Alert archive / Pennsylvania / Flash Flood Warnings in 2021
Flash Flood Warning 85, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 23, 2021, 12:28 PM EDT for 4 counties in Pennsylvania. It was in force for 4 hr. 23 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
- Sep 23, 2021, 12:28 PM EDT (16:28 UTC)
- Expired
- Sep 23, 2021, 4:30 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, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 16:28 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 |
|---|---|---|---|
| Sep 23, 12:30 PM EDT | FLASH FLOOD | Caln Twp, PA | MULTIPLE OCCUPANTS OF A VEHICLE RESCUED FROM FLOOD WATERS. TIME ESTIMATED FROM NEARBY REPORTS. |
| Sep 23, 12:36 PM EDT | FLASH FLOOD | 1 N Coatesville, PA | WATER RESCUE NEAR THE INTERSECTION OF MANOR ROAD AND BUTTERWORTH ROAD. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 12:51 PM EDT | FLASH FLOOD | Eddystone, PA | WATER RESCUE NEAR THE INTERSECTION OF INDUSTRIAL HIGHWAY AND SAVILLE AVENUE. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:00 PM EDT | FLASH FLOOD | 1 S Eddystone, PA | WATER RESCUE NEAR THE INTERSECTION OF EDDYSTONE AVENUE AND 4TH STREET. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:04 PM EDT | FLOOD | 2 W West Conshohocken, PA | FLOODING ON INTERSTATE 76 NEAR GULPH MILLS WITH LANE RESTRICTIONS. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:18 PM EDT | FLOOD | 1 Nne Lawrence Park, PA | FLOODING ON INTERSTATE 476 IN BROOMALL WITH LANE RESTRICTIONS. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:30 PM EDT | FLASH FLOOD | 1 S Penn Wynne, PA | THE GAUGE ON COBBS CREEK IN PHILADELPHIA REACHED MINOR FLOOD STAGE. |
| Sep 23, 1:37 PM EDT | FLASH FLOOD | 2 Ese Conshohocken, PA | RIVER ROAD AND HARTS LANE CLOSED FROM FLASH FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:40 PM EDT | FLASH FLOOD | 1 Ene Darby Twp, PA | WATER RESCUE NEAR THE INTERSECTION OF BARTRAM AVENUE AND OAK LANE. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:43 PM EDT | FLASH FLOOD | Morton, PA | WATER RESCUE NEAR THE INTERSECTION OF WAVERLY TERRACE AND UNITY TERRACE. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:45 PM EDT | FLASH FLOOD | 1 S Upper Darby, PA | WATER RESCUE NEAR THE INTERSECTION OF MARSHALL ROAD AND ASHTON ROAD. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 1:54 PM EDT | FLASH FLOOD | Nether Providence Twp, PA | ROGERS LANE CLOSED FROM FLASH FLOODING. TIME ESTIMATED FROM RADAR. |
| Sep 23, 2:00 PM EDT | FLASH FLOOD | 1 Ssw East Vincent Twp, PA | THE GAUGE ON FRENCH CREEK NEAR PHOENIXVILLE REACHED FLOOD STAGE. |
| Sep 23, 2:00 PM EDT | HEAVY RAIN 1.61 | Media, PA | STREET FLOODING IN MEDIA. |
| Sep 23, 2:08 PM EDT | HEAVY RAIN 3.13 | 2 S East Nantmeal Twp, PA | |
| Sep 23, 2:10 PM EDT | FLASH FLOOD | 1 Wnw West Conshohocken, PA | SWEDELAND ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 2:11 PM EDT | FLOOD | 2 Ene Yeadon, PA | SOCIAL MEDIA REPORT OF STREET FLOODING ON 51ST STREET AND BALTIMORE AVENUE. |
| Sep 23, 2:20 PM EDT | FLOOD | Chester Springs, PA | FLOODING OF PINE CREEK; WATER STILL RISING. |
| Sep 23, 2:20 PM EDT | FLASH FLOOD | 2 Ese South Philadelphi, PA | BROAD STREET EXIT OFF INTERSTATE 95 IS FLOODED AND IMPASSABLE. TIME BASED ON SOCIAL MEDIA REPORT. |
| Sep 23, 2:30 PM EDT | FLASH FLOOD | Eastwick, PA | SEVERAL REPORTS OF FLOODING ON INTERSTATE 95 NEAR PHILADELPHIA INTERNATIONAL AIRPORT. RAMP CLOSURES AND LANE RESTRICTIONS REQUIRED. TIME BASED ON DISPATCH REPORTS. |
| Sep 23, 2:52 PM EDT | HEAVY RAIN 2.32 | East Nantmeal Twp, PA | |
| Sep 23, 3:29 PM EDT | FLASH FLOOD | 1 Sse Ridley Park, PA | WATER RESCUE NEAR THE INTERSECTION OF INDUSTRIAL HIGHWAY AND STEWART AVENUE. TIME BASED ON DISPATCH REPORT. |
| Sep 23, 3:35 PM EDT | FLASH FLOOD | 1 W Drexel Hill, PA | BURMONT ROAD FLOODED WITH ROAD CLOSURES. TIME BASED ON SOCIAL MEDIA REPORT. |
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, 4.5 hours before the alert went out and 203 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
- 517 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- -71 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.0
The text
As transmitted.
047
WGUS51 KPHI 231628
FFWPHI
PAC029-045-091-101-232030-
/O.NEW.KPHI.FF.W.0085.210923T1628Z-210923T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1228 PM EDT Thu Sep 23 2021
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Northeastern Chester County in southeastern Pennsylvania...
Eastern Delaware County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
Western Philadelphia County in southeastern Pennsylvania...
* Until 430 PM EDT.
* At 1228 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 2 inches of rain
have fallen. The expected rainfall rate is 1 to 2 inches in 1
hour. 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...
Philadelphia, Norristown, Chester, Pottstown, Phoenixville, West
Norriton, East Norriton, Coatesville, Yeadon, Downingtown,
Conshohocken, and Folcroft.
This includes the following highways...
Pennsylvania Turnpike between mile markers 301 and 336.
Interstate 95 in Pennsylvania between mile markers 7 and 15.
Interstate 76 in Pennsylvania between mile markers 327 and 349.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
Northeast Extension between mile markers 21 and 30.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 3994 7582 4014 7587 4020 7577 4031 7553
4025 7533 4016 7524 3992 7515 3986 7522
3984 7535 3986 7535 4000 7553
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
NC2 follow-up statements
753
WGUS71 KPHI 231751
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
151 PM EDT Thu Sep 23 2021
PAC029-045-091-101-232030-
/O.CON.KPHI.FF.W.0085.000000T0000Z-210923T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-Montgomery PA-Philadelphia PA-
151 PM EDT Thu Sep 23 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM EDT THIS
AFTERNOON FOR NORTHEASTERN CHESTER, EASTERN DELAWARE, CENTRAL
MONTGOMERY, AND WESTERN PHILADELPHIA COUNTIES...
At 151 PM EDT, Doppler radar indicated thunderstorms producing heavy
rain in Downingtown and portions of Chester County. Between 1.5 and
3 inches of rain have fallen. The expected rainfall rate is 1 to 2
inches in 1 hour. Flash flooding is already occurring in portions of
the warning area with various roads closed and water rescues
reported.
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...
Philadelphia, Norristown, Chester, Pottstown, Phoenixville, West
Norriton, East Norriton, Coatesville, Yeadon, Downingtown,
Conshohocken, and Folcroft.
This includes the following highways...
Pennsylvania Turnpike between mile markers 301 and 336.
Interstate 95 in Pennsylvania between mile markers 7 and 16.
Interstate 76 in Pennsylvania between mile markers 327 and 350.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
Northeast Extension between mile markers 21 and 30.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 3994 7582 4014 7587 4020 7577 4031 7553
4025 7533 4016 7524 3992 7515 3986 7522
3984 7535 3986 7535 4000 7553
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
NC445
WGUS71 KPHI 231830
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
230 PM EDT Thu Sep 23 2021
PAC029-045-091-101-232030-
/O.CON.KPHI.FF.W.0085.000000T0000Z-210923T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Chester PA-Delaware PA-Montgomery PA-Philadelphia PA-
230 PM EDT Thu Sep 23 2021
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM EDT THIS
AFTERNOON FOR NORTHEASTERN CHESTER, EASTERN DELAWARE, CENTRAL
MONTGOMERY, AND WESTERN PHILADELPHIA COUNTIES...
At 230 PM EDT, Doppler radar indicated thunderstorms producing heavy
rain in Delaware county. Between 1.5 and 3 inches of rain have
fallen. Flash flooding is already occurring in much of Delaware
county, with several water rescues reported.
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...
Philadelphia, Norristown, Chester, Phoenixville, West Norriton,
East Norriton, Yeadon, Conshohocken, Folcroft, Swarthmore,
Collegeville, and Royersford.
This includes the following highways...
Pennsylvania Turnpike between mile markers 317 and 336.
Interstate 95 in Pennsylvania between mile markers 7 and 16.
Interstate 76 in Pennsylvania between mile markers 327 and 350.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
Northeast Extension between mile markers 21 and 30.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4031 7553 4025 7533 4016 7524 3992 7515
3986 7522 3984 7535 3986 7535 4018 7571
4019 7565
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL...1-2 INCHES IN 1 HOUR
$$
NCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 23, 9:12 AM EDT | Coastal Flood Advisory | PHI | Bucks, Delaware, Philadelphia | 10 hr |
| Sep 23, 10:52 AM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Sep 23, 11:33 AM EDT | Areal Flood Advisory | PHI | Berks, Chester, Delaware, Montgomery, Philadelphia | 3 hr |
| Sep 23, 11:40 AM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Carbon, Lehigh, Montgomery, Northampton | 3 hr |
| Sep 23, 11:57 AM EDT | Flash Flood Warning | PHI | Chester, Delaware | 3 hr |
| Sep 23, 12:12 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 48 min |
| Sep 23, 12:54 PM EDT | Special Weather Statement | PHI | Philadelphia | 51 min |
| Sep 23, 12:56 PM EDT | Areal Flood Advisory | PHI | Bucks, Carbon, Lehigh, Monroe, Montgomery, Northampton and 1 more | 3 hr |
| Sep 23, 12:57 PM EDT | Special Weather Statement | PHI | Bucks | 33 min |
| Sep 23, 1:13 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 47 min |
| Sep 23, 1:42 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Sep 23, 1:48 PM EDT | River Flood Warning | PHI | Chester | 5 hr |
| Sep 23, 1:58 PM EDT | Special Weather Statement | PHI | Bucks | 32 min |
| Sep 23, 2:37 PM EDT | Areal Flood Advisory | PHI | Bucks, Northampton | 3 hr |
| Sep 23, 3:26 PM EDT | Flash Flood Warning | PHI | Bucks | 2 hr |
| Sep 23, 4:26 PM EDT | Areal Flood Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 80 min |
| Sep 23, 7:18 PM EDT | Areal Flood Warning | PHI | Berks, Montgomery | 36 min |
Nearby
Flash Flood Warnings in Pennsylvania, 2021Every flash flood warning in 2021
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.