Alert archive / Pennsylvania / Flash Flood Warnings in 2021
Flash Flood Warning 67, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 1, 2021, 2:53 PM EDT for 4 counties in Pennsylvania; New Castle County, Delaware. It was in force for 9 hr. 52 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 1, 2021, 2:53 PM EDT (18:53 UTC)
- Expired
- Sep 1, 2021, 11:38 PM EDT
- In force
- 9 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties New Castle County, DE, Berks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 121 km from the middle of the area, began a volume at 18:56 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 1, 3:30 PM EDT | FLASH FLOOD | 1 W East Caln Twp, PA | FLOODING ON US 30 WESTBOUND BETWEEN US 30 BUSINESS AND NORWOOD ROAD. |
| Sep 1, 3:32 PM EDT | FLASH FLOOD | 1 Ese East Caln Twp, PA | SEVERAL ROAD CLOSURES IN DOWNINGTOWN, INCLUDING ON U.S. HIGHWAY 30. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 3:50 PM EDT | FLASH FLOOD | 2 Ese Honey Brook Twp, PA | FLOODING ON US-322 NEAR ROCKVILLE. |
| Sep 1, 4:00 PM EDT | FLASH FLOOD | 1 N Malvern, PA | FLASH FLOODING WITH THE ROAD NEAR IMPASSABLE NEAR THE INTERSECTION OF CHURCH RD AND W SWEDESFORD RD. |
| Sep 1, 4:00 PM EDT | FLASH FLOOD | Pottstown, PA | MULTIPLE WATER RESCUES IN PROGRESS IN POTTSTOWN. |
| Sep 1, 4:20 PM EDT | FLASH FLOOD | 1 Ese South Pottstown, PA | FLOODED ROADWAY AT KEIM STREET. |
| Sep 1, 4:26 PM EDT | FLASH FLOOD | 1 E East Bradford Twp, PA | DOWNINGTOWN PIKE AND HANNUM AVENUE CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 4:30 PM EDT | FLASH FLOOD | Graterford, PA | SMALL CREEK IN THE VICINITY OF PERKIOMEN CREEK NEAR GRATERFORD IS OUT OF ITS BANKS. |
| Sep 1, 4:39 PM EDT | FLASH FLOOD | 2 Ese Honey Brook Twp, PA | U.S. HIGHWAY 322 CLOSED IN THE ROCKVILLE AREA FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 4:54 PM EDT | FLASH FLOOD | 2 Ne West Marlborough T, PA | WATER ENTERING A GARAGE OF A RESIDENCE 4 MILES SSE OF COATESVILLE. |
| Sep 1, 5:15 PM EDT | FLASH FLOOD | 1 Nne Marshallton, PA | THE GAUGE ON EAST BRANCH BRANDYWINE CREEK BELOW DOWNINGTOWN (DWNP1) REACHED FLOOD STAGE AT 515 PM 9/1, CRESTING AT AT 19.11 FEET (RECORD FLOODING) AT 1115 PM 9/1. |
| Sep 1, 5:15 PM EDT | FLASH FLOOD | 1 Ssw Schwenksville, PA | TOWNSHIP LINE ROAD AND MAIN STREET CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:15 PM EDT | FLASH FLOOD | Chesterbrook, PA | THE GAUGE ON VALLEY CREEK AT VALLEY FORGE REACHED FLOOD STAGE AT 515 PM 9/1, CRESTING AT 16.44 FEET (MAJOR FLOOD) AT 630 PM 9/1. |
| Sep 1, 5:16 PM EDT | FLASH FLOOD | Valley Forge, PA | VALLEY FORGE GAUGE AT VALLEY CREEK EXCEEDED FLOOD STAGE. |
| Sep 1, 5:30 PM EDT | FLASH FLOOD | 1 S Devault, PA | MULTIPLE CARS STUCK IN OVER ONE FOOT OF WATER AT THE INTERSECTION OF PA 29 AND GREAT VALLEY PARKWAY. TIME ESTIMATED. |
| Sep 1, 5:30 PM EDT | FLASH FLOOD | 2 Wsw Eastburn Heights, DE | ROUTE 2 BETWEEN RED MILL ROAD AND POSSUM PARK ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:30 PM EDT | FLASH FLOOD | 3 Ese Lower Pottsgrove, PA | NEIFFER ROAD AND GAME FARM ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:34 PM EDT | FLASH FLOOD | 2 W King Of Prussia, PA | GULPH ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:34 PM EDT | FLASH FLOOD | 3 Wnw Uwchlan Twp, PA | ROUTE 100 CLOSED NEAR I-76 FROM FLASH FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:40 PM EDT | FLASH FLOOD | East Whiteland Twp, PA | U.S. HIGHWAY 202 CLOSED NEAR ROUTE 401 FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:45 PM EDT | FLASH FLOOD | Lower Providence Townsh, PA | MANY WATER RESCUES ONGOING AROUND MONTGOMERY COUNTY. |
| Sep 1, 5:49 PM EDT | FLASH FLOOD | 1 Nw Malvern, PA | ROUTE 29 CLOSED BETWEEN U.S. HIGHWAY 30 AND INTERSTATE 76. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 5:57 PM EDT | FLASH FLOOD | Skippack Twp, PA | STATE HIGHWAY 73 CLOSED NEAR ROUTE 113 FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 6:00 PM EDT | FLASH FLOOD | 2 Ene Schwenksville, PA | THE GAUGE ON EAST BRANCH PERKIOMEN CREEK AT SCHWENKSVILLE (SWVP1) REACHED FLOOD STAGE AT 600 PM 9/1, CRESTING AT 16.07 FEET (RECORD FLOODING) AT 1215 AM 9/2. |
| Sep 1, 6:00 PM EDT | FLASH FLOOD | Coatesville, PA | THE GAUGE ON WEST BRANCH BRANDYWINE CREEK AT COATESVILLE (COTP1) REACHED FLOOD STAGE AT 600 PM 9/1, CRESTING AT 9.62 FEET (MODERATE FLOODING) AT 700 PM 9/1. |
| Sep 1, 6:00 PM EDT | FLASH FLOOD | Modena, PA | THE GAUGE ON WEST BRANCH BRANDYWINE CREEK AT MODERNA (MODP1) REACHED FLOOD STAGE AT 600 PM 9/1, CRESTING AT 13.38 FEET (RECORD FLOODING) AT 800 PM 9/1. |
| Sep 1, 6:07 PM EDT | FLASH FLOOD | 1 Ssw King Of Prussia, PA | CLOSURES ON INTERSTATE 76 FROM FLOODING. TIME BASED ON DISPATCH REPORTS. |
| Sep 1, 6:09 PM EDT | FLASH FLOOD | 2 Ne Brookside, DE | OGLETOWN ROAD AND OLD OGLETOWN ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 6:15 PM EDT | FLASH FLOOD | 2 Wsw Newtown Twp, PA | THE GAUGE ON CRUM CREEK AT NEWTOWN SQUARE (NTSP1) REACHED FLOOD STAGE AT 615 PM 9/1, CRESTING AT 12.25 FEET (MAJOR FLOODING) AT 815 PM 9/1. |
| Sep 1, 6:15 PM EDT | FLASH FLOOD | Graterford, PA | THE GAUGE AT PERKIOMEN CREEK AT GRATERFORD (GRAP1) REACHED FLOOD STAGE AT 615 PM. |
| Sep 1, 6:25 PM EDT | FLASH FLOOD | 1 Nne Graterford, PA | FLOODING CLOSED SKIPPACK PIKE NEAR CROSS ROAD. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 6:30 PM EDT | FLASH FLOOD | 2 S Brookside, DE | THE GAUGE ON CHRISTINA RIVER AT COOCHS BRIDGE (CHBD1) REACHED FLOOD STAGE AT 630 PM 9/1, CRESTING AT 12.85 FEET (MODERATE FLOODING) AT 1000 PM 9/1. |
| Sep 1, 6:32 PM EDT | FLASH FLOOD | Collegeville, PA | FLOODING CLOSED STATE ROUTE 29 NEAR THE MAIN STREET INTERSECTION. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 6:32 PM EDT | FLASH FLOOD | South Pottstown, PA | FLASH FLOODING CLOSED PORTIONS OF U.S. HIGHWAY 422 NEAR STATE ROUTE 100 IN SOUTH POTTSTOWN. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 6:38 PM EDT | FLASH FLOOD | Bridgeport, PA | FLOODING ON STATE ROUTE 23 IN THE BRIDGEPORT AND SWEDESBURG AREAS. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 6:45 PM EDT | FLASH FLOOD | Bridgeport, PA | THE GAUGE ON THE SCHUYLKILL RIVER AT NORRISTOWN (NRSP1) REACHED FLOOD STAGE AT 645 PM 9/1, CRESTING AT 26.85 FEET (RECORD FLOODING) AT 615 AM 9/2. |
| Sep 1, 6:55 PM EDT | FLASH FLOOD | Coatesville, PA | STATE HIGHWAY 82 CLOSED IN SEVERAL LOCATIONS IN COATESVILLE. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 7:09 PM EDT | FLASH FLOOD | 2 Nne West Vincent Twp, PA | FLOODING CLOSED PUGHTOWN ROAD, COLD STREAM ROAD, AND DAISY POINT ROAD. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 7:14 PM EDT | HEAVY RAIN 5.13 | 1 Ese East Vincent Twp, PA | |
| Sep 1, 7:30 PM EDT | FLASH FLOOD | 1 Sse Eastburn Heights, DE | THE GAUGE ON WHITE CLAY CREEK NEAR NEWARK (DPKD1) REACHED FLOOD STAGE AT 730 PM 9/1, CRESTING AT 15.77 FEET (MODERATE FLOODING) AT 715 AM 9/2. |
| Sep 1, 7:30 PM EDT | FLASH FLOOD | Wooddale, DE | THE GAUGE ON RED CLAY CREEK AT WOODDALE (RCCD1) REACHED FLOOD STAGE AT 730 PM 9/1, CRESTING AT 9.2 FEET (MODERATE FLOODING) AT 345 AM 9/2. |
| Sep 1, 7:37 PM EDT | FLASH FLOOD | 1 Nw Landenberg, PA | FLOODING CLOSED CLAY CREEK ROAD AND BANK ROAD. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 8:03 PM EDT | FLASH FLOOD | 1 Nw Cedarville, PA | FLOODING CLOSED ROUTE 724 WEST OF POTTSTOWN LANDING. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 8:15 PM EDT | FLASH FLOOD | 2 Se Honey Brook Twp, PA | THE GAUGE ON THE WEST BRANCH BRANDYWINE CREEK AT HONEY BROOK (HNBP1) REACHED FLOOD STAGE AT 815 PM 9/1, CRESTING AT 9.61 FEET (MODERATE FLOODING) AT 1030 PM 9/1. |
| Sep 1, 8:30 PM EDT | FLASH FLOOD | South Pottstown, PA | THE GAUGE ON THE SCHUYLKILL RIVER AT POTTSTOWN (PTNP1) REACHED FLOOD STAGE AT 830 PM 9/1, CRESTING AT 16.79 FEET (MODERATE FLOODING) AT 445 PM 9/2. |
| Sep 1, 9:00 PM EDT | FLASH FLOOD | Chadds Ford Twp, PA | THE GAUGE ON BRANDYWINE CREEK AT CHADDS FORD (CDFP1) REACHED FLOOD STAGE AT 900 PM 9/1, CRESTING AT 21.04 FEET (RECORD FLOODING) AT 500 AM 9/2. |
| Sep 1, 9:00 PM EDT | FLASH FLOOD | Skippack Twp, PA | *** 1 FATAL *** FLASH FLOODING SWEPT AWAY A CAR AND KILLED AN OCCUPANT IN SKIPPACK TWP. |
| Sep 1, 9:45 PM EDT | FLASH FLOOD | 1 Ne Edgmont Twp, PA | FLOODING ON GRADYVILLE ROAD FORCED ITS CLOSURE. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 9:45 PM EDT | FLASH FLOOD | 2 E London Britain Twp, PA | THE GAUGE ON WHITE CLAY CREEK AT STRICKLERSVILLE (SKVP1) REACHED FLOOD STAGE AT 945 PM 9/1, CRESTING AT 12.68 FEET (MAJOR FLOODING) AT 130 AM 9/2. |
| Sep 1, 10:00 PM EDT | FLASH FLOOD | Bridgeport, PA | *** 1 FATAL *** A MAN WAS FOUND DEAD IN HIS RESIDENCE IN BRIDGEPORT FROM FLASH FLOODING. |
| Sep 1, 10:01 PM EDT | FLASH FLOOD | 1 Ne Skippack, PA | FLASH FLOODING OF WEST BRANCH SKIPPACK CREEK FORCED THE CLOSURE OF OLD FORTY FOOT ROAD. TIME BASED ON DISPATCH REPORT. |
| Sep 1, 10:16 PM EDT | FLASH FLOOD | Cheyney, PA | FLASH FLOODING OF CHESTER CREEK FORCED THE CLOSURE OF CHEYNEY ROAD. TIME BASED ON DISPATCH 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, 6.9 hours before the alert went out and 174 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
- 558 J/kg
- Mixed-layer CIN
- -21 J/kg
- Mixed-layer LCL
- 575 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 122 m²/s²
- 0-3 km storm-relative helicity
- 223 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 2.6
The text
As transmitted.
012
WGUS51 KPHI 011853
FFWPHI
DEC003-PAC011-029-045-091-012300-
/O.NEW.KPHI.FF.W.0067.210901T1853Z-210901T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
253 PM EDT Wed Sep 1 2021
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Northwestern New Castle County in northern Delaware...
Southeastern Berks County in eastern Pennsylvania...
Chester County in southeastern Pennsylvania...
Western Delaware County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
* Until 700 PM EDT.
* At 253 PM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 0.5 and 1 inch of rain
has fallen. Flash flooding is ongoing or expected to begin
shortly. Additional rainfall is expected over the next couple
hours.
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...
Wilmington, Newark, West Chester, Norristown, Pottstown,
Phoenixville, Lansdale, West Norriton, East Norriton, Coatesville,
Westtown, and Downingtown.
This includes the following highways...
Pennsylvania Turnpike between mile markers 298 and 331.
Interstate 95 in Delaware between mile markers 0 and 19.
Interstate 76 in Pennsylvania between mile markers 327 and 330.
Northeast Extension between mile markers 23 and 30.
This includes the following streams and drainages...
Chester-Sassafras, Crosswicks-Neshaminy, Brandywine-Christina,
Schuylkill, Lower Delaware, and Lower Susquehanna.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 3972 7610 3983 7604 3983 7602 3985 7602
3987 7599 3993 7598 3995 7599 4004 7593
4011 7594 4014 7587 4016 7590 4020 7583
4027 7575 4027 7541 4022 7524 3991 7545
3972 7551 3962 7573 3963 7579 3972 7579
FLASH FLOOD...RADAR INDICATED
$$
NC3 follow-up statements
695
WGUS51 KPHI 012147
FFWPHI
DEC003-PAC011-029-045-091-020100-
/O.EXT.KPHI.FF.W.0067.000000T0000Z-210902T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
547 PM EDT Wed Sep 1 2021
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Northwestern New Castle County in northern Delaware...
Southeastern Berks County in eastern Pennsylvania...
Chester County in southeastern Pennsylvania...
Western Delaware County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
* Until 900 PM EDT.
* At 547 PM EDT, emergency management reported thunderstorms
producing heavy rain in Chester County. Between 2 and 4 inches of
rain have fallen. 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...
Wilmington, Newark, West Chester, Norristown, Pottstown,
Phoenixville, Lansdale, West Norriton, East Norriton, Coatesville,
Westtown, and Downingtown.
This includes the following highways...
Pennsylvania Turnpike between mile markers 298 and 331.
Interstate 95 in Delaware between mile markers 0 and 19.
Interstate 76 in Pennsylvania between mile markers 327 and 330.
Northeast Extension between mile markers 23 and 30.
This includes the following streams and drainages...
Chester-Sassafras, Crosswicks-Neshaminy, Brandywine-Christina,
Schuylkill, Lower Delaware, and Lower Susquehanna.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 3972 7610 3983 7604 3983 7602 3985 7602
3987 7599 3993 7598 3995 7599 4004 7593
4011 7594 4014 7587 4016 7590 4020 7583
4027 7575 4027 7541 4022 7524 3991 7545
3972 7551 3962 7573 3963 7579 3972 7579
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
NC703
WGUS51 KPHI 012353
FFWPHI
DEC003-PAC011-029-045-091-020400-
/O.EXT.KPHI.FF.W.0067.000000T0000Z-210902T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
753 PM EDT Wed Sep 1 2021
The National Weather Service in Mount Holly has extended the
* Flash Flood Warning for...
Northwestern New Castle County in northern Delaware...
Southeastern Berks County in eastern Pennsylvania...
Chester County in southeastern Pennsylvania...
Western Delaware County in southeastern Pennsylvania...
Central Montgomery County in southeastern Pennsylvania...
* Until midnight EDT.
* At 753 PM EDT, local law enforcement reported flash flooding in
much of Chester County. Several water rescues are ongoing. In
addition, several river and stream gauges are in flood. Widespread
flooding is expected to continue for the next several hours. Avoid
travel in this area. Between 3 and 6 inches of rain have fallen.
Flash flooding is already occurring.
HAZARD...Life threatening flash flooding caused by heavy rain.
SOURCE...Law enforcement reported.
IMPACT...Life threatening flash flooding of creeks and streams,
urban areas, highways, streets, and underpasses.
* Some locations that may experience flash flooding include...
Wilmington, Newark, West Chester, Norristown, Pottstown,
Phoenixville, Lansdale, West Norriton, East Norriton, Coatesville,
Westtown, and Downingtown.
This includes the following highways...
Pennsylvania Turnpike between mile markers 298 and 331.
Interstate 95 in Delaware between mile markers 0 and 19.
Interstate 76 in Pennsylvania between mile markers 327 and 330.
Northeast Extension between mile markers 23 and 30.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 3972 7610 3983 7604 3983 7602 3985 7602
3987 7599 3993 7598 3995 7599 4004 7593
4011 7594 4014 7587 4016 7590 4020 7583
4027 7575 4027 7541 4022 7524 3991 7545
3972 7551 3962 7573 3963 7579 3972 7579
FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
$$
CMS119
WGUS71 KPHI 020338
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
1138 PM EDT Wed Sep 1 2021
DEC003-PAC011-029-045-091-020348-
/O.CAN.KPHI.FF.W.0067.000000T0000Z-210902T0400Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Berks PA-Chester PA-Delaware PA-Montgomery PA-
1138 PM EDT Wed Sep 1 2021
...FLASH FLOOD WARNING FOR NORTHWESTERN NEW CASTLE, SOUTHEASTERN
BERKS, CHESTER, WESTERN DELAWARE, AND CENTRAL MONTGOMERY COUNTIES
HAS BEEN REPLACED WITH A FLOOD WARNING...
Refer to the flood warning bulletin for more information. Please
continue to heed road closures.
LAT...LON 3972 7610 3983 7604 3983 7602 3985 7602
3987 7599 3993 7598 3995 7599 4004 7593
4011 7594 4014 7587 4016 7590 4020 7583
4027 7575 4027 7541 4022 7524 3991 7545
3972 7551 3962 7573 3963 7579 3972 7579
$$
CMSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 1, 6:19 AM EDT | Areal Flood Advisory | PHI | Chester, Delaware | 116 min |
| Sep 1, 6:49 AM EDT | Flash Flood Warning | PHI | Chester, Delaware, Philadelphia | 86 min |
| Sep 1, 11:24 AM EDT | Areal Flood Advisory | PHI | Berks, Carbon, Lehigh, Monroe, Northampton | 3 hr |
| Sep 1, 12:07 PM EDT | Flash Flood Warning | PHI | Carbon, Monroe | 4 hr |
| Sep 1, 1:29 PM EDT | Flash Flood Warning | PHI | Berks, Lehigh | 6 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Montgomery | 36 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Chester, Montgomery, Philadelphia | 43 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Montgomery, Philadelphia | 41 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Philadelphia | 39 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Berks | 24 hr |
| Sep 1, 4:02 PM EDT | River Flood Warning | PHI | Monroe | 24 hr |
| Sep 1, 4:04 PM EDT | Areal Flood Warning | PHI | Carbon, Monroe, Northampton | 24 hr |
| Sep 1, 4:10 PM EDT | River Flood Warning | PHI | Monroe | 19 hr |
| Sep 1, 4:12 PM EDT | Flash Flood Warning | PHI | Berks, Bucks, Lehigh, Montgomery, Northampton | 7 hr |
| Sep 1, 4:12 PM EDT | River Flood Warning | PHI | Lehigh, Northampton | 25 hr |
| Sep 1, 4:12 PM EDT | River Flood Warning | PHI | Lehigh, Northampton | 24 hr |
| Sep 1, 4:12 PM EDT | River Flood Warning | PHI | Carbon | 15 hr |
| Sep 1, 4:13 PM EDT | Tornado Warning | PHI | Chester | 32 min |
| Sep 1, 4:20 PM EDT | River Flood Warning | PHI | Montgomery | 22 hr |
| Sep 1, 4:21 PM EDT | River Flood Warning | PHI | Bucks | 29 hr |
| Sep 1, 4:42 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery | 6 hr |
| Sep 1, 5:07 PM EDT | River Flood Warning | PHI | Chester | 17 hr |
| Sep 1, 5:13 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 47 min |
| Sep 1, 5:15 PM EDT | Tornado Warning | PHI | Delaware, Montgomery, Philadelphia | 30 min |
| Sep 1, 5:26 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 9 hr |
| Sep 1, 5:34 PM EDT | Tornado Warning | PHI | Bucks, Montgomery, Philadelphia | 26 min |
| Sep 1, 5:42 PM EDT | Flash Flood Warning | PHI | Bucks | 10 hr |
| Sep 1, 5:57 PM EDT | Tornado Warning | PHI | Bucks | 33 min |
| Sep 1, 6:08 PM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 6 hr |
| Sep 1, 6:20 PM EDT | Tornado Warning | PHI | Bucks | 40 min |
| Sep 1, 6:22 PM EDT | Tornado Warning | PHI | Philadelphia | 23 min |
| Sep 1, 6:38 PM EDT | River Flood Warning | PHI | Chester, Delaware | 26 hr |
| Sep 1, 6:42 PM EDT | Tornado Warning | PHI | Bucks, Philadelphia | 33 min |
| Sep 1, 6:59 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 61 min |
| Sep 1, 7:04 PM EDT | Tornado Warning | PHI | Bucks | 26 min |
| Sep 1, 7:05 PM EDT | Flash Flood Warning | PHI | Bucks | 8 hr |
| Sep 1, 7:22 PM EDT | Tornado Warning | PHI | Bucks | 11 min |
| Sep 1, 7:23 PM EDT | Areal Flood Warning | PHI | Berks, Lehigh | 14 hr |
| Sep 1, 7:31 PM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Sep 1, 7:53 PM EDT | River Flood Warning | PHI | Delaware | 13 hr |
| Sep 1, 8:03 AM EDT | River Flood Warning | PHI | New Castle | 4 hr |
| Sep 1, 4:59 PM EDT | Tornado Warning | PHI | Kent, Sussex | 46 min |
| Sep 1, 5:01 PM EDT | Tornado Warning | PHI | Kent, New Castle | 44 min |
| Sep 1, 5:16 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 44 min |
| Sep 1, 5:35 PM EDT | Tornado Warning | PHI | Kent, New Castle | 25 min |
| Sep 1, 6:03 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 42 min |
| Sep 1, 6:08 PM EDT | River Flood Warning | PHI | New Castle | 18 hr |
| Sep 1, 6:15 PM EDT | River Flood Warning | PHI | New Castle | 9 hr |
| Sep 1, 6:24 PM EDT | Tornado Warning | PHI | New Castle | 16 min |
| Sep 1, 6:38 PM EDT | River Flood Warning | PHI | New Castle | 28 hr |
| Sep 1, 6:57 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 63 min |
| Sep 1, 7:44 PM EDT | River Flood Warning | PHI | New Castle | 11 hr |
Nearby
Flash Flood Warnings in Pennsylvania, 2021Flash Flood Warnings in Delaware, 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.