Alert archive / Pennsylvania / Flash Flood Warnings in 2024
Flash Flood Warning 57, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 18, 2024, 1:35 AM EDT for 4 counties in Pennsylvania. It was in force for 2 hr. 1 report 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
- Aug 18, 2024, 1:35 AM EDT (05:35 UTC)
- Expired
- Aug 18, 2024, 3:57 AM EDT
- In force
- 2 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 66 km from the middle of the area, began a volume at 05:38 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 |
|---|---|---|---|
| Aug 18, 1:57 AM EDT | FLASH FLOOD | 1 Ssw Summerdale, PA | River gauge on Frankford Creek in Philadelphia rose from 1.71 feet at 142AM to 7.56 feet at 157 AM, cresting near 8.5 feet just after 2 AM. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 00:00Z, 5.6 hours before the alert went out and 218 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
- 735 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 83 m²/s²
- 0-3 km storm-relative helicity
- 106 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
178
WGUS51 KPHI 180535
FFWPHI
PAC017-045-091-101-180945-
/O.NEW.KPHI.FF.W.0057.240818T0535Z-240818T0945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
135 AM EDT Sun Aug 18 2024
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
South Central Bucks County in southeastern Pennsylvania...
East Central Delaware County in southeastern Pennsylvania...
Southeastern Montgomery County in southeastern Pennsylvania...
Philadelphia County in southeastern Pennsylvania...
* Until 545 AM EDT.
* At 135 AM EDT, Doppler radar indicated thunderstorms producing
heavy rain across the warned area. Between 1 and 1.5 inches of
rain have fallen. The expected rainfall rate is 1 to 1.5 inches in
1 hour. Additional rainfall amounts of 0.5 to 1 inch 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...
Philadelphia, Bensalem, Yeadon, Hatboro, Folcroft, Ambler,
Jenkintown, Narberth, East Lansdowne, Rockledge, Abington and Bryn
Athyn.
This includes the following highways...
Interstate 76 in Pennsylvania between mile markers 335 and 350.
Interstate 95 in Pennsylvania between mile markers 10 and 17.
Interstate 676 in Pennsylvania between mile markers 0 and 1.
Pennsylvania Turnpike between mile markers 336 and 353.
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.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 3989 7532 4012 7525 4025 7510 4011 7491
3999 7510 3995 7516 3989 7515 3987 7530
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-1.5 INCHES IN 1 HOUR
$$
RCM2 follow-up statements
138
WGUS71 KPHI 180610
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
210 AM EDT Sun Aug 18 2024
PAC017-045-091-101-180945-
/O.CON.KPHI.FF.W.0057.000000T0000Z-240818T0945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Delaware PA-Montgomery PA-Philadelphia PA-
210 AM EDT Sun Aug 18 2024
...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 AM EDT EARLY THIS
MORNING FOR SOUTH CENTRAL BUCKS, EAST CENTRAL DELAWARE, SOUTHEASTERN
MONTGOMERY AND PHILADELPHIA COUNTIES...
At 210 AM EDT, Doppler radar indicated thunderstorms producing heavy
rain. Frankford Creek has surged out of its banks rapidly and
continues to rise. Between 1 and 1.5 inches of rain have fallen. The
expected rainfall rate is 1 to 1.5 inches in 1 hour. Additional
rainfall amounts of 0.5 to 1 inch are possible in the warned area.
Flash flooding is already occurring.
HAZARD...Flash flooding caused by thunderstorms.
SOURCE...Gauges and 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, Bensalem, Yeadon, Hatboro, Folcroft, Ambler,
Jenkintown, Narberth, East Lansdowne, Rockledge, Abington and Bryn
Athyn.
This includes the following highways...
Interstate 76 in Pennsylvania between mile markers 335 and 350.
Interstate 95 in Pennsylvania between mile markers 10 and 17...and
near mile marker 27.
Interstate 676 in Pennsylvania between mile markers 0 and 1.
Pennsylvania Turnpike between mile markers 336 and 353.
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.
Be aware of your surroundings and do not drive on flooded roads.
&&
LAT...LON 3989 7532 4012 7525 4025 7510 4011 7491
3999 7510 3995 7516 3989 7515 3987 7530
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-1.5 INCHES IN 1 HOUR
$$
RCM539
WGUS71 KPHI 180757
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
357 AM EDT Sun Aug 18 2024
PAC017-045-091-101-180807-
/O.CAN.KPHI.FF.W.0057.000000T0000Z-240818T0945Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-Delaware PA-Montgomery PA-Philadelphia PA-
357 AM EDT Sun Aug 18 2024
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTH CENTRAL BUCKS, EAST
CENTRAL DELAWARE, SOUTHEASTERN MONTGOMERY AND PHILADELPHIA
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 200 AM EDT Monday for portions
of northern Delaware, New Jersey, and Pennsylvania.
&&
LAT...LON 3989 7532 4012 7525 4025 7510 4011 7491
3999 7510 3995 7516 3989 7515 3987 7530
$$
RCMThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 18, 3:09 AM EDT | Flash Flood Warning | PHI | Bucks | 93 min |
| Aug 18, 3:24 PM EDT | Severe Thunderstorm Warning | PHI | Monroe, Northampton | 19 min |
| Aug 18, 3:34 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 41 min |
| Aug 18, 3:48 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Monroe | 42 min |
| Aug 18, 4:04 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 41 min |
| Aug 18, 4:25 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Lehigh, Montgomery, Northampton | 28 min |
| Aug 18, 4:41 PM EDT | Severe Thunderstorm Warning | PHI | Monroe, Northampton | 34 min |
| Aug 18, 4:56 PM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 6 hr |
| Aug 18, 5:21 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 39 min |
| Aug 18, 5:31 PM EDT | Flash Flood Warning | PHI | Bucks, Lehigh, Northampton | 6 hr |
| Aug 18, 5:47 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 58 min |
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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.