAIN 2.7 | Levittown, PA | |
| Sep 13, 12:00 PM EDT | RAIN 2.85 | 1 Nne Hamilton Square, NJ | Mesonet station FW9587 Hamilton. |
| Sep 13, 12:07 PM EDT | RAIN 2.17 | 1 S Robbinsville Twp., NJ | Mesonet station FW6272 Hamilton Township. |
| Sep 13, 12:07 PM EDT | RAIN 2.23 | 1 E Mercerville, NJ | Mesonet station CW7016 Mercerville. |
| Sep 13, 12:09 PM EDT | RAIN 2.13 | 1 E Lower Southampton T, PA | Mesonet station AV907 TREVOSE. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 0.1 hours before the alert went out and 195 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.
- Mixed-layer CAPE
- 677 J/kg
- Mixed-layer CIN
- -4 J/kg
- Mixed-layer LCL
- 475 m above ground
- 0-6 km bulk shear
- 37 kt
- 0-1 km storm-relative helicity
- 103 m²/s²
- 0-3 km storm-relative helicity
- 115 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 2.6
The text
As transmitted.
207
WGUS51 KPHI 131206
FFWPHI
NJC021-023-PAC017-045-091-101-131600-
/O.NEW.KPHI.FF.W.0156.260913T1206Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
806 AM EDT Sun Sep 13 2026
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Central Mercer County in central New Jersey...
Southwestern Middlesex County in northern New Jersey...
Southeastern Bucks County in southeastern Pennsylvania...
Delaware County in southeastern Pennsylvania...
Southeastern Montgomery County in southeastern Pennsylvania...
Philadelphia County in southeastern Pennsylvania...
* Until noon EDT.
* At 806 AM EDT, Doppler radar indicated heavy rain across the warned
area. Between 0.5 and 1.5 inches of rain have fallen across much of
the warned area. The expected rainfall rate is 0.5 to 1.5 inches in
1 hour. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by heavy rain.
SOURCE...Radar indicated.
IMPACT...Flash flooding of small creeks and streams, urban areas,
highways, streets and underpasses as well as other poor
drainage and low-lying areas.
* Some locations that will experience flash flooding include...
Philadelphia, Trenton, Bensalem, Ewing, Chester, Princeton, Yeadon,
Folcroft, Swarthmore, Hightstown and Jenkintown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
&&
LAT...LON 3986 7527 3981 7543 3985 7558 4011 7522
4026 7483 4037 7463 4040 7452 4027 7442
4017 7467 4018 7471 4015 7471 4013 7482
3999 7509
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...0.5-1.5 INCHES IN 1 HOUR
$$
Gorse3 follow-up statements
971
WGUS71 KPHI 131231
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
831 AM EDT Sun Sep 13 2026
NJC021-023-PAC017-045-091-101-131600-
/O.CON.KPHI.FF.W.0156.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-Bucks PA-Delaware PA-Montgomery PA-
Philadelphia PA-
831 AM EDT Sun Sep 13 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL NOON EDT TODAY FOR
CENTRAL MERCER, SOUTHWESTERN MIDDLESEX, SOUTHEASTERN BUCKS, DELAWARE,
SOUTHEASTERN MONTGOMERY AND PHILADELPHIA COUNTIES...
At 831 AM EDT, emergency management reported heavy rain in the warned
area. Flash flooding has been reported in portions of Delaware County
with related water rescues and road closures. In addition, small
creeks are running high with the Frankford Creek in Philadelphia
County rising rapidly. Between 0.5 and 2 inches of rain have fallen.
The expected rainfall rate is 0.75 to 1.75 inches in 1 hour. Flash
flooding is already occurring.
HAZARD...Life threatening flash flooding. Heavy rain producing flash
flooding.
SOURCE...Emergency management reported.
IMPACT...Life threatening flash flooding of creeks and streams, urban
areas, highways, streets and underpasses.
Some locations that will experience flash flooding include...
Philadelphia, Trenton, Bensalem, Ewing, Chester, Princeton, Yeadon,
Folcroft, Swarthmore, Hightstown and Jenkintown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 3986 7527 3981 7543 3985 7558 4011 7522
4026 7483 4037 7463 4040 7452 4027 7442
4017 7467 4018 7471 4015 7471 4013 7482
3999 7509
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...0.75-1.75 INCHES IN 1 HOUR
$$
Gorse568
WGUS71 KPHI 131337
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
937 AM EDT Sun Sep 13 2026
NJC021-023-PAC017-045-091-101-131600-
/O.CON.KPHI.FF.W.0156.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-Bucks PA-Delaware PA-Montgomery PA-
Philadelphia PA-
937 AM EDT Sun Sep 13 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL NOON EDT TODAY FOR
CENTRAL MERCER, SOUTHWESTERN MIDDLESEX, SOUTHEASTERN BUCKS, DELAWARE,
SOUTHEASTERN MONTGOMERY AND PHILADELPHIA COUNTIES...
At 937 AM EDT, emergency management and PennDOT reported flash
flooding. Several road closures have been reported in portions of
Delaware, Philadelphia and Bucks counties due to flooding. Small
creeks are running high in Delaware and Philadelphia counties,
however are receding. Between 1 and 2.5 inches of rain have fallen.
The heaviest rain continues to end from west to east across the
warned area. The expected rainfall rate is 0.25 to 1 inch in 1 hour.
Flash flooding is already occurring.
HAZARD...Life threatening flash flooding. Heavy rain producing flash
flooding.
SOURCE...Emergency management reported.
IMPACT...Life threatening flash flooding of creeks and streams, urban
areas, highways, streets and underpasses.
Some locations that will experience flash flooding include...
Philadelphia, Trenton, Bensalem, Ewing, Chester, Princeton, Yeadon,
Folcroft, Swarthmore, Hightstown and Jenkintown.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around, don't drown when encountering flooded roads. Most flood
deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 3986 7527 3981 7543 3985 7558 4011 7522
4026 7483 4037 7463 4040 7452 4027 7442
4017 7467 4018 7471 4015 7471 4013 7482
3999 7509
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...0.25-1 INCH IN 1 HOUR
$$
Gorse585
WGUS71 KPHI 131550
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
1150 AM EDT Sun Sep 13 2026
NJC021-023-PAC017-045-091-101-131600-
/O.EXP.KPHI.FF.W.0156.000000T0000Z-260913T1600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Middlesex NJ-Bucks PA-Delaware PA-Montgomery PA-
Philadelphia PA-
1150 AM EDT Sun Sep 13 2026
...FLASH FLOOD WARNING WILL EXPIRE AT NOON EDT TODAY FOR CENTRAL
MERCER, SOUTHWESTERN MIDDLESEX, SOUTHEASTERN BUCKS, DELAWARE,
SOUTHEASTERN MONTGOMERY AND PHILADELPHIA COUNTIES...
The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.
&&
LAT...LON 3986 7527 3981 7543 3985 7558 4011 7522
4026 7483 4037 7463 4040 7452 4027 7442
4017 7467 4018 7471 4015 7471 4013 7482
3999 7509
$$
GorseThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 13, 4:37 AM EDT | Special Marine Warning | PHI | 53 min | |
| Sep 13, 5:54 AM EDT | Flash Flood Warning | PHI | Morris | 6 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2026Flash Flood Warnings in New Jersey, 2026Every flash flood warning in 2026
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.