Alert archive / Pennsylvania / Flash Flood Warnings in 2026
Flash Flood Warning 37, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2026, 3:20 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 3 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 9, 2026, 3:20 PM EDT (19:20 UTC)
- Expired
- Jul 9, 2026, 5:55 PM EDT
- In force
- 3 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), 118 km from the middle of the area, began a volume at 19:19 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 9, 3:37 PM EDT | FLASH FLOOD | 1 W Sanatoga, PA | East High Street closed near Porter Road due to high water. PennDOT vehicles are on the scene to direct traffic. |
| Jul 9, 3:57 PM EDT | FLASH FLOOD | 1 Sw Stowe, PA | Report from mPING: Street/road flooding; Street/road closed; Vehicles stranded. |
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, 7.3 hours before the alert went out and 195 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
- 1170 J/kg
- Mixed-layer CIN
- -24 J/kg
- Mixed-layer LCL
- 543 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 39 m²/s²
- 0-3 km storm-relative helicity
- 49 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted.
932
WGUS51 KPHI 091920
FFWPHI
PAC011-029-091-092330-
/O.NEW.KPHI.FF.W.0037.260709T1920Z-260709T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
320 PM EDT Thu Jul 9 2026
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...
Northwestern Montgomery County in southeastern Pennsylvania...
* Until 730 PM EDT.
* At 320 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. The expected rainfall rate
is 1 to 2 inches in 1 hour. 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...
Pottstown, Phoenixville, West Norriton, East Norriton, Birdsboro,
Collegeville, Royersford, Trappe, Honey Brook, Schwenksville,
Elverson and Green Lane.
This includes the following highways...
Interstate 176 in Pennsylvania between mile markers 1 and 6.
Pennsylvania Turnpike between mile markers 296 and 309.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 4037 7547 4015 7537 4004 7593 4004 7594
4008 7594 4011 7594 4014 7587 4022 7600
FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
Guzzo2 follow-up statements
611
WGUS71 KPHI 092045
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
445 PM EDT Thu Jul 9 2026
PAC011-029-091-092330-
/O.CON.KPHI.FF.W.0037.000000T0000Z-260709T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Chester PA-Montgomery PA-
445 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 730 PM EDT THIS
EVENING FOR SOUTHEASTERN BERKS, NORTHEASTERN CHESTER AND
NORTHWESTERN MONTGOMERY COUNTIES...
At 445 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain in Pottstown. Between 1 and 2.5
inches of rain have fallen. Additional rainfall amounts up to 0.5
inches are possible in the warned area. Flash flooding is already
occurring.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar and automated gauges.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
Some locations that may experience flash flooding include...
Pottstown, Phoenixville, West Norriton, East Norriton, Birdsboro,
Collegeville, Royersford, Trappe, Honey Brook, Schwenksville,
Elverson and Green Lane.
This includes the following highways...
Interstate 176 in Pennsylvania between mile markers 1 and 6.
Pennsylvania Turnpike between mile markers 296 and 309.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 4037 7547 4015 7537 4004 7593 4004 7594
4008 7594 4011 7594 4014 7587 4022 7600
FLASH FLOOD...RADAR AND GAUGE INDICATED
$$
Guzzo573
WGUS71 KPHI 092155
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
555 PM EDT Thu Jul 9 2026
PAC011-029-091-092205-
/O.CAN.KPHI.FF.W.0037.000000T0000Z-260709T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Chester PA-Montgomery PA-
555 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN BERKS,
NORTHEASTERN CHESTER AND NORTHWESTERN MONTGOMERY COUNTIES...
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.
A Flood Watch remains in effect until 1200 AM EDT Friday for a
portion of southeast Pennsylvania.
&&
LAT...LON 4037 7547 4015 7537 4004 7593 4004 7594
4008 7594 4011 7594 4014 7587 4022 7600
$$
GuzzoThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 9, 2:09 AM EDT | Flood Watch | PHI | Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia | 19 hr |
| Jul 9, 1:37 PM EDT | Flash Flood Warning | PHI | Delaware | 6 hr |
| Jul 9, 2:00 PM EDT | Flash Flood Warning | PHI | Delaware, Philadelphia | 5 hr |
| Jul 9, 3:01 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Jul 9, 3:38 PM EDT | Flash Flood Warning | PHI | Chester, Delaware | 4 hr |
| Jul 9, 4:30 PM EDT | Flash Flood Warning | PHI | Chester, Delaware | 4 hr |
| Jul 9, 5:30 PM EDT | Severe Thunderstorm Warning | PHI | Delaware | 45 min |
Nearby
Flash Flood Warnings in Pennsylvania, 2026Every flash flood warning in 2026
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.