Alert archive / New Jersey / Flash Flood Warnings in 2018

Flash Flood Warning 99, NWS Philadelphia/Mount Holly

September 18, 2018Mercer County, Middlesex County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at Sep 18, 2018, 12:01 PM EDT for Mercer County, Middlesex County, Somerset County, New Jersey. It was in force for 4 hr. 3 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
Sep 18, 2018, 12:01 PM EDT (16:01 UTC)
Expired
Sep 18, 2018, 4:00 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), 51 km from the middle of the area, began a volume at 16:04 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

TimeReportWhereRemark
Sep 18, 12:46 PM EDTFLASH FLOOD1 Nw Milltown, NJMILLTOWN ROAD CLOSED NORTH OF U.S. HIGHWAY 1 WITH SEVERAL CARS DISABLED FROM FLOOD WATERS.
Sep 18, 1:00 PM EDTFLASH FLOOD1 Nnw North Brunswick T, NJJERSEY AVENUE CLOSED NEAR HURON ROAD FROM FLOODING. TIME APPROXIMATED USING RADAR AND NEARBY REPORTS.
Sep 18, 1:09 PM EDTFLOODSouth Brunswick, NJSTREET FLOODING ON GEORGES ROAD, JUNCTION POND LANE, AND SUMMERFIELD BOULEVARD.

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, 4.0 hours before the alert went out and 151 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-pSkew-T log-p diagram, Brookhaven, NY at 12:00Z on 2018-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1035 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 12:00Z on 2018-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 220 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
1035 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
495 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
220 m²/s²
0-3 km storm-relative helicity
238 m²/s²
Significant tornado parameter
0.8
Supercell composite
4.3

Open this sounding in Storm Lab

The text

As transmitted.

114 
WGUS51 KPHI 181601
FFWPHI
NJC021-023-035-182000-
/O.NEW.KPHI.FF.W.0099.180918T1601Z-180918T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1201 PM EDT TUE SEP 18 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 400 PM EDT.

* At 1200 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Up to two inches of rain have already fallen in the 
  last hour. 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, Rocky Hill,
  Skillman, Princeton Meadows, Kingston, Dayton, Plainsboro Center,
  North Brunswick Township, Kendall Park, South River, Highland Park
  and Metuchen.

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.

Please report flooding to your local law enforcement agency when you
can do so safely.

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 4029 7467 4042 7474 4054 7433 4042 7428

$$

MPS
2 follow-up statements
242 
WGUS71 KPHI 181714
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
114 PM EDT TUE SEP 18 2018

NJC021-023-035-182000-
/O.CON.KPHI.FF.W.0099.000000T0000Z-180918T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Middlesex NJ-
114 PM EDT TUE SEP 18 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 400 PM EDT FOR
NORTH CENTRAL MERCER...SOUTHEASTERN SOMERSET AND CENTRAL MIDDLESEX
COUNTIES...

At 112 PM EDT, Doppler radar indicated the thunderstorms producing 
heavy rain have moved east of the warned area. However, additional 
showers and thunderstorms are possible through the afternoon. It 
will also take time for the water to recede. Therefore, the flash 
flood warning continues. Up to two inches of rain have already 
fallen. 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, Rocky Hill,
Skillman, Princeton Meadows, Kingston, Dayton, Plainsboro Center,
North Brunswick Township, Kendall Park, South River, Highland Park
and Metuchen.

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 4029 7467 4042 7474 4054 7433 4042 7428

$$

SFJ
071 
WGUS71 KPHI 181950
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
350 PM EDT TUE SEP 18 2018

NJC021-023-035-182000-
/O.EXP.KPHI.FF.W.0099.000000T0000Z-180918T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Somerset NJ-Middlesex NJ-
350 PM EDT TUE SEP 18 2018

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL MERCER...SOUTHEASTERN
SOMERSET AND CENTRAL MIDDLESEX COUNTIES WILL EXPIRE AT 400 PM EDT...

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

LAT...LON 4029 7467 4042 7474 4054 7433 4042 7428

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 18, 4:13 AM EDTSpecial Weather StatementPHICamden, Gloucester, Salem92 min
Sep 18, 9:27 AM EDTFlash Flood WatchPHIBurlington, Camden, Gloucester, Hunterdon, Mercer, Middlesex and 5 more6 hr
Sep 18, 10:59 AM EDTAreal Flood AdvisoryPHIHunterdon, Mercer, Middlesex, Monmouth, Somerset4 hr
Sep 18, 12:16 PM EDTSpecial Weather StatementPHIMiddlesex29 min
Sep 18, 12:36 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Mercer, Middlesex, Monmouth and 2 more3 hr
Sep 18, 1:20 PM EDTSpecial Weather StatementPHIBurlington25 min
Sep 18, 1:35 PM EDTSpecial Marine WarningPHI55 min
Sep 18, 2:51 PM EDTSpecial Marine WarningPHI38 min
Sep 18, 2:55 PM EDTSpecial Weather StatementPHIOcean35 min
Sep 18, 3:02 PM EDTAreal Flood AdvisoryPHIBurlington, Ocean3 hr
Sep 18, 3:12 PM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Camden, Ocean47 min
Sep 18, 3:47 PM EDTSpecial Weather StatementPHIOcean28 min
Sep 18, 4:12 PM EDTSpecial Weather StatementPHIAtlantic33 min
Sep 18, 4:47 PM EDTAreal Flood AdvisoryPHIAtlantic, Cape May, Cumberland, Ocean2 hr
Sep 18, 5:17 PM EDTFlash Flood WarningPHIAtlantic113 min

Nearby

Flash Flood Warnings in New Jersey, 2018Every 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.