Alert archive / Pennsylvania / Flash Flood Warnings in 2026
Flash Flood Warning 39, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 9, 2026, 4:30 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 4 hr. 5 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, 4:30 PM EDT (20:30 UTC)
- Expired
- Jul 9, 2026, 8:30 PM EDT
- In force
- 4 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties New Castle County, DE, Chester County, PA, Delaware County, PA
The radar
The Philadelphia radar (KDIX), 108 km from the middle of the area, began a volume at 20:33 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, 5:20 PM EDT | FLASH FLOOD | 1 Ssw Ashland, DE | Water rescue at Brackenville Road and Skyline Orchard Drive in Hockessin. Vehicle stuck in rapidly rising floodwater. Multiple roads impassible in the area. |
| Jul 9, 5:30 PM EDT | RAIN 2.67 | 1 Ne Kaolin, PA | Mesonet station FW8290 Kennett Square. |
| Jul 9, 8:00 PM EDT | RAIN 1.06 | White Clay Creek, DE | |
| Jul 9, 8:00 PM EDT | RAIN 2.38 | Greenville, DE | |
| Jul 9, 8:00 PM EDT | RAIN 3.65 | Hockessin, DE |
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, 8.5 hours before the alert went out and 177 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.
100
WGUS51 KPHI 092030
FFWPHI
DEC003-PAC029-045-100030-
/O.NEW.KPHI.FF.W.0039.260709T2030Z-260710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
430 PM EDT Thu Jul 9 2026
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Northwestern New Castle County in northern Delaware...
South Central Chester County in southeastern Pennsylvania...
Southwestern Delaware County in southeastern Pennsylvania...
* Until 830 PM EDT.
* At 430 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...
Newark, Chester, Swarthmore, Arden, Talleyville, Greenville, Elam,
Ashland, Concordville, Hockessin, Chelsea and Pike Creek.
This includes Interstate 476 in Pennsylvania between mile markers 1
and 6.
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 3989 7557 3998 7536 3989 7531 3982 7547
3968 7579 3972 7579 3972 7591 3972 7595
3972 7596
FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR
$$
Guzzo4 follow-up statements
311
WGUS71 KPHI 092116
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
516 PM EDT Thu Jul 9 2026
DEC003-PAC029-045-100030-
/O.CON.KPHI.FF.W.0039.000000T0000Z-260710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
516 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM EDT THIS
EVENING FOR NORTHWESTERN NEW CASTLE, SOUTH CENTRAL CHESTER AND
SOUTHWESTERN DELAWARE COUNTIES...
At 516 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between 1
and 3 inches of rain have fallen. The expected rainfall rate is 1 to
3 inches in 1 hour. Additional rainfall amounts of 1 to 3 inches are
possible in the warned area. Flash flooding is ongoing or expected
to begin shortly.
HAZARD...Life threatening flash flooding caused by thunderstorms.
SOURCE...Radar and automated gauges.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
Some locations that may experience flash flooding include...
Newark, Chester, Swarthmore, Arden, Talleyville, Greenville, Elam,
Ashland, Concordville, Hockessin, Chelsea and Pike Creek.
This includes Interstate 476 in Pennsylvania between mile markers 1
and 6.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 3989 7557 3998 7536 3989 7531 3982 7547
3968 7579 3972 7579 3972 7591 3972 7595
3972 7596
FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR
$$
Guzzo089
WGUS71 KPHI 092129
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
529 PM EDT Thu Jul 9 2026
DEC003-PAC029-045-100030-
/O.CON.KPHI.FF.W.0039.000000T0000Z-260710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
529 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM EDT THIS
EVENING FOR NORTHWESTERN NEW CASTLE, SOUTH CENTRAL CHESTER AND
SOUTHWESTERN DELAWARE COUNTIES...
At 529 PM EDT, emergency management reported flash flooding
occurring in Hockessin. Between 1 and 3 inches of rain have 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 already occurring.
HAZARD...Life threatening flash flooding caused by thunderstorms.
SOURCE...Emergency management reported.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
Some locations that may experience flash flooding include...
Newark, Chester, Swarthmore, Arden, Talleyville, Greenville, Elam,
Ashland, Concordville, Hockessin, Chelsea and Pike Creek.
This includes Interstate 476 in Pennsylvania between mile markers 1
and 6.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
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 3989 7557 3998 7536 3989 7531 3982 7547
3968 7579 3972 7579 3972 7591 3972 7595
3972 7596
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR
$$
Guzzo779
WGUS71 KPHI 092342
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
742 PM EDT Thu Jul 9 2026
DEC003-PAC029-045-100030-
/O.CON.KPHI.FF.W.0039.000000T0000Z-260710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
742 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM EDT THIS
EVENING FOR NORTHWESTERN NEW CASTLE, SOUTH CENTRAL CHESTER AND
SOUTHWESTERN DELAWARE COUNTIES...
At 742 PM EDT, emergency management reported flash flooding
occurring in Hockessin. Between 1.5 and 4 inches of rain have
fallen. Additional rainfall amounts up to 0.5 inches are possible in
the warned area. Flash flooding is already occurring.
HAZARD...Life threatening flash flooding caused by thunderstorms.
SOURCE...Emergency management reported.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
Some locations that may experience flash flooding include...
Newark, Chester, Swarthmore, Arden, Ashland, Greenville,
Hockessin, Talleyville, Pike Creek, North Star, Elam and
Landenberg.
This includes Interstate 476 in Pennsylvania near mile marker 1.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be aware of your surroundings and do not drive on flooded roads.
In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.
&&
LAT...LON 3972 7591 3972 7595 3988 7559 3989 7557
3989 7531 3968 7579 3972 7579
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
Guzzo101
WGUS71 KPHI 100023
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
823 PM EDT Thu Jul 9 2026
DEC003-PAC029-045-100033-
/O.EXP.KPHI.FF.W.0039.000000T0000Z-260710T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
823 PM EDT Thu Jul 9 2026
...FLASH FLOOD WARNING WILL EXPIRE AT 830 PM EDT THIS EVENING FOR
NORTHWESTERN NEW CASTLE, SOUTH CENTRAL 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.
A Flood Watch remains in effect until 1200 AM EDT for portions of
northern Delaware and southern New Jersey.
&&
LAT...LON 3972 7591 3972 7595 3988 7559 3989 7557
3989 7531 3968 7579 3972 7579
$$
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, 3:38 PM EDT | Flash Flood Warning | PHI | Chester, Delaware | 4 hr |
| Jul 9, 5:30 PM EDT | Severe Thunderstorm Warning | PHI | Delaware | 45 min |
| Jul 9, 7:52 PM EDT | Severe Thunderstorm Warning | PHI | Sussex | 53 min |
Nearby
Flash Flood Warnings in Pennsylvania, 2026Flash Flood Warnings in Delaware, 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.