Alert archive / New Jersey / Flash Flood Warnings in 2024

Flash Flood Warning 55, NWS Philadelphia/Mount Holly

August 9, 2024Warren County, New Jersey; Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 9, 2024, 4:11 PM EDT for Warren County, New Jersey; Northampton County, Pennsylvania. It was in force for 100 min. 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, 4:11 PM EDT (20:11 UTC)
Expired
Aug 9, 2024, 5:51 PM EDT
In force
100 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Warren County, NJ, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 124 km from the middle of the area, began a volume at 20:13 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, 8.2 hours before the alert went out and 190 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.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2024-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 988 joules per kilogram.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2024-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 223 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
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

Open this sounding in Storm Lab

The text

As transmitted.

023 
WGUS51 KPHI 092011
FFWPHI
NJC041-PAC095-100015-
/O.NEW.KPHI.FF.W.0055.240809T2011Z-240810T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
411 PM EDT Fri Aug 9 2024

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northern Warren County in northwestern New Jersey...
  Northeastern Northampton County in eastern Pennsylvania...

* Until 815 PM EDT.

* At 411 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Up to 1 inch of rain has 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 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...
  Blairstown, Bangor, Pen Argyl, Belvidere, Hope, East Bangor, 
  Columbia, Millbrook, Roseto and Portland.

This includes Interstate 80 in New Jersey between mile markers 4 and 
15.

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 4083 7528 4087 7528 4088 7527 4089 7524
      4090 7515 4093 7511 4103 7505 4104 7503
      4107 7501 4109 7497 4097 7484 4084 7500
      4076 7518

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...1-2 INCHES IN 1 HOUR

$$

MJL
1 follow-up statement
424 
WGUS71 KPHI 092151
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
551 PM EDT Fri Aug 9 2024

NJC041-PAC095-092201-
/O.CAN.KPHI.FF.W.0055.000000T0000Z-240810T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Warren NJ-Northampton PA-
551 PM EDT Fri Aug 9 2024

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHERN WARREN AND 
NORTHEASTERN 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 4083 7528 4087 7528 4088 7527 4089 7524
      4090 7515 4093 7511 4103 7505 4104 7503
      4107 7501 4109 7497 4097 7484 4084 7500
      4076 7518

$$

MJL

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 9, 3:31 PM EDTFlash Flood WarningPHIWarren108 min
Aug 9, 5:30 PM EDTFlash Flood WarningPHIMercer83 min
Aug 8, 8:52 PM EDTFlash Flood WarningPHIBerks, Chester3 hr
Aug 8, 9:06 PM EDTRiver Flood WarningPHIChester9 hr
Aug 8, 11:40 PM EDTAreal Flood WarningPHIChester4 hr
Aug 9, 12:12 AM EDTRiver Flood WarningPHIChester, Delaware16 hr
Aug 9, 2:50 PM EDTFlash Flood WarningPHILehigh, Northampton2 hr
Aug 9, 3:50 PM EDTFlash Flood WarningPHIBucks, Montgomery2 hr
Aug 9, 5:56 PM EDTRiver Flood WarningPHIChester6 hr
Aug 9, 6:46 PM EDTAreal Flood WarningPHIBerks, Bucks, Lehigh, Montgomery4 hr

Nearby

Flash Flood Warnings in New Jersey, 2024Flash 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.