Alert archive / Pennsylvania / Flash Flood Warnings in 2025

Flash Flood Warning 41, NWS Philadelphia/Mount Holly

July 8, 2025New Castle County, Delaware; Chester County, Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 8, 2025, 5:31 PM EDT for New Castle County, Delaware; Chester County, Delaware County, Pennsylvania. It was in force for 4 hr. 2 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
Jul 8, 2025, 5:31 PM EDT (21:31 UTC)
Expired
Jul 8, 2025, 9:45 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties New Castle County, DE, Chester County, PA, Delaware County, PA

The radar

The Dover AFB radar (KDOX), 117 km from the middle of the area, began a volume at 21:30 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

TimeReportWhereRemark
Jul 8, 5:57 PM EDTFLASH FLOODNottingham, PAFlooding on roadways in Nottingham.
Jul 8, 6:00 PM EDTFLASH FLOOD1 Wnw Oxford, PAOxford Exit on Route 1 flooded out. Time given in report.

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, 9.5 hours before the alert went out and 163 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.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2025-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 695 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2025-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
695 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
1207 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

640 
WGUS51 KPHI 082131
FFWPHI
DEC003-PAC029-045-090145-
/O.NEW.KPHI.FF.W.0041.250708T2131Z-250709T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
531 PM EDT Tue Jul 8 2025

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northwestern New Castle County in northern Delaware...
  Southern Chester County in southeastern Pennsylvania...
  Southwestern Delaware County in southeastern Pennsylvania...

* Until 945 PM EDT.

* At 531 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 1 inch of rain has 
  fallen. The expected rainfall rate is 2.5 to 3.5 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, Westtown, Kennett Square, Oxford, West Grove, 
  Landenberg, Hockessin, North Star, Ashland, Pike Creek, 
  Kemblesville and Marshallton.

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 3989 7578 3992 7574 3997 7572 4000 7558
      3996 7554 3991 7552 3978 7554 3973 7572
      3972 7614 3973 7612 3974 7611 3973 7610
      3973 7609 3975 7610 3974 7609 3976 7608
      3978 7604 3981 7590

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...2.5-3.5 INCHES IN 1 HOUR

$$

Hoeflich
3 follow-up statements
325 
WGUS71 KPHI 082213
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
613 PM EDT Tue Jul 8 2025

DEC003-PAC029-045-090145-
/O.CON.KPHI.FF.W.0041.000000T0000Z-250709T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
613 PM EDT Tue Jul 8 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM EDT THIS 
EVENING FOR NORTHWESTERN NEW CASTLE, SOUTHERN CHESTER AND 
SOUTHWESTERN DELAWARE COUNTIES...

At 613 PM EDT, trained weather spotters reported thunderstorms 
producing heavy rain in Oxford and Nottingham with numerous flooded 
roadways reported. Between 2 and 3 inches of rain have fallen. The 
expected rainfall rate is 2.5 to 3.5 inches in 1 hour. Additional 
rainfall amounts of 0.5 to 1.5 inches are possible in the warned 
area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters 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...
  West Chester, Westtown, Kennett Square, Oxford, West Grove, 
  Landenberg, Hockessin, North Star, Ashland, Pike Creek, 
  Kemblesville and Marshallton.

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 3989 7578 3992 7574 3997 7572 4000 7558
      3996 7554 3991 7552 3978 7554 3973 7572
      3972 7614 3973 7612 3974 7611 3973 7610
      3973 7609 3975 7610 3974 7609 3976 7608
      3978 7604 3981 7590

FLASH FLOOD...OBSERVED
EXPECTED RAINFALL RATE...2.5-3.5 INCHES IN 1 HOUR

$$

Hoeflich
663 
WGUS71 KPHI 082320
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
720 PM EDT Tue Jul 8 2025

DEC003-PAC029-045-090145-
/O.CON.KPHI.FF.W.0041.000000T0000Z-250709T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
720 PM EDT Tue Jul 8 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM EDT THIS 
EVENING FOR NORTHWESTERN NEW CASTLE, SOUTHERN CHESTER AND 
SOUTHWESTERN DELAWARE COUNTIES...

At 720 PM EDT, trained weather spotters reported thunderstorms 
producing heavy rain in Oxford and Nottingham with numerous flooded 
roadways reported. Between 1.5 and 3 inches of rain have fallen. 
Flooding impacts will continue, but no additional rainfall is 
expected. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Trained spotters 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...
  West Chester, Westtown, Kennett Square, Oxford, West Grove, 
  Landenberg, Hockessin, North Star, Ashland, Pike Creek, 
  Kemblesville and Marshallton.

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 3989 7578 3992 7574 3997 7572 4000 7558
      3996 7554 3991 7552 3978 7554 3973 7572
      3972 7614 3973 7612 3974 7611 3973 7610
      3973 7609 3975 7610 3974 7609 3976 7608
      3978 7604 3981 7590

FLASH FLOOD...OBSERVED

$$

Hoeflich
784 
WGUS71 KPHI 090137
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
937 PM EDT Tue Jul 8 2025

DEC003-PAC029-045-090147-
/O.EXP.KPHI.FF.W.0041.000000T0000Z-250709T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
937 PM EDT Tue Jul 8 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 945 PM EDT THIS EVENING FOR 
NORTHWESTERN NEW CASTLE, SOUTHERN CHESTER AND SOUTHWESTERN DELAWARE 
COUNTIES...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

&&

LAT...LON 3989 7578 3992 7574 3997 7572 4000 7558
      3996 7554 3991 7552 3978 7554 3973 7572
      3972 7614 3973 7612 3974 7611 3973 7610
      3973 7609 3975 7610 3974 7609 3976 7608
      3978 7604 3981 7590

$$

Hoeflich

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 10:59 PM EDTFlood WatchPHIKent, New Castle, Sussex23 hr
Jul 8, 5:45 PM EDTFlash Flood WarningPHINew Castle4 hr
Jul 8, 5:45 PM EDTSevere Thunderstorm WarningPHIKent, New Castle60 min
Jul 8, 6:54 PM EDTSevere Thunderstorm WarningPHIKent, Sussex66 min
Jul 8, 7:28 PM EDTSevere Thunderstorm WarningPHISussex47 min
Jul 8, 3:04 PM EDTSevere Thunderstorm WarningPHIBerks41 min
Jul 8, 3:44 PM EDTSevere Thunderstorm WarningPHIBerks46 min
Jul 8, 4:05 PM EDTFlash Flood WarningPHIBerks4 hr
Jul 8, 4:20 PM EDTSevere Thunderstorm WarningPHIChester40 min
Jul 8, 4:25 PM EDTSevere Thunderstorm WarningPHIBerks35 min
Jul 8, 4:33 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery42 min
Jul 8, 4:39 PM EDTFlash Flood WarningPHIChester4 hr
Jul 8, 4:54 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIBerks, Chester, Montgomery51 min
Jul 8, 4:56 PM EDTSevere Thunderstorm WarningPHIChester19 min
Jul 8, 5:02 PM EDTFlash Flood WarningPHIChester4 hr
Jul 8, 5:16 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIBucks, Chester, Delaware, Montgomery, Philadelphia29 min
Jul 8, 5:19 PM EDTTornado WarningPHIBucks, Montgomery26 min
Jul 8, 5:20 PM EDTTornado WarningPHIChester, Delaware, Montgomery, Philadelphia25 min
Jul 8, 5:34 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIBucks, Delaware, Montgomery, Philadelphia41 min
Jul 8, 5:46 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia44 min
Jul 8, 5:52 PM EDTTornado WarningPHIBucks, Montgomery, Philadelphia13 min
Jul 8, 5:53 PM EDTFlash Flood WarningPHIBucks, Montgomery, Philadelphia4 hr
Jul 8, 5:56 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIBucks, Philadelphia49 min
Jul 8, 6:08 PM EDTSevere Thunderstorm WarningPHIBucks34 min

Nearby

Flash Flood Warnings in Pennsylvania, 2025Flash Flood Warnings in Delaware, 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.