Alert archive / New Jersey / Flash Flood Warnings in 2018

Flash Flood Warning 52, NWS Philadelphia/Mount Holly

August 4, 2018Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 4, 2018, 9:32 AM EDT for Somerset 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 4, 2018, 9:32 AM EDT (13:32 UTC)
Expired: Aug 4, 2018, 12:11 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 13:32 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 4, 11:15 AM EDT	FLASH FLOOD	North Plainfield, NJ	FLASH FLOODING OCCURRED ALONG GREEN BROOK.

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, 1.5 hours before the alert went out and 139 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: 1326 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 507 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 150 m²/s²
0-3 km storm-relative helicity: 170 m²/s²
Significant tornado parameter: 0.7
Supercell composite: 4.6

Open this sounding in Storm Lab

The text

As transmitted.

926 
WGUS51 KPHI 041332
FFWPHI
NJC035-041730-
/O.NEW.KPHI.FF.W.0052.180804T1332Z-180804T1730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
932 AM EDT SAT AUG 4 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 130 PM EDT.

* At 932 AM EDT, local law enforcement reported flash flooding 
  across the warned area, particularly in the North Plainfield area 
  with cars stuck in water. Although rainfall is tapering off, two 
  to three inches of rain has fallen this morning. Flash flooding is 
  expected to continue.

* Some locations that could experience flooding include...
  Somerville, Middlesex, Bound Brook, Manville, Mendham, Peapack And
  Gladstone, Far Hills, Martinsville, Basking Ridge, North
  Plainfield, Bernardsville and Watchung.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4060 7445 4054 7459 4072 7470 4076 7456
      4070 7451 4068 7453 4065 7452 4067 7448
      4066 7445 4067 7443 4066 7440 4065 7440

$$

Robertson

1 follow-up statement

562 
WGUS71 KPHI 041611
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1211 PM EDT SAT AUG 4 2018

NJC035-041616-
/O.CAN.KPHI.FF.W.0052.000000T0000Z-180804T1730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Somerset NJ-
1211 PM EDT SAT AUG 4 2018

...THE FLASH FLOOD WARNING FOR NORTHEASTERN SOMERSET COUNTY IS
CANCELLED...

The heavy rain has ended and the threat for flash flooding has 
ended. However, there remains some local flooding across the area, 
and several creeks and streams continue to rise, including Green 
Brook near Plainfield. An Areal Flood Warning will be issued for the 
residual creek and stream flooding.

LAT...LON 4060 7445 4054 7459 4072 7470 4076 7456
      4070 7451 4068 7453 4065 7452 4067 7448
      4066 7445 4067 7443 4066 7440 4065 7440

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 3, 9:10 PM EDT	Areal Flood Advisory	PHI	Sussex, Warren	4 hr
Aug 3, 10:07 PM EDT	Special Weather Statement	PHI	Warren	53 min
Aug 3, 10:35 PM EDT	Special Weather Statement	PHI	Morris, Sussex, Warren	55 min
Aug 4, 2:53 AM EDT	Areal Flood Advisory	PHI	Warren	4 hr
Aug 4, 3:09 AM EDT	Special Weather Statement	PHI	Warren	51 min
Aug 4, 3:14 AM EDT	Areal Flood Advisory	PHI	Sussex	4 hr
Aug 4, 3:55 AM EDT	Special Weather Statement	PHI	Sussex	65 min
Aug 4, 3:58 AM EDT	Areal Flood Warning	PHI	Sussex, Warren	33 hr
Aug 4, 5:12 AM EDT	Areal Flood Advisory	PHI	Morris	3 hr
Aug 4, 5:45 AM EDT	Areal Flood Advisory	PHI	Hunterdon	7 hr
Aug 4, 5:56 AM EDT	Areal Flood Advisory	PHI	Morris	3 hr
Aug 4, 6:19 AM EDT	Flash Flood Warning	PHI	Morris	4 hr
Aug 4, 6:55 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Somerset	4 hr
Aug 4, 8:19 AM EDT	Areal Flood Advisory	PHI	Middlesex, Somerset	4 hr
Aug 4, 9:39 AM EDT	Small Craft Advisory	PHI		6 hr
Aug 4, 10:16 AM EDT	Areal Flood Warning	PHI	Morris	4 hr
Aug 4, 10:51 AM EDT	Areal Flood Warning	PHI	Hunterdon, Somerset	4 hr
Aug 4, 12:13 PM EDT	Areal Flood Warning	PHI	Middlesex, Somerset	2 hr
Aug 4, 4:41 PM EDT	Severe Thunderstorm Warning	PHI	Warren	34 min
Aug 4, 5:04 PM EDT	Special Weather Statement	PHI	Hunterdon	56 min

Nearby

Flash Flood Warnings in New Jersey, 2018 Every flash flood warning in 2018

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.