Alert archive / New Jersey / Flash Flood Warnings in 2023

Flash Flood Warning 55, NWS Philadelphia/Mount Holly

July 15, 2023Mercer County, New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 15, 2023, 6:09 PM EDT for Mercer County, New Jersey; Bucks County, Pennsylvania. It was in force for 4 hr. 8 reports 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 15, 2023, 6:09 PM EDT (22:09 UTC)
Expired: Jul 15, 2023, 10:15 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), 54 km from the middle of the area, began a volume at 22:08 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 15, 6:30 PM EDT	FLOOD	2 Wsw Trenton Mercer Ai, NJ	NJ Route 29 near Duffield Drive closed due to flooding.
Jul 15, 7:02 PM EDT	FLASH FLOOD	1 Nw Yardley, PA	Trained Spotter reports impassable roads with water rescues occurring on Taylorsville Road, just off of the I-295 exit.
Jul 15, 7:05 PM EDT	FLOOD	Pennington, NJ	NJ Route 31 at Delaware Avenue in Pennington is impassible due to flood waters. Report relayed via NWS Employee. Photo shows about 1 to 2 feet of standing water in the intersection.
Jul 15, 7:30 PM EDT	RAIN 3.65	Washington Crossing, NJ	Storm total.
Jul 15, 7:39 PM EDT	RAIN 4.66	2 Ese Washington Crossi, NJ	Storm total.
Jul 15, 8:53 PM EDT	RAIN 2.69	Trenton Mercer Airport, NJ	ASOS station KTTN Trenton.
Jul 15, 9:00 PM EDT	RAIN 4.64	Washington Crossing, PA	Mesonet station WASN4 Washington Crossing.
Jul 15, 9:39 PM EDT	RAIN 4.4	2 Ese Washington Crossi, NJ	Mesonet station GW1897 EWING.

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, 10.2 hours before the alert went out and 179 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: 1125 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 596 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 100 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

141 
WGUS51 KPHI 152209
FFWPHI
NJC021-PAC017-160215-
/O.NEW.KPHI.FF.W.0055.230715T2209Z-230716T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
609 PM EDT Sat Jul 15 2023

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  West Central Mercer County in central New Jersey...
  East Central Bucks County in southeastern Pennsylvania...

* Until 1015 PM EDT.

* At 609 PM EDT, Local law enforcement reported thunderstorms 
  producing heavy rain across the warned area. Between 2 and 4 
  inches of rain have fallen. Flash flooding is already occurring. 
  Numerous reports of flooding and water rescues also.

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

  SOURCE...Law enforcement reported.

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

* Some locations that may experience flash flooding include...
  Trenton, Ewing, Pennington, Yardley, Newtown, Washington Crossing, 
  Woodside, Lawrenceville, Woodbourne, and Newtown Grant.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 69 and 76.

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 4035 7485 4036 7484 4036 7483 4031 7467
      4021 7487 4021 7493 4025 7496

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

PO

2 follow-up statements

997 
WGUS71 KPHI 152303
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
703 PM EDT Sat Jul 15 2023

NJC021-PAC017-160215-
/O.CON.KPHI.FF.W.0055.000000T0000Z-230716T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Bucks PA-
703 PM EDT Sat Jul 15 2023

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM EDT THIS 
EVENING FOR WEST CENTRAL MERCER AND EAST CENTRAL BUCKS COUNTIES...

At 703 PM EDT, local law enforcement reported thunderstorms 
producing heavy rain across the warned area. Between 2 and 5 inches 
of rain have fallen. Flash flooding is already occurring.

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

SOURCE...Law enforcement reported.

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

Some locations that may experience flash flooding include...
  Trenton, Ewing, Pennington, Yardley, Newtown, Washington Crossing, 
  Woodside, Lawrenceville, Woodbourne, and Newtown Grant.

This includes the following highways...
	Interstate 295 in New Jersey between mile markers 69 and 76.

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.

&&

LAT...LON 4035 7485 4036 7484 4036 7483 4031 7467
      4021 7487 4021 7493 4025 7496

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Staarmann

156 
WGUS71 KPHI 160209
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1009 PM EDT Sat Jul 15 2023

NJC021-PAC017-160219-
/O.EXP.KPHI.FF.W.0055.000000T0000Z-230716T0215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Bucks PA-
1009 PM EDT Sat Jul 15 2023

...FLASH FLOOD WARNING WILL EXPIRE AT 1015 PM EDT THIS EVENING FOR 
WEST CENTRAL MERCER AND EAST CENTRAL BUCKS COUNTIES...

The heavy rain has ended, and flood waters are receding. Flooding is 
no longer expected to pose a threat.

Additional heavy rain is forecast in the area overnight and Sunday. 
Remain alert for additional warnings and potential for additional 
flooding.

A Flood Watch remains in effect until midnight Sunday night.

LAT...LON 4035 7485 4036 7484 4036 7483 4031 7467
      4021 7487 4021 7493 4025 7496

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 14, 8:05 PM EDT	Special Weather Statement	PHI	Morris	40 min
Jul 14, 8:29 PM EDT	Flash Flood Warning	PHI	Morris	4 hr
Jul 14, 9:13 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Somerset, Warren	3 hr
Jul 14, 9:51 PM EDT	Special Weather Statement	PHI	Morris, Somerset	24 min
Jul 14, 9:57 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Morris, Somerset	41 min
Jul 14, 11:32 PM EDT	Special Weather Statement	PHI	Mercer, Monmouth	28 min
Jul 15, 3:44 AM EDT	Flood Watch	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 10 more	38 hr
Jul 15, 1:33 PM EDT	Special Marine Warning	PHI		57 min
Jul 15, 1:43 PM EDT	Special Weather Statement	PHI	Salem	32 min
Jul 15, 2:56 PM EDT	Special Weather Statement	PHI	Mercer	34 min
Jul 15, 3:08 PM EDT	Special Weather Statement	PHI	Hunterdon	37 min
Jul 15, 3:22 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Somerset	38 min
Jul 15, 3:29 PM EDT	Special Marine Warning	PHI		61 min
Jul 15, 3:30 PM EDT	Special Weather Statement	PHI	Salem	30 min
Jul 15, 3:40 PM EDT	Severe Thunderstorm Warning	PHI	Cumberland, Salem	65 min
Jul 15, 4:08 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Somerset	67 min
Jul 15, 4:11 PM EDT	Special Weather Statement	PHI	Gloucester	34 min
Jul 15, 4:31 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer	106 min
Jul 15, 4:52 PM EDT	Special Weather Statement	PHI	Cumberland	23 min
Jul 15, 4:53 PM EDT	Special Weather Statement	PHI	Middlesex	37 min
Jul 15, 5:00 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Somerset	2 hr
Jul 15, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	Mercer, Middlesex	63 min
Jul 15, 5:18 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Somerset	4 hr
Jul 15, 5:27 PM EDT	Areal Flood Advisory	PHI	Cumberland, Salem	99 min
Jul 15, 5:45 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Sussex, Warren	45 min
Jul 15, 5:49 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	41 min
Jul 15, 6:21 PM EDT	Special Weather Statement	PHI	Mercer	24 min
Jul 14, 8:50 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh, Monroe, Northampton	3 hr
Jul 15, 1:46 PM EDT	Special Weather Statement	PHI	Montgomery	29 min
Jul 15, 3:35 PM EDT	Special Weather Statement	PHI	Berks	25 min
Jul 15, 3:51 PM EDT	Special Weather Statement	PHI	Bucks	24 min
Jul 15, 7:46 PM EDT	Special Weather Statement	PHI	Carbon	29 min
Jul 15, 7:53 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	52 min

Nearby

Flash Flood Warnings in New Jersey, 2023 Flash Flood Warnings in Pennsylvania, 2023 Every flash flood warning in 2023

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.