Alert archive / Pennsylvania / Flash Flood Warnings in 2025
Flash Flood Warning 8, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at May 16, 2025, 12:21 PM EDT for Bucks County, Montgomery 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
- May 16, 2025, 12:21 PM EDT (16:21 UTC)
- Expired
- May 16, 2025, 4:30 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Bucks County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 80 km from the middle of the area, began a volume at 16:25 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 |
|---|---|---|---|
| May 16, 12:55 PM EDT | FLASH FLOOD | Lansdale, PA | Picture of significant flooding around Lansdale. Time estimated. |
| May 16, 1:45 PM EDT | FLASH FLOOD | 1 E Schwenksville, PA | SWVP1 went into flood stage. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 4.4 hours before the alert went out and 213 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 572 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 32 m²/s²
- 0-3 km storm-relative helicity
- 40 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
080
WGUS51 KPHI 161621
FFWPHI
PAC017-091-162030-
/O.NEW.KPHI.FF.W.0008.250516T1621Z-250516T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1221 PM EDT Fri May 16 2025
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Southwestern Bucks County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
* Until 430 PM EDT.
* At 1221 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 4 inches in 1 hour.
Additional rainfall amounts of 0.5 to 1.5 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...
Lansdale, Hatboro, Souderton, Chalfont, Hatfield, Bryn Athyn,
Ivyland, Fricks, Willow Grove, Richboro, Horsham and Skippack.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4034 7531 4021 7495 4014 7511 4023 7545
4032 7542
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...2-4 INCHES IN 1 HOUR
$$
Kruzdlo2 follow-up statements
623
WGUS71 KPHI 161718
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
118 PM EDT Fri May 16 2025
PAC017-091-162030-
/O.CON.KPHI.FF.W.0008.000000T0000Z-250516T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Montgomery PA-
118 PM EDT Fri May 16 2025
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM EDT THIS
AFTERNOON FOR SOUTHWESTERN BUCKS AND CENTRAL MONTGOMERY COUNTIES...
At 118 PM EDT, Although the heavy rain has ended, local law
enforcement significant flooding in the Landsdale area.
HAZARD...Life threatening flash flooding caused by thunderstorms.
SOURCE...Law enforcement reported.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
Some locations that may experience flash flooding include...
Lansdale, Hatboro, Souderton, Chalfont, Hatfield, Bryn Athyn,
Ivyland, Fricks, Willow Grove, Richboro, Horsham and Skippack.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4034 7531 4021 7495 4014 7511 4023 7545
4032 7542
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...2-4 INCHES IN 1 HOUR
$$
Kruzdlo540
WGUS71 KPHI 162021
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
421 PM EDT Fri May 16 2025
PAC017-091-162031-
/O.EXP.KPHI.FF.W.0008.000000T0000Z-250516T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Montgomery PA-
421 PM EDT Fri May 16 2025
...FLASH FLOOD WARNING WILL EXPIRE AT 430 PM EDT THIS AFTERNOON FOR
SOUTHWESTERN BUCKS AND CENTRAL MONTGOMERY COUNTIES...
Flooding has ended or continues to recede. Please continue to heed
remaining road closures if you encounter any.
&&
LAT...LON 4034 7531 4021 7495 4014 7511 4023 7545
4032 7542
$$
KruzdloThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 15, 9:34 PM EDT | Dense Fog Advisory | PHI | Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more | 12 hr |
| May 16, 10:24 AM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Carbon, Chester, Lehigh, Monroe and 2 more | 66 min |
| May 16, 11:16 AM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 59 min |
| May 16, 11:22 AM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Montgomery, Philadelphia | 53 min |
| May 16, 11:32 AM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| May 16, 11:41 AM EDT | Flash Flood Warning | PHI | Chester, Delaware | 4 hr |
| May 16, 12:20 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 40 min |
| May 16, 2:02 PM EDT | River Flood Warning | PHI | Chester | 5 hr |
| May 16, 3:29 PM EDT | Areal Flood Warning | PHI | Berks | 6 hr |
| May 16, 3:53 PM EDT | Areal Flood Warning | PHI | Montgomery | 100 min |
| May 16, 4:42 PM EDT | Areal Flood Warning | PHI | Montgomery, Philadelphia | 4 hr |
| May 16, 5:15 PM EDT | Areal Flood Warning | PHI | Bucks | 112 min |
| May 16, 6:43 PM EDT | Areal Flood Warning | PHI | Philadelphia | 113 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.