Alert archive / Pennsylvania / Flash Flood Warnings in 2025

Flash Flood Warning 21, NWS Philadelphia/Mount Holly

June 26, 2025New Castle County, Delaware; Chester County, Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 26, 2025, 7:27 PM EDT for New Castle County, Delaware; Chester County, Delaware County, Pennsylvania. It was in force for 4 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jun 26, 2025, 7:27 PM EDT (23:27 UTC)
Expired
Jun 26, 2025, 11:30 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), 115 km from the middle of the area, began a volume at 23:29 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.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.5 hours before the alert went out and 159 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 2025-06-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 437 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 2025-06-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -18 square meters per square second.1939Sfc1 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
437 J/kg
Mixed-layer CIN
-110 J/kg
Mixed-layer LCL
1094 m above ground
0-6 km bulk shear
3 kt
0-1 km storm-relative helicity
-18 m²/s²
0-3 km storm-relative helicity
17 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

828 
WGUS51 KPHI 262327
FFWPHI
DEC003-PAC029-045-270330-
/O.NEW.KPHI.FF.W.0021.250626T2327Z-250627T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
727 PM EDT Thu Jun 26 2025

The National Weather Service in Mount Holly has issued a

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

* Until 1130 PM EDT.

* At 727 PM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.5 and 2 inches of rain have fallen. Additional rainfall amounts 
  of 0.5 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 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...
  Wilmington, Newark, Coatesville, Elsmere, Kennett Square, New 
  Castle, Oxford, Parkesburg, West Grove, Newport, Arden and 
  Landenberg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most 
flood deaths occur in vehicles.

&&

LAT...LON 3975 7610 3976 7608 3976 7606 3983 7604
      3983 7602 3985 7602 3987 7599 3993 7600
      3993 7598 3995 7599 4006 7592 3985 7550
      3975 7549 3969 7552 3961 7560 3963 7579
      3972 7579 3972 7612 3973 7609

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

SFJ
2 follow-up statements
807 
WGUS71 KPHI 270032
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
832 PM EDT Thu Jun 26 2025

DEC003-PAC029-045-270330-
/O.CON.KPHI.FF.W.0021.000000T0000Z-250627T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
832 PM EDT Thu Jun 26 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1130 PM EDT THIS 
EVENING FOR NORTHWESTERN NEW CASTLE, SOUTHWESTERN CHESTER AND 
SOUTHWESTERN DELAWARE COUNTIES...

At 832 PM EDT, Doppler radar and automated rain gauges indicated the 
thunderstorms that had produced the heaviest rain had left the 
warned area. However, additional light rain could exacerbate any 
ongoing flooding. Between 0.5 and 2.5 inches of rain have fallen. 
Additional rainfall amounts up to 0.5 inches are possible in the 
warned area. 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...
  Wilmington, Newark, Coatesville, Elsmere, Kennett Square, New 
  Castle, Oxford, Parkesburg, West Grove, Newport, Arden and 
  Landenberg.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3975 7610 3976 7608 3976 7606 3983 7604
      3983 7602 3985 7602 3987 7599 3993 7600
      3993 7598 3995 7599 4006 7592 3985 7550
      3975 7549 3969 7552 3961 7560 3963 7579
      3972 7579 3972 7612 3973 7609

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

SFJ
757 
WGUS71 KPHI 270325
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1125 PM EDT Thu Jun 26 2025

DEC003-PAC029-045-270335-
/O.EXP.KPHI.FF.W.0021.000000T0000Z-250627T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
1125 PM EDT Thu Jun 26 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 1130 PM EDT THIS EVENING FOR 
NORTHWESTERN NEW CASTLE, SOUTHWESTERN CHESTER AND SOUTHWESTERN 
DELAWARE COUNTIES...

The heavy rain has ended. Flash flooding is no longer expected to 
pose a threat. Rivers may continue to rise as runoff continues. 
Please continue to heed remaining road closures.

&&

LAT...LON 3975 7610 3976 7608 3976 7606 3983 7604
      3983 7602 3985 7602 3987 7599 3993 7600
      3993 7598 3995 7599 4006 7592 3985 7550
      3975 7549 3969 7552 3961 7560 3963 7579
      3972 7579 3972 7612 3973 7609

$$

AKL

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 26, 4:25 AM EDTCoastal Flood AdvisoryPHIKent, New Castle, Sussex23 hr
Jun 26, 2:05 PM EDTSevere Thunderstorm WarningPHISussex40 min
Jun 26, 7:14 PM EDTSevere Thunderstorm WarningPHINew Castle46 min
Jun 26, 12:24 PM EDTFlood WatchPHIBerks, Carbon, Chester, Lehigh11 hr
Jun 26, 3:48 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh42 min
Jun 26, 4:20 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton40 min
Jun 26, 4:31 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery44 min
Jun 26, 5:45 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery45 min
Jun 26, 6:21 PM EDTFlash Flood WarningPHIBerks2 hr
Jun 26, 6:29 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Delaware, Montgomery46 min
Jun 26, 6:49 PM EDTFlash Flood WarningPHIChester, Delaware4 hr
Jun 26, 6:54 PM EDTSevere Thunderstorm WarningPHIChester36 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.