Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 47, NWS Philadelphia/Mount Holly

August 22, 2021Morris County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 22, 2021, 12:24 AM EDT for Morris County, New Jersey. It was in force for 3 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: Aug 22, 2021, 12:24 AM EDT (04:24 UTC)
Expired: Aug 22, 2021, 3:15 AM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Morris County, NJ

The radar

The Philadelphia radar (KDIX), 109 km from the middle of the area, began a volume at 04:25 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
Aug 22, 1:15 AM EDT	FLASH FLOOD	1 Nne Troy Hills, NJ	ALL LANES OF US 46 CLOSED DUE FLOODING. TIME ESTIMATED FROM RADAR.

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 00:00Z, 4.4 hours before the alert went out and 130 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: 1163 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 543 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 75 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.7

Open this sounding in Storm Lab

The text

As transmitted.

644 
WGUS51 KPHI 220424
FFWPHI
NJC027-220715-
/O.NEW.KPHI.FF.W.0047.210822T0424Z-210822T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1224 AM EDT Sun Aug 22 2021

The National Weather Service in Mount Holly has issued a

* Flash Flood Warning for...
  Northeastern Morris County in northern New Jersey...

* Until 315 AM EDT.

* At 1224 AM EDT, Doppler radar indicated heavy rain across the 
  warned area. Between 1 and 2 inches of rain have fallen. 
  Additional rainfall amounts of 1 to 3 inches 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 will experience flash flooding include...
  Morristown, Dover, Madison, Hopatcong, Florham Park, East Hanover, 
  Lincoln Park, Kinnelon, Boonton, Butler, Wharton, and Rockaway.

This includes the following highways...
	Interstate 80 in New Jersey between mile markers 32 and 48.
	Interstate 287 in New Jersey between mile markers 37 and 53.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4074 7437 4078 7445 4093 7465 4097 7464
      4109 7450 4108 7449 4103 7450 4105 7445
      4104 7443 4102 7443 4100 7430 4097 7428
      4093 7429 4091 7427 4090 7428 4091 7433
      4087 7434 4086 7432 4079 7437

FLASH FLOOD...RADAR INDICATED

$$

BAH

1 follow-up statement

359 
WGUS71 KPHI 220706
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
306 AM EDT Sun Aug 22 2021

NJC027-220716-
/O.EXP.KPHI.FF.W.0047.000000T0000Z-210822T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-
306 AM EDT Sun Aug 22 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 315 AM EDT EARLY THIS MORNING 
FOR NORTHEASTERN MORRIS COUNTY...

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 800 AM Monday.

LAT...LON 4074 7437 4078 7445 4093 7465 4097 7464
      4109 7450 4108 7449 4103 7450 4105 7445
      4104 7443 4102 7443 4100 7430 4097 7428
      4093 7429 4091 7427 4090 7428 4091 7433
      4087 7434 4086 7432 4079 7437

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 9:35 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth, Ocean	3 hr
Aug 21, 10:47 PM EDT	Areal Flood Advisory	PHI	Morris	3 hr
Aug 21, 11:38 PM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Monmouth, Ocean	3 hr
Aug 22, 12:04 AM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Monmouth, Ocean	3 hr
Aug 22, 1:30 AM EDT	Areal Flood Advisory	PHI	Middlesex, Monmouth	4 hr
Aug 22, 1:35 AM EDT	Areal Flood Advisory	PHI	Morris, Somerset	3 hr
Aug 22, 2:04 AM EDT	Flash Flood Warning	PHI	Middlesex, Monmouth	9 hr
Aug 22, 2:09 AM EDT	Flash Flood Warning	PHI	Burlington, Ocean	5 hr
Aug 22, 2:40 AM EDT	Flash Flood Warning	PHI	Hunterdon, Morris, Somerset	5 hr
Aug 22, 3:10 AM EDT	Flash Flood Warning	PHI	Burlington, Hunterdon, Mercer, Monmouth, Ocean	8 hr
Aug 22, 4:21 AM EDT	Flash Flood Warning	PHI	Monmouth, Ocean	3 hr
Aug 22, 5:36 AM EDT	Flash Flood Warning Considerable damage threat	PHI	Mercer, Middlesex, Monmouth, Somerset	5 hr
Aug 22, 6:07 AM EDT	Flash Flood Warning	PHI	Hunterdon, Warren	67 min
Aug 22, 7:52 AM EDT	Areal Flood Warning	PHI	Hunterdon, Somerset	15 hr
Aug 22, 10:43 AM EDT	Special Marine Warning	PHI		62 min
Aug 22, 10:49 AM EDT	Areal Flood Warning	PHI	Middlesex, Monmouth, Somerset	13 hr
Aug 22, 10:52 AM EDT	Areal Flood Warning	PHI	Hunterdon, Mercer, Monmouth	13 hr
Aug 22, 11:06 AM EDT	Special Marine Warning	PHI		54 min
Aug 22, 1:35 PM EDT	Coastal Flood Advisory	PHI	Cape May	10 hr
Aug 22, 1:53 PM EDT	Areal Flood Advisory	PHI	Morris	6 hr
Aug 22, 3:21 PM EDT	River Flood Warning	PHI	Somerset	54 hr
Aug 22, 5:07 PM EDT	Areal Flood Advisory	PHI	Morris, Sussex, Warren	6 hr
Aug 22, 5:48 PM EDT	Flash Flood Warning	PHI	Morris, Sussex, Warren	6 hr

Nearby

Flash Flood Warnings in New Jersey, 2021 Every 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.