Alert archive / Pennsylvania / Flash Flood Warnings in 2025

Flash Flood Warning 40, NWS Philadelphia/Mount Holly

July 8, 2025Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 8, 2025, 5:02 PM EDT for Chester 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, 5:02 PM EDT (21:02 UTC)
Expired: Jul 8, 2025, 9:00 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 21:05 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
Jul 8, 5:07 PM EDT	FLASH FLOOD	1 Sw Chester Springs, PA	Video of several large trees snapped. Time estimated from radar.
Jul 8, 5:28 PM EDT	FLASH FLOOD	Coatesville, PA	Water rescue on Merchant St.

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, 9.0 hours before the alert went out and 185 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

770 
WGUS51 KPHI 082102
FFWPHI
PAC029-090100-
/O.NEW.KPHI.FF.W.0040.250708T2102Z-250709T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Central Chester County in southeastern Pennsylvania...

* Until 900 PM EDT.

* At 502 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. The expected rainfall rate is 2 to 3 inches in 1 hour. 
  Additional rainfall amounts of 1.5 to 2.5 inches are possible in 
  the warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  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...
  Phoenixville, Coatesville, Downingtown, Honey Brook, Glenmoore, 
  Lionville, Lionville-Marchwood, Chester Springs, Paoli, Malvern, 
  South Coatesville and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3997 7576 3998 7580 3998 7583 3997 7594
      3997 7599 4004 7594 4008 7594 4009 7592
      4011 7581 4013 7575 4014 7559 4012 7549
      4005 7548 3999 7558 3996 7571

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...2-3 INCHES IN 1 HOUR

$$

Hoeflich

3 follow-up statements

038 
WGUS71 KPHI 082135
FFSPHI

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

PAC029-090100-
/O.CON.KPHI.FF.W.0040.000000T0000Z-250709T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
535 PM EDT Tue Jul 8 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM EDT THIS EVENING 
FOR CENTRAL CHESTER COUNTY...

At 535 PM EDT, local law enforcement reported thunderstorms 
producing heavy rain with water rescues in Coatesville. Between 1.5 
and 2.5 inches of rain have fallen. The expected rainfall rate is 2 
to 3 inches in 1 hour. Additional rainfall amounts of 1 to 2 inches 
are possible in the warned area. Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Law enforcement 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...
  Phoenixville, Coatesville, Downingtown, Honey Brook, Glenmoore, 
  Lionville, Lionville-Marchwood, Chester Springs, Paoli, Malvern, 
  South Coatesville and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3997 7576 3998 7580 3998 7583 3997 7594
      3997 7599 4004 7594 4008 7594 4009 7592
      4011 7581 4013 7575 4014 7559 4012 7549
      4005 7548 3999 7558 3996 7571

FLASH FLOOD...OBSERVED
EXPECTED RAINFALL RATE...2-3 INCHES IN 1 HOUR

$$

Hoeflich

444 
WGUS71 KPHI 082319
FFSPHI

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

PAC029-090100-
/O.CON.KPHI.FF.W.0040.000000T0000Z-250709T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
719 PM EDT Tue Jul 8 2025

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 9 PM EDT THIS EVENING 
FOR CENTRAL CHESTER COUNTY...

At 719 PM EDT, local law enforcement reported thunderstorms 
producing heavy rain with water rescues in Coatesville. 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...Law enforcement 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...
  Phoenixville, Coatesville, Downingtown, Honey Brook, Glenmoore, 
  Lionville, Lionville-Marchwood, Chester Springs, Paoli, Malvern, 
  South Coatesville and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Move to higher ground now. Act quickly to protect your life.

&&

LAT...LON 3997 7576 3998 7580 3998 7583 3997 7594
      3997 7599 4004 7594 4008 7594 4009 7592
      4011 7581 4013 7575 4014 7559 4012 7549
      4005 7548 3999 7558 3996 7571

FLASH FLOOD...OBSERVED

$$

Hoeflich

506 
WGUS71 KPHI 090054
FFSPHI

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

PAC029-090104-
/O.EXP.KPHI.FF.W.0040.000000T0000Z-250709T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-
854 PM EDT Tue Jul 8 2025

...FLASH FLOOD WARNING WILL EXPIRE AT 9 PM EDT THIS EVENING FOR 
CENTRAL CHESTER COUNTY...

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 3997 7576 3998 7580 3998 7583 3997 7594
      3997 7599 4004 7594 4008 7594 4009 7592
      4011 7581 4013 7575 4014 7559 4012 7549
      4005 7548 3999 7558 3996 7571

$$

Hoeflich

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 10:59 PM EDT	Flood Watch	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	23 hr
Jul 8, 3:04 PM EDT	Severe Thunderstorm Warning	PHI	Berks	41 min
Jul 8, 3:44 PM EDT	Severe Thunderstorm Warning	PHI	Berks	46 min
Jul 8, 4:05 PM EDT	Flash Flood Warning	PHI	Berks	4 hr
Jul 8, 4:20 PM EDT	Severe Thunderstorm Warning	PHI	Chester	40 min
Jul 8, 4:25 PM EDT	Severe Thunderstorm Warning	PHI	Berks	35 min
Jul 8, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Montgomery	42 min
Jul 8, 4:39 PM EDT	Flash Flood Warning	PHI	Chester	4 hr
Jul 8, 4:54 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Berks, Chester, Montgomery	51 min
Jul 8, 4:56 PM EDT	Severe Thunderstorm Warning	PHI	Chester	19 min
Jul 8, 5:16 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	29 min
Jul 8, 5:19 PM EDT	Tornado Warning	PHI	Bucks, Montgomery	26 min
Jul 8, 5:20 PM EDT	Tornado Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	25 min
Jul 8, 5:31 PM EDT	Flash Flood Warning	PHI	Chester, Delaware	4 hr
Jul 8, 5:34 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Bucks, Delaware, Montgomery, Philadelphia	41 min
Jul 8, 5:45 PM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	4 hr
Jul 8, 5:46 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	44 min
Jul 8, 5:52 PM EDT	Tornado Warning	PHI	Bucks, Montgomery, Philadelphia	13 min
Jul 8, 5:53 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery, Philadelphia	4 hr
Jul 8, 5:56 PM EDT	Severe Thunderstorm Warning Considerable damage threat	PHI	Bucks, Philadelphia	49 min
Jul 8, 6:08 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	34 min

Nearby

Flash Flood Warnings in Pennsylvania, 2025 Every 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.