Alert archive / New Jersey / Flash Flood Warnings in 2017

Flash Flood Warning 49, NWS Philadelphia/Mount Holly

August 22, 2017Hunterdon County, Middlesex County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 22, 2017, 11:42 PM EDT for Hunterdon County, Middlesex County, Somerset County, New Jersey. It was in force for 4 hr. 4 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: Aug 22, 2017, 11:42 PM EDT (03:42 UTC)
Expired: Aug 23, 2017, 3:45 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Middlesex County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 59 km from the middle of the area, began a volume at 03:46 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, 11:45 PM EDT	FLASH FLOOD	Reaville, NJ	RIVER GAUGE ON THE NESHANIC AT REAVILLE IS ABOVE FLOOD STAGE AND CONTINUING TO RISE.
Aug 22, 11:50 PM EDT	FLOOD	Hillsborough, NJ	MINOR STREET FLOODING REPORTED.
Aug 23, 12:15 AM EDT	FLASH FLOOD	South Amboy, NJ	SEVERAL WATER RESCUES ONGOING IN SOUTH AMBOY AND SAYREVILLE ESPECIALLY IN THE AREA AROUND VICTORY CIRCLE.
Aug 23, 1:24 AM EDT	HEAVY RAIN 1.79	Port Reading, 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 00:00Z, 3.7 hours before the alert went out and 156 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: 1278 J/kg
Mixed-layer CIN: -59 J/kg
Mixed-layer LCL: 845 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 171 m²/s²
0-3 km storm-relative helicity: 220 m²/s²
Significant tornado parameter: 1.1
Supercell composite: 4.6

Open this sounding in Storm Lab

The text

As transmitted.

116 
WGUS51 KPHI 230342
FFWPHI
NJC019-023-035-230745-
/O.NEW.KPHI.FF.W.0049.170823T0342Z-170823T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1142 PM EDT TUE AUG 22 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southeastern Hunterdon County in northwestern New Jersey...
  Southern Somerset County in northern New Jersey...
  Northern Middlesex County in northern New Jersey...

* Until 345 AM EDT

* At 1142 PM EDT...Doppler radar and automated rain gauges indicated
  thunderstorms producing heavy rain across the warned area. Up to
  three inches of rain have already fallen. Flash flooding is
  expected to begin shortly in the areas of heaviest rain.

* Some locations that could experience flooding include...
  New Brunswick, Perth Amboy, Somerville, Somerset, Edison, East
  Brunswick, South Brunswick, Sayreville, North Brunswick, Carteret,
  Middlesex, Bound Brook, Manville, Flemington, Frenchtown, Rocky
  Hill, Stockton, Millstone, Skillman and Flagtown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4056 7421 4055 7425 4050 7426 4050 7428
      4044 7423 4037 7462 4038 7462 4037 7472
      4042 7475 4042 7480 4038 7481 4038 7487
      4035 7486 4034 7494 4040 7496 4040 7504
      4045 7507 4052 7506 4060 7445 4059 7420

$$

CMS

1 follow-up statement

025 
WGUS71 KPHI 230448
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1248 AM EDT WED AUG 23 2017

NJC019-023-035-230745-
/O.CON.KPHI.FF.W.0049.000000T0000Z-170823T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Somerset NJ-Middlesex NJ-
1248 AM EDT WED AUG 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM EDT FOR
SOUTHEASTERN HUNTERDON...SOUTHERN SOMERSET AND NORTHERN MIDDLESEX
COUNTIES...

At 1245 AM EDT...trained weather spotters reported flash flooding in 
South Amboy in Middlesex County, where several water rescues are 
ongoing. Additionally, the gauge on the Neshanic River in Reaville 
is indicating the river has risen above flood stage. Up to three 
inches of rain have already fallen. Flash flooding is already 
occurring.

Some locations that could experience flooding include...
New Brunswick, Perth Amboy, Somerville, Somerset, Edison, East
Brunswick, South Brunswick, Sayreville, North Brunswick, Carteret,
Middlesex, Bound Brook, Manville, Flemington, Frenchtown, Rocky Hill,
Stockton, Millstone, Skillman and Flagtown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4056 7421 4055 7425 4050 7426 4050 7428
      4044 7423 4037 7462 4038 7462 4037 7472
      4042 7475 4042 7480 4038 7481 4038 7487
      4035 7486 4034 7494 4040 7496 4040 7504
      4045 7507 4052 7506 4060 7445 4059 7420

$$

CMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 22, 8:12 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	48 min
Aug 22, 8:15 PM EDT	Tornado Warning	PHI	Warren	30 min
Aug 22, 8:20 PM EDT	Special Weather Statement	PHI	Sussex	40 min
Aug 22, 8:45 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Somerset, Warren	60 min
Aug 22, 8:58 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	24 min
Aug 22, 9:42 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset, Warren	48 min
Aug 22, 10:07 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	53 min
Aug 22, 10:13 PM EDT	Special Marine Warning	PHI		92 min
Aug 22, 10:27 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Somerset	48 min
Aug 22, 10:37 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Somerset	4 hr
Aug 22, 10:40 PM EDT	Areal Flood Advisory	PHI	Mercer	4 hr
Aug 22, 10:58 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Cumberland, Gloucester, Mercer, Middlesex and 1 more	62 min
Aug 22, 11:39 PM EDT	Special Marine Warning	PHI		66 min
Aug 22, 11:46 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Ocean, Salem	44 min
Aug 23, 12:06 AM EDT	Flash Flood Warning	PHI	Camden, Gloucester	4 hr
Aug 23, 12:29 AM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Ocean	46 min
Aug 23, 12:37 AM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Mercer, Middlesex, Monmouth and 1 more	4 hr
Aug 23, 1:56 AM EDT	Areal Flood Advisory	PHI	Salem	4 hr
Aug 23, 2:43 AM EDT	Areal Flood Advisory	PHI	Atlantic, Burlington, Camden, Cumberland, Gloucester, Ocean and 1 more	4 hr
Aug 23, 3:37 AM EDT	Areal Flood Warning	PHI	Hunterdon, Middlesex, Somerset	4 hr
Aug 23, 4:02 AM EDT	Areal Flood Warning	PHI	Camden, Gloucester	4 hr

Nearby

Flash Flood Warnings in New Jersey, 2017 Every flash flood warning in 2017

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.