Alert archive / New Jersey / Flash Flood Warnings in 2025

Flash Flood Warning 5, NWS Philadelphia/Mount Holly

May 15, 2025Burlington County, Mercer County, Monmouth County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at May 15, 2025, 4:56 PM EDT for Burlington County, Mercer County, Monmouth County, New Jersey; Bucks County, Pennsylvania. It was in force for 44 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
May 15, 2025, 4:56 PM EDT (20:56 UTC)
Expired
May 15, 2025, 5:40 PM EDT
In force
44 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Burlington County, NJ, Mercer County, NJ, Monmouth County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 42 km from the middle of the area, began a volume at 20:59 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, 8.9 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.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2025-05-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 111 joules per kilogram.LCLLFCEL10008507005003002001001 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 2025-05-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 49 square meters per square second.1939Sfc1 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
111 J/kg
Mixed-layer CIN
-56 J/kg
Mixed-layer LCL
507 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
49 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

329 
WGUS51 KPHI 152056
FFWPHI
NJC005-021-025-PAC017-160100-
/O.NEW.KPHI.FF.W.0005.250515T2056Z-250516T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service New York NY
456 PM EDT Thu May 15 2025

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southern Mercer County in central New Jersey...
  Western Monmouth County in central New Jersey...
  North Central Burlington County in southern New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...

* Until 900 PM EDT.

* At 456 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Between 0.5 and 1 inch of rain has fallen. The 
  expected rainfall rate is 1 to 2 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 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...
  Trenton, Ewing, Bordentown, Pennington, Yardley, Newtown, 
  Tullytown, Allentown, Langhorne, White Horse, Mercerville-Hamilton 
  Square and Florence-Roebling.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 4031 7484 4032 7481 4030 7468 4027 7464
      4022 7458 4020 7454 4016 7453 4012 7456
      4008 7462 4010 7470 4013 7483 4018 7497
      4023 7497 4029 7492 4030 7489

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

$$

Hoeflich
1 follow-up statement
147 
WGUS71 KPHI 152140
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
540 PM EDT Thu May 15 2025

NJC005-021-025-PAC017-152150-
/O.CAN.KPHI.FF.W.0005.000000T0000Z-250516T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-Mercer NJ-Monmouth NJ-Bucks PA-
540 PM EDT Thu May 15 2025

...FLASH FLOOD WARNING IS CANCELLED FOR MERCER, WESTERN MONMOUTH, 
NORTH CENTRAL BURLINGTON AND SOUTHEASTERN BUCKS 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.

&&

LAT...LON 4018 7497 4023 7497 4029 7492 4030 7488
      4025 7484 4022 7477 4019 7475 4016 7472
      4018 7470 4014 7462 4014 7459 4018 7461
      4019 7457 4021 7455 4020 7454 4016 7453
      4012 7456 4008 7462 4013 7483

$$

RCM

The office that day

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

IssuedProductOfficeCountiesLasted
May 14, 8:16 PM EDTDense Fog AdvisoryPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 5 more13 hr
May 15, 9:34 AM EDTCoastal Flood AdvisoryPHIBurlington46 hr

Nearby

Flash Flood Warnings in New Jersey, 2025Flash Flood Warnings in Pennsylvania, 2025Every flash flood warning in 2025

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.