Alert archive / Pennsylvania / Flash Flood Warnings in 2024
Flash Flood Warning 31, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 6, 2024, 4:32 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 8 hr. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Aug 6, 2024, 4:32 PM EDT (20:32 UTC)
- Expired
- Aug 7, 2024, 12:03 AM EDT
- In force
- 8 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Chester County, PA, Delaware County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 114 km from the middle of the area, began a volume at 20:35 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.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 8.5 hours before the alert went out and 185 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
- 527 J/kg
- Mixed-layer CIN
- -107 J/kg
- Mixed-layer LCL
- 1272 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 19 m²/s²
- 0-3 km storm-relative helicity
- 93 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.2
The text
As transmitted.
024
WGUS51 KPHI 062032
FFWPHI
PAC029-045-091-070030-
/O.NEW.KPHI.FF.W.0031.240806T2032Z-240807T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
432 PM EDT Tue Aug 6 2024
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Chester County in southeastern Pennsylvania...
North Central Delaware County in southeastern Pennsylvania...
Southwestern Montgomery County in southeastern Pennsylvania...
* Until 830 PM EDT.
* At 432 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen over the last hour with training storms likely.
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.
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, Phoenixville, West Norriton, East Norriton,
Coatesville, Westtown, Downingtown, Collegeville, Royersford,
Parkesburg, Trappe and Honey Brook.
This includes the following highways...
Interstate 476 in Pennsylvania near mile marker 13.
Interstate 76 in Pennsylvania between mile markers 327 and 329.
Pennsylvania Turnpike between mile markers 301 and 328.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4003 7535 4001 7541 3999 7543 3993 7555
3986 7601 3987 7600 3987 7599 3993 7600
3993 7598 3996 7599 4004 7593 4011 7594
4014 7588 4016 7584 4019 7561 4020 7538
FLASH FLOOD...RADAR INDICATED
$$
Deal3 follow-up statements
450
WGUS51 KPHI 062358
FFWPHI
PAC029-045-091-070230-
/O.EXT.KPHI.FF.W.0031.000000T0000Z-240807T0230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
758 PM EDT Tue Aug 6 2024
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Chester County in southeastern Pennsylvania...
North Central Delaware County in southeastern Pennsylvania...
Southwestern Montgomery County in southeastern Pennsylvania...
* Until 1030 PM EDT.
* At 758 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms produced heavy rain across the warned area. Between
1 and 2 inches of rain have fallen. Another round of strong
thunderstorms with rainfall rates of 1 to 2 inches per hour are
expected. 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, Phoenixville, West Norriton, East Norriton,
Coatesville, Westtown, Downingtown, Collegeville, Royersford,
Parkesburg, Trappe and Honey Brook.
This includes the following highways...
Interstate 476 in Pennsylvania near mile marker 13.
Interstate 76 in Pennsylvania between mile markers 327 and 329.
Pennsylvania Turnpike between mile markers 301 and 328.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4003 7535 4001 7541 3999 7543 3993 7555
3986 7601 3987 7600 3987 7599 3993 7600
3993 7598 3996 7599 4004 7593 4011 7594
4014 7588 4016 7584 4019 7561 4020 7538
FLASH FLOOD...RADAR AND GAUGE INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
MJL847
WGUS51 KPHI 070215
FFWPHI
PAC029-045-091-070430-
/O.EXT.KPHI.FF.W.0031.000000T0000Z-240807T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1015 PM EDT Tue Aug 6 2024
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Northeastern Chester County in southeastern Pennsylvania...
North Central Delaware County in southeastern Pennsylvania...
Southwestern Montgomery County in southeastern Pennsylvania...
* Until 1230 AM EDT.
* At 1015 PM EDT, Doppler radar and automated rain gauges indicated
thunderstorms producing heavy rain across the warned area. Between
1 and 2 inches of rain have fallen. 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 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, Phoenixville, West Norriton, East Norriton,
Westtown, Downingtown, Collegeville, Royersford, Trappe, Paoli,
Valley Forge and Chester Springs.
This includes the following highways...
Interstate 476 in Pennsylvania near mile marker 13.
Interstate 76 in Pennsylvania between mile markers 327 and 329.
Pennsylvania Turnpike between mile markers 311 and 328.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4003 7535 4001 7541 3999 7543 3993 7555
3996 7564 3999 7569 4006 7570 4013 7567
4019 7561 4020 7538
FLASH FLOOD...RADAR AND GAUGE INDICATED
$$
MJL175
WGUS71 KPHI 070403 RRD
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
1203 AM EDT Wed Aug 7 2024
PAC029-045-091-070413-
/O.CAN.KPHI.FF.W.0031.000000T0000Z-240807T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-Montgomery PA-
1203 AM EDT Wed Aug 7 2024
...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN CHESTER, NORTH
CENTRAL DELAWARE AND SOUTHWESTERN MONTGOMERY COUNTIES...
The heavy rain has ended. While the flash flood threat has ended,
flooding remains an issue and a new flood warning will be issued.
Please continue to heed remaining road closures.
A Flood Watch remains in effect until 1200 PM EDT Wednesday for
portions of northern Delaware, New Jersey, and Pennsylvania.
&&
LAT...LON 4003 7535 4001 7541 3999 7543 3993 7555
3996 7564 3999 7569 4006 7570 4013 7567
4019 7561 4020 7538
$$
MPSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 6, 9:37 AM EDT | Heat Advisory | PHI | Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more | 9 hr |
| Aug 6, 3:23 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 37 min |
| Aug 6, 4:00 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 47 min |
| Aug 6, 4:37 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 40 min |
| Aug 6, 6:37 PM EDT | Flash Flood Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 3 hr |
| Aug 6, 6:57 PM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 3 hr |
| Aug 6, 7:09 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Montgomery | 48 min |
| Aug 6, 7:32 PM EDT | Flash Flood Warning | PHI | Berks | 3 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2024Every flash flood warning in 2024
Sources
The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.