Alert archive / Pennsylvania / Flash Flood Warnings in 2025
Flash Flood Warning 7, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at May 16, 2025, 11:41 AM EDT for Chester County, Delaware County, Pennsylvania. It was in force for 4 hr. 4 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
- May 16, 2025, 11:41 AM EDT (15:41 UTC)
- Expired
- May 16, 2025, 3:45 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Delaware County, PA
The radar
The Philadelphia radar (KDIX), 104 km from the middle of the area, began a volume at 15:45 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 |
|---|---|---|---|
| May 16, 12:00 PM EDT | FLASH FLOOD | Caln Twp, PA | Water rescues reported in Caln Township and Thorndale. Time estimated. |
| May 16, 12:00 PM EDT | FLASH FLOOD | Modena, PA | Report of cars stuck and water rescues ongoing along Union Street in Chester County. |
| May 16, 12:15 PM EDT | FLASH FLOOD | West Chester, PA | Several water rescues reported around West Chester. Time estimated. |
| May 16, 2:45 PM EDT | FLASH FLOOD | 1 Nne Marshallton, PA | Downington (DWNP1) went into flood stage. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 3.7 hours before the alert went out and 189 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
- 657 J/kg
- Mixed-layer CIN
- -104 J/kg
- Mixed-layer LCL
- 781 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 33 m²/s²
- 0-3 km storm-relative helicity
- 31 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.9
The text
As transmitted.
991
WGUS51 KPHI 161541
FFWPHI
PAC029-045-161945-
/O.NEW.KPHI.FF.W.0007.250516T1541Z-250516T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1141 AM EDT Fri May 16 2025
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Central Chester County in southeastern Pennsylvania...
Central Delaware County in southeastern Pennsylvania...
* Until 345 PM EDT.
* At 1141 AM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. The expected rainfall rate is 2 to 4 inches in 1
hour. Additional rainfall amounts of 1 to 2 inches are possible in
the warned area. Flash flooding is ongoing or expected to begin
shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar.
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...
West Chester, Coatesville, Westtown, Downingtown, Marshallton,
Cheyney, Gradyville, Lima, Newtown Square, Radnor Township,
Broomall and Trout Lake.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4001 7577 4002 7572 4003 7555 4001 7532
3993 7543 3989 7548 3988 7567 3985 7577
3999 7584
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...2-4 INCHES IN 1 HOUR
$$
Kruzdlo3 follow-up statements
242
WGUS71 KPHI 161602
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
1202 PM EDT Fri May 16 2025
PAC029-045-161945-
/O.CON.KPHI.FF.W.0007.000000T0000Z-250516T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-
1202 PM EDT Fri May 16 2025
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 PM EDT THIS
AFTERNOON FOR CENTRAL CHESTER AND CENTRAL DELAWARE COUNTIES...
At 1202 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. The expected rainfall rate is 2 to 4 inches in 1 hour.
Additional rainfall amounts of 1 to 2 inches are possible in the
warned area. Flash flooding is ongoing or expected to begin shortly.
HAZARD...Life threatening flash flooding caused by thunderstorms.
SOURCE...Radar.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
Some locations that may experience flash flooding include...
West Chester, Coatesville, Westtown, Downingtown, Marshallton,
Cheyney, Gradyville, Lima, Newtown Square, Radnor Township,
Broomall and Trout Lake.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4001 7577 4002 7572 4003 7555 4001 7532
3993 7543 3989 7548 3988 7567 3985 7577
3999 7584
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...2-4 INCHES IN 1 HOUR
$$
Kruzdlo075
WGUS71 KPHI 161658
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
1258 PM EDT Fri May 16 2025
PAC029-045-161945-
/O.CON.KPHI.FF.W.0007.000000T0000Z-250516T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-
1258 PM EDT Fri May 16 2025
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 PM EDT THIS
AFTERNOON FOR CENTRAL CHESTER AND CENTRAL DELAWARE COUNTIES...
At 1258 PM EDT, Although the heavy rain has come to an end, water
rescues are ongoing from the Coatesville and Modena areas east to
West Chester.
HAZARD...Life threatening flash flooding caused by thunderstorms.
SOURCE...Trained Spotters and local law enforcement.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
Some locations that may experience flash flooding include...
West Chester, Coatesville, Westtown, Downingtown, Marshallton,
Cheyney, Gradyville, Lima, Newtown Square, Radnor Township,
Broomall and Trout Lake.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4001 7577 4002 7572 4003 7555 4001 7532
3993 7543 3989 7548 3988 7567 3985 7577
3999 7584
FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...2-4 INCHES IN 1 HOUR
$$
Kruzdlo665
WGUS71 KPHI 161941
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
341 PM EDT Fri May 16 2025
PAC029-045-161951-
/O.EXP.KPHI.FF.W.0007.000000T0000Z-250516T1945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-
341 PM EDT Fri May 16 2025
...FLASH FLOOD WARNING WILL EXPIRE AT 345 PM EDT THIS AFTERNOON FOR
CENTRAL CHESTER AND CENTRAL DELAWARE COUNTIES...
Flooding has ended or continues to recede. Please continue to heed
remaining road closures if you encounter any.
&&
LAT...LON 4001 7577 4002 7572 4003 7555 4001 7532
3993 7543 3989 7548 3988 7567 3985 7577
3999 7584
$$
KruzdloThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 9:34 PM EDT | Dense Fog Advisory | PHI | Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more | 12 hr |
| May 16, 10:24 AM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more | 66 min |
| May 16, 11:16 AM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 59 min |
| May 16, 11:22 AM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Montgomery, Philadelphia | 53 min |
| May 16, 11:32 AM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| May 16, 12:20 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 40 min |
| May 16, 12:21 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery | 4 hr |
| May 16, 2:02 PM EDT | River Flood Warning | PHI | Chester | 5 hr |
| May 16, 3:29 PM EDT | Areal Flood Warning | PHI | Berks | 6 hr |
| May 16, 3:53 PM EDT | Areal Flood Warning | PHI | Montgomery | 100 min |
| May 16, 4:42 PM EDT | Areal Flood Warning | PHI | Montgomery, Philadelphia | 4 hr |
| May 16, 5:15 PM EDT | Areal Flood Warning | PHI | Bucks | 112 min |
| May 16, 6:43 PM EDT | Areal Flood Warning | PHI | Philadelphia | 113 min |
Nearby
Flash Flood Warnings in Pennsylvania, 2025Every flash flood warning in 2025
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.