Alert archive / New Jersey / Flash Flood Warnings in 2021

Flash Flood Warning 18, NWS Philadelphia/Mount Holly

July 12, 2021Morris County, Sussex County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 12, 2021, 7:11 PM EDT for Morris County, Sussex County, New Jersey. It was in force for 35 min. 2 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 12, 2021, 7:11 PM EDT (23:11 UTC)
Expired: Jul 12, 2021, 7:46 PM EDT
In force: 35 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Morris County, NJ, Sussex County, NJ

The radar

The Philadelphia radar (KDIX), 116 km from the middle of the area, began a volume at 23:13 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 12, 7:49 PM EDT	FLASH FLOOD	2 Wsw Bloomingdale, NJ	FLOODING ON NJ 23 NORTHBOUND. ALL LANES CLOSED.
Jul 12, 7:50 PM EDT	FLOOD	Jefferson Twp, NJ	FLOODING ON BERKSHIRE VALLEY ROAD.

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, 11.2 hours before the alert went out and 132 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: 857 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 697 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

913 
WGUS51 KPHI 122311
FFWPHI
NJC027-037-130300-
/O.NEW.KPHI.FF.W.0018.210712T2311Z-210713T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
711 PM EDT Mon Jul 12 2021

The National Weather Service in Mount Holly has issued a

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

* Until 1100 PM EDT.

* At 711 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. 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...
  Hopatcong, Lincoln Park, Kinnelon, Boonton, Butler, Rockaway, 
  Franklin, Mountain Lakes, Riverdale, Ogdensburg, Lake Telemark, 
  and Green Pond.

This includes the following highways...
	Interstate 80 in New Jersey between mile markers 37 and 39.
	Interstate 287 in New Jersey between mile markers 44 and 53.

This includes the following streams and drainages...
  Middle Delaware-Musconetcong, Hackensack-Passaic, and Rondout.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Motorists should not attempt to drive around barricades or drive 
cars through flooded areas.

&&

LAT...LON 4099 7468 4107 7461 4112 7454 4109 7449
      4103 7450 4105 7445 4104 7443 4102 7443
      4103 7442 4100 7430 4098 7430 4097 7428
      4093 7429 4091 7427 4090 7428 4091 7433
      4087 7434 4089 7449

FLASH FLOOD...RADAR INDICATED

$$

Iovino

1 follow-up statement

199 
WGUS71 KPHI 122346
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
746 PM EDT Mon Jul 12 2021

NJC027-037-122356-
/O.CAN.KPHI.FF.W.0018.000000T0000Z-210713T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Morris NJ-Sussex NJ-
746 PM EDT Mon Jul 12 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHEASTERN MORRIS AND 
SOUTHEASTERN SUSSEX COUNTIES...

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


LAT...LON 4099 7468 4107 7461 4112 7454 4109 7449
      4103 7450 4105 7445 4104 7443 4102 7443
      4103 7442 4100 7430 4098 7430 4097 7428
      4093 7429 4091 7427 4090 7428 4091 7433
      4087 7434 4089 7449

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 1:59 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden	3 hr
Jul 12, 2:12 PM EDT	Flash Flood Warning Emergency	PHI	Burlington	7 hr
Jul 12, 2:20 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth	3 hr
Jul 12, 2:37 PM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Monmouth	93 min
Jul 12, 3:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	67 min
Jul 12, 3:31 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	41 min
Jul 12, 4:26 PM EDT	Special Marine Warning	PHI		2 hr
Jul 12, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	42 min
Jul 12, 4:52 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	98 min
Jul 12, 5:08 PM EDT	Areal Flood Advisory	PHI	Sussex	5 hr
Jul 12, 5:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Mercer	67 min
Jul 12, 5:26 PM EDT	Areal Flood Advisory	PHI	Camden	2 hr
Jul 12, 5:36 PM EDT	Special Weather Statement	PHI	Sussex	24 min
Jul 12, 5:41 PM EDT	Areal Flood Advisory	PHI	Burlington	83 min
Jul 12, 5:57 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	63 min
Jul 12, 6:01 PM EDT	Flash Flood Warning	PHI	Camden	102 min
Jul 12, 6:08 PM EDT	Areal Flood Advisory	PHI	Morris	98 min
Jul 12, 6:43 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	93 min
Jul 12, 6:52 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	34 min
Jul 12, 7:00 PM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	112 min
Jul 12, 7:06 PM EDT	Severe Thunderstorm Warning	PHI	Salem	69 min
Jul 12, 7:33 PM EDT	Special Marine Warning	PHI		58 min

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.