Alert archive / Pennsylvania / Flash Flood Warnings in 2026
Flash Flood Warning 38, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2026, 3:38 PM EDT for Chester County, Delaware County, Pennsylvania. It was in force for 4 hr. 8 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, 3:38 PM EDT (19:38 UTC)
- Expired
- Jul 9, 2026, 7:45 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Delaware County, PA
The radar
The Dover AFB radar (KDOX), 119 km from the middle of the area, began a volume at 19:38 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, 4:04 PM EDT | FLASH FLOOD | Oxford, PA | Market Street near Brick Road and South 5th Street flooded in Oxford. |
| Jul 9, 4:47 PM EDT | FLASH FLOOD | East Nottingham Twp., PA | Report of streams well over their banks and street flooding in East Nottingham Township near Oxford. |
| Jul 9, 5:30 PM EDT | RAIN 2.4 | 2 E East Nottingham Twp, PA | Mesonet station AV071 Oxford. |
| Jul 9, 5:30 PM EDT | RAIN 2.67 | 1 Ne Kaolin, PA | Mesonet station FW8290 Kennett Square. |
| Jul 9, 5:32 PM EDT | RAIN 2.36 | 1 Nne Penn Twp, PA | Mesonet station AV669 Cochranville. |
| Jul 9, 5:40 PM EDT | RAIN 3.44 | 1 Se New London Twp., PA | Mesonet station AU860 New London. |
| Jul 9, 5:54 PM EDT | RAIN 3.44 | New London Twp., PA | |
| Jul 9, 6:45 PM EDT | RAIN 3.51 | East Nottingham Twp., PA |
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, 7.6 hours before the alert went out and 158 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.
634
WGUS51 KPHI 091938
FFWPHI
PAC029-045-092345-
/O.NEW.KPHI.FF.W.0038.260709T1938Z-260709T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
338 PM EDT Thu Jul 9 2026
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Southern Chester County in southeastern Pennsylvania...
Southwestern Delaware County in southeastern Pennsylvania...
* Until 745 PM EDT.
* At 338 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between
0.5 and 1 inch of rain has fallen. The expected rainfall rate is 1
to 3 inches in 1 hour. Additional rainfall amounts of 1 to 3
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...
West Chester, Westtown, Downingtown, Kennett Square, Oxford, West
Grove, Marshallton, Cochranville, Elam, Homeville, Concordville
and Cheyney.
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 3983 7564 3972 7598 3973 7613 3974 7611
3973 7610 3975 7610 3976 7606 3980 7604
3980 7605 3981 7603 3983 7604 3983 7602
3985 7602 3985 7601 3987 7600 3987 7599
3990 7599 4006 7555 3987 7544
FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR
$$
Guzzo2 follow-up statements
578
WGUS71 KPHI 092047
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
447 PM EDT Thu Jul 9 2026
PAC029-045-092345-
/O.CON.KPHI.FF.W.0038.000000T0000Z-260709T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-
447 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM EDT THIS
EVENING FOR SOUTHERN CHESTER AND SOUTHWESTERN DELAWARE COUNTIES...
At 447 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between 1
and 3 inches of rain have fallen. The expected rainfall rate is 1 to
2 inches in 1 hour. Additional rainfall amounts of 1 to 2 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Radar and automated gauges.
IMPACT...Flooding of small creeks and streams, urban areas,
highways, streets, and underpasses as well as other
drainage and low lying areas.
Some locations that may experience flash flooding include...
West Chester, Westtown, Downingtown, Kennett Square, Oxford, West
Grove, Marshallton, Cochranville, Elam, Homeville, Concordville
and Cheyney.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 3983 7564 3972 7598 3973 7613 3974 7611
3973 7610 3975 7610 3976 7606 3980 7604
3980 7605 3981 7603 3983 7604 3983 7602
3985 7602 3985 7601 3987 7600 3987 7599
3990 7599 4006 7555 3987 7544
FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
Guzzo560
WGUS71 KPHI 092335
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
735 PM EDT Thu Jul 9 2026
PAC029-045-092345-
/O.EXP.KPHI.FF.W.0038.000000T0000Z-260709T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-
735 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING WILL EXPIRE AT 745 PM EDT THIS EVENING FOR
SOUTHERN CHESTER AND SOUTHWESTERN DELAWARE 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 for a portion of
southeast Pennsylvania.
&&
LAT...LON 3983 7564 3972 7598 3973 7613 3974 7611
3973 7610 3975 7610 3976 7606 3980 7604
3980 7605 3981 7603 3983 7604 3983 7602
3985 7602 3985 7601 3987 7600 3987 7599
3990 7599 4006 7555 3987 7544
$$
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, 3:20 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Montgomery | 3 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.