Alert archive / Pennsylvania / Flash Flood Warnings in 2026
Flash Flood Warning 103, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 5, 2026, 9:04 PM EDT for 4 counties in Pennsylvania. It was in force for 4 hr. 5 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
- Aug 5, 2026, 9:04 PM EDT (01:04 UTC)
- Expired
- Aug 6, 2026, 1:15 AM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 83 km from the middle of the area, began a volume at 01:07 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 |
|---|---|---|---|
| Aug 5, 9:05 PM EDT | FLASH FLOOD | 1 Wsw Phoenixville, PA | Several roads reported flooded in Phoenixville, including Nutt Road, Bridge Street and Schuylkill Road. |
| Aug 5, 9:20 PM EDT | FLASH FLOOD | 2 Nw Valley Forge, PA | Pawlings Road has water over it in several places. Flooding also on Ferry Lane. |
| Aug 5, 9:50 PM EDT | FLASH FLOOD | West Conshohocken, PA | Report from mPING: Street/road flooding; Street/road closed; Vehicles stranded. |
| Aug 5, 11:00 PM EDT | FLASH FLOOD | 1 Sse Fort Washington, PA | Severe flooding on PA Turnpike in Upper Dublin Township. Vehicles stranded water rescues on going. |
| Aug 5, 11:00 PM EDT | FLASH FLOOD | 1 Ssw Fort Washington, PA | Flooding on PA Turnpike in Whitemarsh Township. Vehicles stranded. |
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 00:00Z, 1.1 hours before the alert went out and 223 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
- 94 J/kg
- Mixed-layer CIN
- -35 J/kg
- Mixed-layer LCL
- 462 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 83 m²/s²
- 0-3 km storm-relative helicity
- 123 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
552
WGUS51 KPHI 060104
FFWPHI
PAC017-029-045-091-060515-
/O.NEW.KPHI.FF.W.0103.260806T0104Z-260806T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
904 PM EDT Wed Aug 5 2026
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Central Bucks County in southeastern Pennsylvania...
Northeastern Chester County in southeastern Pennsylvania...
North Central Delaware County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
* Until 115 AM EDT.
* At 904 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between
0.5 and 1 inch of rain has fallen across parts of the warned area.
The expected rainfall rate is 1 to 2.5 inches in 1 hour. Flash
flooding is ongoing or expected to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar and automated gauges.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
* Some locations that may experience flash flooding include...
Philadelphia, Norristown, Phoenixville, Lansdale, West Norriton,
East Norriton, Perkasie, Doylestown, Conshohocken, Hatboro,
Souderton and Ambler.
This includes the following highways...
Interstate 476 in Pennsylvania between mile markers 12 and 19.
Interstate 76 in Pennsylvania between mile markers 327 and 334.
Northeast Extension between mile markers 21 and 36.
Pennsylvania Turnpike between mile markers 317 and 344.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4035 7537 4041 7530 4023 7498 4009 7522
4009 7523 4008 7524 4004 7530 3995 7553
4013 7561 4019 7555
FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-2.5 INCHES IN 1 HOUR
$$
Gorse3 follow-up statements
170
WGUS71 KPHI 060130
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
930 PM EDT Wed Aug 5 2026
PAC017-029-045-091-060515-
/O.CON.KPHI.FF.W.0103.000000T0000Z-260806T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Chester PA-Delaware PA-Montgomery PA-
930 PM EDT Wed Aug 5 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 115 AM EDT THURSDAY
FOR CENTRAL BUCKS, NORTHEASTERN CHESTER, NORTH CENTRAL DELAWARE AND
CENTRAL MONTGOMERY COUNTIES...
At 930 PM EDT, the public reported thunderstorms producing heavy
rain across portions of the warned area. Roadway flooding has been
reported in the Phoenixville area. This heavy rain in a short period
of time is also moving across central Montgomery County. Between 0.5
and 1 inch of rain has fallen in portions of the warned area. The
expected rainfall rate is 1 to 2.5 inches in 1 hour. Flash flooding
is already occurring.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Public reported.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
Some locations that may experience flash flooding include...
Philadelphia, Norristown, Phoenixville, Lansdale, West Norriton,
East Norriton, Perkasie, Doylestown, Conshohocken, Hatboro,
Souderton and Ambler.
This includes the following highways...
Interstate 476 in Pennsylvania between mile markers 12 and 19.
Interstate 76 in Pennsylvania between mile markers 327 and 334.
Northeast Extension between mile markers 21 and 36.
Pennsylvania Turnpike between mile markers 317 and 344.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4035 7537 4041 7530 4023 7498 4009 7522
4009 7523 4008 7524 4004 7530 3995 7553
4013 7561 4019 7555
FLASH FLOOD...OBSERVED
EXPECTED RAINFALL RATE...1-2.5 INCHES IN 1 HOUR
$$
Gorse422
WGUS71 KPHI 060419
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
1219 AM EDT Thu Aug 6 2026
PAC017-029-045-091-060515-
/O.CON.KPHI.FF.W.0103.000000T0000Z-260806T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Chester PA-Delaware PA-Montgomery PA-
1219 AM EDT Thu Aug 6 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 115 AM EDT EARLY THIS
MORNING FOR CENTRAL BUCKS, NORTHEASTERN CHESTER, NORTH CENTRAL
DELAWARE AND CENTRAL MONTGOMERY COUNTIES...
At 1219 AM EDT, the public reported thunderstorms produced heavy
rain earlier tonight across portions of the warned area. Rain is
tapering off, and additional amounts of up to 0.5 inches are
possible in the warned area. Roadway flooding has been reported in
the Phoenixville area. Flash flooding is occurring.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Public reported.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
Some locations that may experience flash flooding include...
Philadelphia, Norristown, Phoenixville, Lansdale, West Norriton,
East Norriton, Perkasie, Doylestown, Conshohocken, Hatboro,
Souderton and Ambler.
This includes the following highways...
Interstate 476 in Pennsylvania between mile markers 12 and 19.
Interstate 76 in Pennsylvania between mile markers 327 and 334.
Northeast Extension between mile markers 21 and 36.
Pennsylvania Turnpike between mile markers 317 and 344.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4035 7537 4041 7530 4023 7498 4009 7522
4009 7523 4008 7524 4004 7530 3995 7553
4013 7561 4019 7555
FLASH FLOOD...OBSERVED
$$
MPS090
WGUS71 KPHI 060505
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
105 AM EDT Thu Aug 6 2026
PAC017-029-045-091-060515-
/O.EXP.KPHI.FF.W.0103.000000T0000Z-260806T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Chester PA-Delaware PA-Montgomery PA-
105 AM EDT Thu Aug 6 2026
...FLASH FLOOD WARNING WILL EXPIRE AT 115 AM EDT EARLY THIS MORNING
FOR CENTRAL BUCKS, NORTHEASTERN CHESTER, NORTH CENTRAL DELAWARE AND
CENTRAL MONTGOMERY COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
&&
LAT...LON 4035 7537 4041 7530 4023 7498 4009 7522
4009 7523 4008 7524 4004 7530 3995 7553
4013 7561 4019 7555
$$
MPSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 5, 10:35 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 3 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 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.