Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 87, NWS Philadelphia/Mount Holly

September 23, 20216 counties in New Jersey; Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 23, 2021, 3:26 PM EDT for 6 counties in New Jersey; Bucks County, Pennsylvania. It was in force for 2 hr. 5 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
Sep 23, 2021, 3:26 PM EDT (19:26 UTC)
Expired
Sep 23, 2021, 5:54 PM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Burlington County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 62 km from the middle of the area, began a volume at 19:28 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

TimeReportWhereRemark
Sep 23, 3:45 PM EDTFLOOD1 Nne Burlington Twp, NJPINEWALD LANE FLOODED. TIME BASED ON SOCIAL MEDIA REPORT.
Sep 23, 3:45 PM EDTFLASH FLOOD2 Sse Bethlehem Twp, NJINTERSTATE 78 RAMP TO PATTENBURG ROAD CLOSED FROM FLOODING. TIME ESTIMATED FROM RADAR.
Sep 23, 3:50 PM EDTFLOODBurlington Twp, NJSTREET FLOODING ON PINEWALD LANE.
Sep 23, 4:27 PM EDTFLASH FLOODPrinceton Junction, NJWASHINGTON ROAD CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT.
Sep 23, 5:27 PM EDTHEAVY RAIN 1.25Mercerville, NJ

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, 7.4 hours before the alert went out and 176 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 2021-09-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 2021-09-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 249 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
103 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
687 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
249 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

958 
WGUS51 KPHI 231926
FFWPHI
NJC005-019-021-023-027-035-PAC017-232330-
/O.NEW.KPHI.FF.W.0087.210923T1926Z-210923T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
326 PM EDT Thu Sep 23 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Mercer County in central New Jersey...
  Southwestern Middlesex County in northern New Jersey...
  Southwestern Morris County in northern New Jersey...
  Western Somerset County in northern New Jersey...
  Hunterdon County in northwestern New Jersey...
  North Central Burlington County in southern New Jersey...
  Central Bucks County in southeastern Pennsylvania...

* Until 730 PM EDT.

* At 326 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen and an additional inch or so is expected over the next 
  hour. Flash flooding is ongoing or expected to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  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, Princeton, Florence, Burlington, Bristol, 
  Doylestown, Byram, Bedminster, Hightstown, Flemington, and Tinicum.

This includes the following highways...
	New Jersey Turnpike between exits 6 and 8.
	Pennsylvania Turnpike between mile markers 355 and 359.
	Interstate 95 in Pennsylvania near mile marker 40.
	Interstate 78 in New Jersey between mile markers 8 and 28.
	Interstate 295 in New Jersey between mile markers 48 and 76.
	Interstate 195 in New Jersey between mile markers 0 and 7.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4029 7450 4018 7459 4018 7461 4017 7460
      3997 7476 4009 7486 4051 7535 4060 7519
      4060 7518 4062 7516 4071 7497 4082 7479

FLASH FLOOD...RADAR INDICATED

$$

NC
1 follow-up statement
403 
WGUS71 KPHI 232154
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
554 PM EDT Thu Sep 23 2021

NJC005-019-021-023-027-035-PAC017-232204-
/O.CAN.KPHI.FF.W.0087.000000T0000Z-210923T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Burlington NJ-Hunterdon NJ-Mercer NJ-Middlesex NJ-Morris NJ-Somerset
NJ-Bucks PA-
554 PM EDT Thu Sep 23 2021

...FLASH FLOOD WARNING IS CANCELLED FOR MERCER, SOUTHWESTERN 
MIDDLESEX, SOUTHWESTERN MORRIS, WESTERN SOMERSET, HUNTERDON, NORTH 
CENTRAL BURLINGTON, AND CENTRAL BUCKS COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flash Flood Watch remains in effect until 200 AM EDT Friday for 
portions of northern Delaware...and southeast Pennsylvania.

A Flash Flood Watch remains in effect until 500 AM EDT Friday for 
portions of central New Jersey...northern New Jersey...and northwest 
New Jersey.

A Flash Flood Watch remains in effect until 200 AM EDT Friday for 
portions of east central Pennsylvania...northeast Pennsylvania...and 
southeast Pennsylvania.

LAT...LON 4029 7450 4018 7459 4018 7461 4017 7460
      3997 7476 4009 7486 4051 7535 4060 7519
      4060 7518 4062 7516 4071 7497 4082 7479

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 22, 8:43 PM EDTGale WarningPHI18 hr
Sep 23, 9:12 AM EDTCoastal Flood AdvisoryPHIBurlington, Camden, Gloucester10 hr
Sep 23, 11:33 AM EDTAreal Flood AdvisoryPHICumberland, Gloucester, Salem3 hr
Sep 23, 11:57 AM EDTFlash Flood WarningPHIGloucester, Salem3 hr
Sep 23, 12:12 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem48 min
Sep 23, 12:54 PM EDTSpecial Weather StatementPHIGloucester51 min
Sep 23, 12:56 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Hunterdon, Mercer, Warren3 hr
Sep 23, 1:13 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Salem47 min
Sep 23, 1:42 PM EDTFlash Flood WarningPHIBurlington, Camden, Gloucester4 hr
Sep 23, 1:58 PM EDTSpecial Weather StatementPHICamden, Hunterdon32 min
Sep 23, 2:37 PM EDTAreal Flood AdvisoryPHIBurlington, Hunterdon, Mercer, Middlesex, Monmouth, Morris and 3 more3 hr
Sep 23, 2:47 PM EDTSpecial Weather StatementPHIHunterdon, Mercer28 min
Sep 23, 2:52 PM EDTSpecial Weather StatementPHICamden23 min
Sep 23, 3:13 PM EDTSpecial Weather StatementPHIMercer, Somerset32 min
Sep 23, 3:16 PM EDTSpecial Weather StatementPHIBurlington29 min
Sep 23, 3:23 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Middlesex, Morris, Somerset52 min
Sep 23, 3:50 PM EDTSpecial Weather StatementPHIBurlington25 min
Sep 23, 4:21 PM EDTAreal Flood AdvisoryPHIMiddlesex, Monmouth, Morris, Ocean, Somerset, Sussex15 min
Sep 23, 4:36 PM EDTFlash Flood WarningPHIMiddlesex, Monmouth, Morris, Somerset, Sussex3 hr
Sep 23, 5:00 PM EDTSpecial Weather StatementPHIMonmouth30 min
Sep 23, 10:52 AM EDTAreal Flood AdvisoryPHIChester3 hr
Sep 23, 11:40 AM EDTAreal Flood AdvisoryPHIBerks, Bucks, Carbon, Lehigh, Montgomery, Northampton3 hr
Sep 23, 12:28 PM EDTFlash Flood WarningPHIChester, Delaware, Montgomery, Philadelphia4 hr
Sep 23, 12:57 PM EDTSpecial Weather StatementPHIBucks33 min
Sep 23, 1:48 PM EDTRiver Flood WarningPHIChester5 hr
Sep 23, 4:26 PM EDTAreal Flood WarningPHIChester, Delaware, Montgomery, Philadelphia80 min
Sep 23, 7:18 PM EDTAreal Flood WarningPHIBerks, Montgomery36 min

Nearby

Flash Flood Warnings in New Jersey, 2021Flash Flood Warnings in Pennsylvania, 2021Every flash flood warning in 2021

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.