Alert archive / Pennsylvania / Flash Flood Warnings in 2024
Flash Flood Warning 52, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 9, 2024, 2:50 PM EDT for Lehigh County, Northampton County, Pennsylvania. It was in force for 2 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 9, 2024, 2:50 PM EDT (18:50 UTC)
- Expired
- Aug 9, 2024, 5:05 PM EDT
- In force
- 2 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Lehigh County, PA, Northampton County, PA
The radar
The Philadelphia radar (KDIX), 107 km from the middle of the area, began a volume at 18:53 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
Brookhaven, NY (KOKX), launched 12:00Z, 6.8 hours before the alert went out and 217 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
- 988 J/kg
- Mixed-layer CIN
- -3 J/kg
- Mixed-layer LCL
- 536 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 223 m²/s²
- 0-3 km storm-relative helicity
- 245 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 13.0
The text
As transmitted.
091
WGUS51 KPHI 091850
FFWPHI
PAC077-095-092245-
/O.NEW.KPHI.FF.W.0052.240809T1850Z-240809T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
250 PM EDT Fri Aug 9 2024
The National Weather Service in Mount Holly has issued a
* Flash Flood Warning for...
Southeastern Lehigh County in eastern Pennsylvania...
South Central Northampton County in eastern Pennsylvania...
* Until 645 PM EDT.
* At 250 PM EDT, Doppler radar indicated heavy rain across the
warned area. 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 heavy rain.
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...
Allentown, Bethlehem, Emmaus, Hellertown, Lehigh University,
Zionsville, Fountain Hill, Macungie, Freemansburg and Coopersburg.
This includes the following highways...
Northeast Extension between mile markers 46 and 53.
Interstate 78 in Pennsylvania between mile markers 57 and 70.
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.
&&
LAT...LON 4060 7527 4054 7534 4050 7540 4049 7540
4042 7549 4049 7560 4061 7547 4069 7536
FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR
$$
MJL1 follow-up statement
283
WGUS71 KPHI 092105
FFSPHI
Flash Flood Statement
National Weather Service Mount Holly NJ
505 PM EDT Fri Aug 9 2024
PAC077-095-092115-
/O.CAN.KPHI.FF.W.0052.000000T0000Z-240809T2245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lehigh PA-Northampton PA-
505 PM EDT Fri Aug 9 2024
...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN LEHIGH AND
SOUTH CENTRAL NORTHAMPTON COUNTIES...
The heavy rain has ended. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
A Flood Watch remains in effect until 100 AM EDT Saturday for
portions of northern Delaware, New Jersey, and Pennsylvania.
&&
LAT...LON 4060 7527 4054 7534 4050 7540 4049 7540
4042 7549 4049 7560 4061 7547 4069 7536
$$
MJLThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 8, 8:52 PM EDT | Flash Flood Warning | PHI | Berks, Chester | 3 hr |
| Aug 8, 9:06 PM EDT | River Flood Warning | PHI | Chester | 9 hr |
| Aug 8, 11:40 PM EDT | Areal Flood Warning | PHI | Chester | 4 hr |
| Aug 9, 12:12 AM EDT | River Flood Warning | PHI | Chester, Delaware | 16 hr |
| Aug 9, 3:31 PM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 108 min |
| Aug 9, 3:50 PM EDT | Flash Flood Warning | PHI | Bucks, Montgomery | 2 hr |
| Aug 9, 4:11 PM EDT | Flash Flood Warning | PHI | Northampton | 100 min |
| Aug 9, 5:30 PM EDT | Flash Flood Warning | PHI | Bucks | 83 min |
| Aug 9, 5:56 PM EDT | River Flood Warning | PHI | Chester | 6 hr |
| Aug 9, 6:46 PM EDT | Areal Flood Warning | PHI | Berks, Bucks, Lehigh, Montgomery | 4 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.