Alert archive / Pennsylvania / Flash Flood Warnings in 2025

Flash Flood Warning 79, NWS Philadelphia/Mount Holly

July 31, 20254 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 31, 2025, 2:03 PM EDT for 4 counties in Pennsylvania. It was in force for 2 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
Jul 31, 2025, 2:03 PM EDT (18:03 UTC)
Expired
Jul 31, 2025, 4:25 PM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Berks County, PA, Bucks County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 104 km from the middle of the area, began a volume at 18:05 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 6.1 hours before the alert went out and 220 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, Brookhaven, NY at 12:00Z on 2025-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1000 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, Brookhaven, NY at 12:00Z on 2025-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -13 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
1000 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
970 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
-13 m²/s²
0-3 km storm-relative helicity
82 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

264 
WGUS51 KPHI 311803
FFWPHI
PAC011-017-077-091-312200-
/O.NEW.KPHI.FF.W.0079.250731T1803Z-250731T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
203 PM EDT Thu Jul 31 2025

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northeastern Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Northwestern Bucks County in southeastern Pennsylvania...
  Northeastern Montgomery County in southeastern Pennsylvania...

* Until 600 PM EDT.

* At 203 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 1.5 to 3 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...
  Allentown, Emmaus, Quakertown, Perkasie, Doylestown, Souderton, 
  Bedminster, Kutztown, Chalfont, Hatfield, East Greenville and 
  Dublin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4054 7534 4035 7499 4020 7516 4040 7557
      4058 7593 4070 7564

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1.5-3 INCHES IN 1 HOUR

$$

Kruzdlo
1 follow-up statement
296 
WGUS71 KPHI 312025
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
425 PM EDT Thu Jul 31 2025

PAC011-017-077-091-312035-
/O.CAN.KPHI.FF.W.0079.000000T0000Z-250731T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Bucks PA-Lehigh PA-Montgomery PA-
425 PM EDT Thu Jul 31 2025

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN BERKS, LEHIGH, 
NORTHWESTERN BUCKS AND NORTHEASTERN MONTGOMERY COUNTIES...

Although the heavy rain has ended, continue to heed any road 
closures that may be in effect due to earlier flooding.

A Flood Watch remains in effect until 600 AM EDT Friday for portions 
of Delaware, northeast Maryland, New Jersey, and Pennsylvania.

&&

LAT...LON 4054 7534 4035 7499 4020 7516 4040 7557
      4058 7593 4070 7564

$$

Kruzdlo

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 12:11 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Montgomery64 min
Jul 31, 12:19 PM EDTFlash Flood WarningPHIBerks4 hr
Jul 31, 12:53 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery67 min
Jul 31, 1:27 PM EDTFlash Flood WarningPHIBerks, Chester, Montgomery4 hr
Jul 31, 1:55 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery18 min
Jul 31, 2:05 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia40 min
Jul 31, 2:09 PM EDTFlash Flood Warning Considerable damage threatPHIDelaware4 hr
Jul 31, 2:27 PM EDTFlash Flood Warning Considerable damage threatPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Jul 31, 2:46 PM EDTFlash Flood Warning Considerable damage threatPHIDelaware4 hr
Jul 31, 2:55 PM EDTSevere Thunderstorm WarningPHIPhiladelphia50 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.