Alert archive / New Jersey / Flash Flood Warnings in 2026

Flash Flood Warning 51, NWS Philadelphia/Mount Holly

July 18, 2026Mercer County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 18, 2026, 3:14 PM EDT for Mercer County, New Jersey; Bucks County, Pennsylvania. It was in force for 4 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: Jul 18, 2026, 3:14 PM EDT (19:14 UTC)
Expired: Jul 18, 2026, 7:15 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Mercer County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 35 km from the middle of the area, began a volume at 19:14 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
Jul 18, 4:15 PM EDT	FLASH FLOOD	Hamilton Twp, NJ	Flooding at the intersection of East State Street and Nottingham Way leading to a road closure. Time from report.

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 12:00Z, 7.2 hours before the alert went out and 172 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 5 J/kg
Mixed-layer CIN: -238 J/kg
Mixed-layer LCL: 1076 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 131 m²/s²
0-3 km storm-relative helicity: 157 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

As transmitted.

084 
WGUS51 KPHI 181914
FFWPHI
NJC021-PAC017-182315-
/O.NEW.KPHI.FF.W.0051.260718T1914Z-260718T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
314 PM EDT Sat Jul 18 2026

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Southern Mercer County in central New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...

* Until 715 PM EDT.

* At 314 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1 inch of rain 
  has fallen. The expected rainfall rate is 1 to 3 inches in 1 hour. 
  Additional rainfall amounts of 0.5 to 2 inches are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding caused by
           thunderstorms.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets, and underpasses.

* Some locations that may experience flash flooding include...
  Philadelphia, Trenton, Ewing, Burlington, Bristol, Hightstown, 
  Yardley, Newtown, Tullytown, Langhorne, Ivyland and Levittown.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 58 and 66.
	New Jersey Turnpike between exits 8 and 8A.
	Interstate 195 in New Jersey between mile markers 0 and 8.
	Interstate 95 in Pennsylvania between mile markers 38 and 40.
	Pennsylvania Turnpike between mile markers 351 and 359.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around...don't drown when encountering flooded roads. Most 
flood deaths occur in vehicles.

&&

LAT...LON 4029 7456 4029 7453 4027 7448 4024 7448
      4022 7454 4019 7456 4018 7461 4014 7459
      4014 7462 4015 7462 4018 7470 4018 7471
      4016 7471 4014 7474 4012 7479 4013 7482
      4010 7484 4008 7486 4007 7489 4021 7511

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL RATE...1-3 INCHES IN 1 HOUR

$$

Kruzdlo

1 follow-up statement

861 
WGUS71 KPHI 182308
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
708 PM EDT Sat Jul 18 2026

NJC021-PAC017-182318-
/O.EXP.KPHI.FF.W.0051.000000T0000Z-260718T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Bucks PA-
708 PM EDT Sat Jul 18 2026

...FLASH FLOOD WARNING WILL EXPIRE AT 715 PM EDT THIS EVENING FOR 
SOUTHERN MERCER AND SOUTHEASTERN BUCKS COUNTIES...

The heavy rain has ended for the moment. Flood waters have receded. 
But additional rain is possible this evening. As a result, a Flood 
Watch remains in effect until 200 AM EDT Sunday for portions of 
northern Delaware, New Jersey, and Pennsylvania.

&&

LAT...LON 4029 7456 4029 7453 4027 7448 4024 7448
      4022 7454 4019 7456 4018 7461 4014 7459
      4014 7462 4015 7462 4018 7470 4018 7471
      4016 7471 4014 7474 4012 7479 4013 7482
      4010 7484 4008 7486 4007 7489 4021 7511

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 10:39 AM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	21 min
Jul 18, 12:40 PM EDT	Flash Flood Warning	PHI	Middlesex, Morris, Somerset	3 hr
Jul 18, 1:52 PM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Somerset	4 hr
Jul 18, 2:36 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Monmouth	4 hr
Jul 18, 3:13 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	47 min
Jul 18, 3:16 PM EDT	Special Marine Warning	PHI		59 min
Jul 18, 3:30 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden	45 min
Jul 18, 3:31 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Monmouth, Ocean	44 min
Jul 18, 3:36 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester	39 min
Jul 18, 3:44 PM EDT	Flash Flood Warning	PHI	Middlesex, Monmouth, Ocean	4 hr
Jul 18, 4:02 PM EDT	Special Marine Warning	PHI		118 min
Jul 18, 4:03 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Ocean	42 min
Jul 18, 4:34 PM EDT	Flash Flood Warning	PHI	Ocean	4 hr
Jul 18, 4:46 PM EDT	Flash Flood Warning	PHI	Ocean	4 hr
Jul 18, 5:14 PM EDT	Severe Thunderstorm Warning	PHI	Cumberland, Salem	61 min
Jul 18, 5:16 PM EDT	Special Marine Warning	PHI		89 min
Jul 18, 5:47 PM EDT	Special Marine Warning	PHI		118 min
Jul 18, 5:49 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	41 min
Jul 18, 6:30 PM EDT	Special Marine Warning	PHI		2 hr
Jul 18, 6:30 PM EDT	Severe Thunderstorm Warning	PHI	Mercer, Middlesex, Monmouth, Somerset	45 min
Jul 18, 6:55 PM EDT	Areal Flood Warning	PHI	Monmouth	4 hr
Jul 18, 6:56 PM EDT	Special Marine Warning	PHI		64 min
Jul 18, 7:13 PM EDT	Severe Thunderstorm Warning	PHI	Cape May	32 min
Jul 18, 7:47 PM EDT	Areal Flood Warning	PHI	Monmouth, Ocean	4 hr
Jul 18, 2:44 PM EDT	Flash Flood Warning	PHI	Bucks, Montgomery	4 hr
Jul 18, 3:45 PM EDT	Severe Thunderstorm Warning	PHI	Chester	45 min
Jul 18, 5:45 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	45 min

Nearby

Flash Flood Warnings in New Jersey, 2026 Flash Flood Warnings in Pennsylvania, 2026 Every flash flood warning in 2026

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.