Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 303, NWS Philadelphia/Mount Holly

September 13, 2021Middlesex County, Morris County, Somerset County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 13, 2021, 9:34 PM EDT for Middlesex County, Morris County, Somerset County, New Jersey. It was in force for 38 min. 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
Sep 13, 2021, 9:34 PM EDT (01:34 UTC)
Expired
Sep 13, 2021, 10:12 PM EDT
In force
38 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.88 in
Wind
60.0 mph

Counties Middlesex County, NJ, Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 72 km from the middle of the area, began a volume at 01:36 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 13, 9:54 PM EDTTSTM WND DMG1 Sse Edison, NJDOWNED WIRES ON US 1 NORTHBOUND IN EDISON TOWNSHIP NEAR OLD POST ROAD-NORTH. TIME ESTIMATED FROM RADAR.
Sep 13, 10:00 PM EDTTSTM WND DMGHopelawn, NJLARGE TREE FELL THROUGH THE ROOF OF A HOUSE IN HOPELAWN. TIME ESTIMATED FROM RADAR.
Sep 13, 10:00 PM EDTTSTM WND DMGHopelawn, NJTREE FELL THROUGH THE ROOF OF A HOUSE IN HOPELAWN. TIME ESTIMATED FROM RADAR.
Sep 13, 10:00 PM EDTHAIL 0.5Perth Amboy, NJ

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 13, 7:44 PM EDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 1.6 hours before the alert went out and 130 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 00:00Z on 2021-09-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 90 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 00:00Z on 2021-09-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 square meters per square second.19395878Sfc1 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
90 J/kg
Mixed-layer CIN
-236 J/kg
Mixed-layer LCL
1411 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
139 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

088 
WUUS51 KPHI 140134
SVRPHI
NJC023-027-035-140230-
/O.NEW.KPHI.SV.W.0303.210914T0134Z-210914T0230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
934 PM EDT Mon Sep 13 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southern Morris County in northern New Jersey...
  Central Somerset County in northern New Jersey...
  Northeastern Middlesex County in northern New Jersey...

* Until 1030 PM EDT.

* At 933 PM EDT, a severe thunderstorm was located over Martinsville,
  or near Somerville, moving east at 40 mph.

  HAZARD...60 mph wind gusts and nickel size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  New Brunswick, Perth Amboy, Somerville, Somerset, Edison, Carteret,
  Middlesex, Bound Brook, Manville, Millstone, Flagtown, Colonia,
  Martinsville, Millington, Society Hill, Woodbridge, South
  Plainfield, North Plainfield, Highland Park and Metuchen.

This includes the following highways...
 New Jersey Turnpike between exits 11 and 13.
 Interstate 78 in New Jersey between mile markers 34 and 42.
 Interstate 287 in New Jersey between mile markers 0 and 18.
 Garden State Parkway between mile markers 126 and 134.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

In addition to hail and damaging winds, frequent cloud to ground 
lightning is occurring with this storm. Move indoors immediately. 
Remember, if you can hear thunder, you are close enough to be struck 
by lightning.

&&

LAT...LON 4056 7421 4055 7425 4050 7426 4049 7428
      4048 7471 4069 7457 4068 7445 4066 7445
      4066 7440 4063 7442 4060 7446 4061 7431
      4059 7429 4060 7426 4059 7421
TIME...MOT...LOC 0133Z 280DEG 34KT 4064 7454 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse
2 follow-up statements
808 
WWUS51 KPHI 140200
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1000 PM EDT Mon Sep 13 2021

NJC027-140210-
/O.CAN.KPHI.SV.W.0303.000000T0000Z-210914T0230Z/
Morris NJ-
1000 PM EDT Mon Sep 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN MORRIS COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 100 AM EDT for
northern New Jersey.

LAT...LON 4055 7425 4050 7426 4049 7428 4050 7457
      4057 7438 4061 7431 4059 7429 4060 7426
      4059 7421 4056 7421
TIME...MOT...LOC 0200Z 279DEG 34KT 4053 7424 

$$

NJC023-035-140230-
/O.CON.KPHI.SV.W.0303.000000T0000Z-210914T0230Z/
Somerset NJ-Middlesex NJ-
1000 PM EDT Mon Sep 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT
FOR EAST CENTRAL SOMERSET AND NORTHEASTERN MIDDLESEX COUNTIES...

At 1000 PM EDT, a severe thunderstorm was located over Tottenville,
or over Perth Amboy, moving east at 40 mph.

HAZARD...60 mph wind gusts and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
New Brunswick, Perth Amboy, Somerset, Edison, Carteret, Colonia,
Society Hill, Woodbridge, Highland Park, Metuchen, Iselin, Sewaren,
Port Reading, Fords and Avenel.

This includes the following highways...
 New Jersey Turnpike between exits 11 and 13.
 Interstate 287 in New Jersey between mile markers 0 and 4.
 Garden State Parkway between mile markers 127 and 134.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.

&&

LAT...LON 4055 7425 4050 7426 4049 7428 4050 7457
      4057 7438 4061 7431 4059 7429 4060 7426
      4059 7421 4056 7421
TIME...MOT...LOC 0200Z 279DEG 34KT 4053 7424 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.88 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse
091 
WWUS51 KPHI 140212
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1012 PM EDT Mon Sep 13 2021

NJC023-035-140221-
/O.CAN.KPHI.SV.W.0303.000000T0000Z-210914T0230Z/
Somerset NJ-Middlesex NJ-
1012 PM EDT Mon Sep 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL SOMERSET AND
NORTHEASTERN MIDDLESEX COUNTIES IS CANCELLED...
        
The storm which prompted the warning has moved out of the area.
Therefore, this warning has been cancelled.

Another Severe Thunderstorm Warning remains in effect for portions 
of Middlesex County until 1045 PM.

LAT...LON 4055 7425 4050 7426 4049 7428 4050 7457
      4057 7438 4061 7431 4059 7429 4060 7426
      4059 7421 4056 7421
TIME...MOT...LOC 0207Z 280DEG 34KT 4051 7410 

$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 13, 8:41 PM EDTSevere Thunderstorm WarningPHIHunterdon, Warren49 min
Sep 13, 9:03 PM EDTAreal Flood AdvisoryPHIHunterdon, Morris, Somerset, Sussex, Warren109 min
Sep 13, 9:03 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Somerset, Warren57 min
Sep 13, 9:12 PM EDTFlash Flood WarningPHIHunterdon, Morris, Warren114 min
Sep 13, 9:21 PM EDTSevere Thunderstorm WarningPHIHunterdon, Somerset, Warren38 min
Sep 13, 9:53 PM EDTSevere Thunderstorm WarningPHIMercer, Middlesex, Monmouth, Somerset52 min
Sep 13, 10:03 PM EDTSpecial Marine WarningPHI57 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2021Every severe thunderstorm 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.