Alert archive / Pennsylvania / Flash Flood Warnings in 2025
Flash Flood Warning 77, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 31, 2025, 1:27 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 4 hr. 1 report 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 31, 2025, 1:27 PM EDT (17:27 UTC)
- Expired
- Jul 31, 2025, 5:30 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Berks County, PA, Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 96 km from the middle of the area, began a volume at 17:31 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 31, 1:35 PM EDT | RAIN 2.42 | Colebrookdale Twp, PA | 2.42 inches in 1 hour. |
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, 5.5 hours before the alert went out and 205 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
- 1355 J/kg
- Mixed-layer CIN
- -40 J/kg
- Mixed-layer LCL
- 875 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 30 m²/s²
- 0-3 km storm-relative helicity
- 30 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.7
The text
As transmitted.
798
WGUS51 KPHI 311727
FFWPHI
PAC011-029-091-312130-
/O.NEW.KPHI.FF.W.0077.250731T1727Z-250731T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
127 PM EDT Thu Jul 31 2025
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Southeastern Berks County in eastern Pennsylvania...
Northeastern Chester County in southeastern Pennsylvania...
Montgomery County in southeastern Pennsylvania...
* Until 530 PM EDT.
* At 127 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. 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...
West Chester, Norristown, Pottstown, Phoenixville, Lansdale, West
Norriton, East Norriton, Westtown, Downingtown, Conshohocken,
Souderton and Ambler.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Please report observed flooding to local emergency services or law
enforcement and request they pass this information to the National
Weather Service when you can do so safely.
&&
LAT...LON 4032 7577 4047 7558 4021 7513 4005 7534
4007 7536 4004 7541 4003 7540 3999 7545
3999 7544 3994 7552 3992 7552 3993 7554
3990 7556 4023 7601
FLASH FLOOD...RADAR INDICATED
$$
MPS1 follow-up statement
791
WGUS71 KPHI 312122
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
522 PM EDT Thu Jul 31 2025
PAC011-029-091-312132-
/O.EXP.KPHI.FF.W.0077.000000T0000Z-250731T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Chester PA-Montgomery PA-
522 PM EDT Thu Jul 31 2025
...FLASH FLOOD WARNING WILL EXPIRE AT 530 PM EDT THIS AFTERNOON FOR
SOUTHEASTERN BERKS, NORTHEASTERN CHESTER AND MONTGOMERY COUNTIES...
Although the heavy rain has ended, continue to heed any road
closures that may be in effect due to earlier flooding.
A Flood Watch remains in effect until 600 AM EDT Friday for portions
of northern Delaware, New Jersey, and southeast Pennsylvania.
&&
LAT...LON 4032 7577 4047 7558 4021 7513 4005 7534
4007 7536 4004 7541 4003 7540 3999 7545
3999 7544 3994 7552 3992 7552 3993 7554
3990 7556 4023 7601
$$
MPSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 31, 12:11 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Montgomery | 64 min |
| Jul 31, 12:19 PM EDT | Flash Flood Warning | PHI | Berks | 4 hr |
| Jul 31, 12:53 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery | 67 min |
| Jul 31, 1:55 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery | 18 min |
| Jul 31, 2:03 PM EDT | Flash Flood Warning | PHI | Berks, Bucks, Lehigh, Montgomery | 2 hr |
| Jul 31, 2:05 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 40 min |
| Jul 31, 2:09 PM EDT | Flash Flood Warning | PHI | Delaware | 4 hr |
| Jul 31, 2:27 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Jul 31, 2:46 PM EDT | Flash Flood Warning | PHI | Delaware | 4 hr |
| Jul 31, 2:55 PM EDT | Severe Thunderstorm Warning | PHI | Philadelphia | 50 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.