Alert archive / New Jersey / Flash Flood Warnings in 2019

Flash Flood Warning 17, NWS Philadelphia/Mount Holly

June 18, 2019Mercer County, Middlesex County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Jun 18, 2019, 1:51 PM EDT for Mercer County, Middlesex County, Somerset County, New Jersey. It was in force for 4 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: Jun 18, 2019, 1:51 PM EDT (17:51 UTC)
Expired: Jun 18, 2019, 5:45 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Mercer County, NJ, Middlesex County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 54 km from the middle of the area, began a volume at 17:54 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
Jun 18, 2:49 PM EDT	FLOOD	Rocky Hill, NJ	MPING REPORT OF STREET FLOODING WITH ROADS CLOSED AND VEHICLES STRANDED.

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, 5.9 hours before the alert went out and 141 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: 78 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 453 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 93 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.0

Open this sounding in Storm Lab

The text

As transmitted.

100 
WGUS51 KPHI 181751
FFWPHI
NJC021-023-035-182145-
/O.NEW.KPHI.FF.W.0017.190618T1751Z-190618T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
151 PM EDT Tue Jun 18 2019

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  North central Mercer County in central New Jersey...
  Southern Somerset County in northern New Jersey...
  Central Middlesex County in northern New Jersey...

* Until 545 PM EDT.

* At 151 PM EDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to one inch of rain has
  already fallen. Flash flooding is expected to begin shortly in the
  areas of heaviest rain.

* Some locations that could experience flooding include...
  New Brunswick, Somerset, Edison, Old Bridge, East Brunswick, South
  Brunswick, Sayreville, North Brunswick, Princeton, Matawan,
  Jamesburg, Hopewell, Rocky Hill, Skillman, Brownville, Kingston,
  Dayton, Plainsboro Center, North Brunswick Township and Kendall
  Park.

Additional rainfall amounts of one to two inches are possible in the 
warned area.

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.

&&

LAT...LON 4044 7424 4040 7425 4038 7429 4031 7472
      4042 7479 4042 7475 4044 7475 4055 7437
      4050 7428 4047 7427 4045 7423

$$

SFJ

2 follow-up statements

272 
WGUS71 KPHI 181845
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
245 PM EDT Tue Jun 18 2019

NJC021-023-035-182145-
/O.CON.KPHI.FF.W.0017.000000T0000Z-190618T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Middlesex NJ-
245 PM EDT Tue Jun 18 2019

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM EDT FOR
NORTH CENTRAL MERCER...SOUTHERN SOMERSET AND CENTRAL MIDDLESEX
COUNTIES...

At 244 PM EDT, Doppler radar indicated the thunderstorms producing 
heavy rain had mostly left the warned area. However, up to two 
inches of rain has already fallen, and additional light rain will 
move through the warned area. Flash flooding is expected to begin 
shortly.

Some locations that could experience flooding include...
New Brunswick, Somerset, Edison, Old Bridge, East Brunswick, South
Brunswick, Sayreville, North Brunswick, Princeton, Matawan,
Jamesburg, Hopewell, Rocky Hill, Skillman, Brownville, Kingston,
Dayton, Plainsboro Center, North Brunswick Township and Kendall Park.

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.

&&

LAT...LON 4044 7424 4040 7425 4038 7429 4031 7472
      4042 7479 4042 7475 4044 7475 4055 7437
      4050 7428 4047 7427 4045 7423

$$

SFJ

551 
WGUS71 KPHI 182137
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
537 PM EDT Tue Jun 18 2019

NJC021-023-035-182145-
/O.EXP.KPHI.FF.W.0017.000000T0000Z-190618T2145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Middlesex NJ-
537 PM EDT Tue Jun 18 2019

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL MERCER...SOUTHERN
SOMERSET AND CENTRAL MIDDLESEX COUNTIES WILL EXPIRE AT 545 PM EDT...

The heaviest rain has ended. Although minor street flooding remains 
possible, the threat for more significant flooding has diminished. A 
flood advisory remains in effect. Please continue to heed any 
remaining road closures.

LAT...LON 4044 7424 4040 7425 4038 7429 4031 7472
      4042 7479 4042 7475 4044 7475 4055 7437
      4050 7428 4047 7427 4045 7423

$$

SFJ

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 17, 10:28 PM EDT	Special Marine Warning	PHI		32 min
Jun 18, 11:07 AM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	4 hr
Jun 18, 12:38 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	7 hr
Jun 18, 2:06 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth, Somerset	54 min
Jun 18, 2:11 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth, Ocean	4 hr
Jun 18, 2:35 PM EDT	Special Marine Warning	PHI		70 min
Jun 18, 2:36 PM EDT	Flash Flood Warning	PHI	Middlesex, Monmouth	3 hr
Jun 18, 3:26 PM EDT	Flash Flood Warning	PHI	Hunterdon, Mercer, Somerset	4 hr
Jun 18, 3:41 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	4 hr
Jun 18, 3:57 PM EDT	Flash Flood Warning	PHI	Hunterdon, Warren	4 hr
Jun 18, 4:25 PM EDT	Special Weather Statement	PHI	Mercer	35 min
Jun 18, 5:00 PM EDT	Areal Flood Advisory	PHI	Burlington, Mercer, Monmouth, Ocean	67 min
Jun 18, 6:39 PM EDT	Areal Flood Warning	PHI	Hunterdon, Somerset	4 hr
Jun 18, 7:24 PM EDT	Areal Flood Warning	PHI	Hunterdon, Mercer, Somerset	4 hr

Nearby

Flash Flood Warnings in New Jersey, 2019 Every flash flood warning in 2019

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.