Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 311, NWS Philadelphia/Mount Holly

September 23, 20215 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 23, 2021, 3:23 PM EDT for 5 counties in New Jersey. It was in force for 52 min. 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 23, 2021, 3:23 PM EDT (19:23 UTC)
Expired: Sep 23, 2021, 4:15 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 19:22 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
Sep 23, 3:24 PM EDT	TSTM WND DMG	1 Nw Skillman, NJ	DOWNED TREE LIMBS AND WIRES NEAR SERVIS ROAD. TIME ESTIMATED FROM RADAR.
Sep 23, 3:26 PM EDT	TSTM WND DMG	1 S Montgomery Twp, NJ	DOWNED WIRES NEAR U.S. HIGHWAY 206 AND SUNSET ROAD. TIME ESTIMATED FROM RADAR.
Sep 23, 3:28 PM EDT	TSTM WND DMG	2 W Kendall Park, NJ	DOWNED TREE LIMBS AND WIRES NEAR BUNKER HILL ROAD. TIME ESTIMATED FROM OUTAGE REPORT AND RADAR.

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, 7.4 hours before the alert went out and 140 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: 103 J/kg
Mixed-layer CIN: -11 J/kg
Mixed-layer LCL: 687 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 249 m²/s²
0-3 km storm-relative helicity: 201 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.1

Open this sounding in Storm Lab

The text

As transmitted.

237 
WUUS51 KPHI 231923
SVRPHI
NJC019-021-023-027-035-232015-
/O.NEW.KPHI.SV.W.0311.210923T1923Z-210923T2015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
323 PM EDT Thu Sep 23 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Eastern Hunterdon County in northwestern New Jersey...
  Southern Morris County in northern New Jersey...
  North central Mercer County in central New Jersey...
  Somerset County in northern New Jersey...
  Northwestern Middlesex County in northern New Jersey...

* Until 415 PM EDT.

* At 323 PM EDT, a severe thunderstorm was located over Skillman, or
  12 miles north of Trenton, moving north at 35 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Somerville, Somerset, Bridgewater, Madison, Middlesex, Princeton,
  Bound Brook, Manville, Chatham, Mendham, Pennington, Peapack And
  Gladstone, Hopewell, Chester, Far Hills, Rocky Hill, Millstone,
  Skillman, Flagtown and Kingston.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 24 and 42.
 Interstate 287 in New Jersey between mile markers 8 and 34.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4073 7437 4067 7446 4066 7445 4067 7443
      4066 7442 4060 7445 4060 7446 4059 7445
      4028 7464 4032 7483 4081 7477 4075 7436
TIME...MOT...LOC 1923Z 194DEG 31KT 4039 7469 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann

4 follow-up statements

220 
WWUS51 KPHI 231935
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
335 PM EDT Thu Sep 23 2021

NJC021-231944-
/O.CAN.KPHI.SV.W.0311.000000T0000Z-210923T2015Z/
Mercer NJ-
335 PM EDT Thu Sep 23 2021

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

LAT...LON 4073 7437 4067 7446 4066 7445 4067 7443
      4066 7442 4036 7459 4037 7462 4039 7463
      4039 7467 4042 7475 4043 7479 4081 7477
      4075 7436
TIME...MOT...LOC 1934Z 194DEG 31KT 4049 7466 

$$

NJC019-023-027-035-232015-
/O.CON.KPHI.SV.W.0311.000000T0000Z-210923T2015Z/
Hunterdon NJ-Morris NJ-Somerset NJ-Middlesex NJ-
335 PM EDT Thu Sep 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR NORTHEASTERN HUNTERDON...SOUTHERN MORRIS...SOMERSET AND
NORTHWESTERN MIDDLESEX COUNTIES...

At 334 PM EDT, a severe thunderstorm was located over Belle Mead, or
near Somerville, moving north at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Somerville, Somerset, Bridgewater, Madison, Middlesex, Bound Brook,
Manville, Chatham, Mendham, Peapack And Gladstone, Chester, Far
Hills, Rocky Hill, Millstone, Skillman, Flagtown, Kingston, Belle
Mead, Martinsville and Millington.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 24 and 42.
 Interstate 287 in New Jersey between mile markers 9 and 34.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4073 7437 4067 7446 4066 7445 4067 7443
      4066 7442 4036 7459 4037 7462 4039 7463
      4039 7467 4042 7475 4043 7479 4081 7477
      4075 7436
TIME...MOT...LOC 1934Z 194DEG 31KT 4049 7466 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann

498 
WWUS51 KPHI 231944
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
344 PM EDT Thu Sep 23 2021

NJC019-231954-
/O.CAN.KPHI.SV.W.0311.000000T0000Z-210923T2015Z/
Hunterdon NJ-
344 PM EDT Thu Sep 23 2021

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

LAT...LON 4075 7436 4067 7446 4066 7445 4066 7443
      4061 7445 4036 7459 4039 7463 4039 7467
      4056 7473 4062 7471 4064 7473 4070 7472
      4074 7476 4081 7477
TIME...MOT...LOC 1944Z 194DEG 34KT 4063 7461 

$$

NJC023-027-035-232015-
/O.CON.KPHI.SV.W.0311.000000T0000Z-210923T2015Z/
Morris NJ-Somerset NJ-Middlesex NJ-
344 PM EDT Thu Sep 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR SOUTHERN MORRIS...SOMERSET AND NORTHWESTERN MIDDLESEX COUNTIES...

At 344 PM EDT, a severe thunderstorm was located near Bridgewater, or
near Somerville, moving north at 40 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Somerville, Somerset, Bridgewater, Madison, Middlesex, Bound Brook,
Manville, Chatham, Mendham, Peapack And Gladstone, Chester, Far
Hills, Rocky Hill, Millstone, Flagtown, Kingston, Belle Mead,
Martinsville, Millington and Kendall Park.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 27 and 42.
 Interstate 287 in New Jersey between mile markers 9 and 34.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4075 7436 4067 7446 4066 7445 4066 7443
      4061 7445 4036 7459 4039 7463 4039 7467
      4056 7473 4062 7471 4064 7473 4070 7472
      4074 7476 4081 7477
TIME...MOT...LOC 1944Z 194DEG 34KT 4063 7461 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann

232 
WWUS51 KPHI 231957
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
357 PM EDT Thu Sep 23 2021

NJC023-027-035-232015-
/O.CON.KPHI.SV.W.0311.000000T0000Z-210923T2015Z/
Morris NJ-Somerset NJ-Middlesex NJ-
357 PM EDT Thu Sep 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR SOUTHEASTERN MORRIS...NORTHEASTERN SOMERSET AND NORTH CENTRAL
MIDDLESEX COUNTIES...

At 357 PM EDT, a severe thunderstorm was located over Mendham, or
near Morristown, moving north at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Somerville, Bridgewater, Madison, Middlesex, Bound Brook, Manville,
Chatham, Mendham, Peapack And Gladstone, Chester, Far Hills,
Millstone, Martinsville, Millington, Basking Ridge, Bernardsville,
Dunellen, Raritan, Watchung and South Bound Brook.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 29 and 42.
 Interstate 287 in New Jersey between mile markers 10 and 33.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4071 7441 4069 7444 4067 7446 4066 7445
      4066 7443 4060 7446 4059 7446 4048 7456
      4053 7464 4064 7469 4080 7470 4079 7465
      4075 7437 4074 7437
TIME...MOT...LOC 1957Z 194DEG 31KT 4074 7457 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann

963 
WWUS51 KPHI 232007
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
407 PM EDT Thu Sep 23 2021

NJC023-027-035-232016-
/O.EXP.KPHI.SV.W.0311.000000T0000Z-210923T2015Z/
Morris NJ-Somerset NJ-Middlesex NJ-
407 PM EDT Thu Sep 23 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MORRIS...
NORTHEASTERN SOMERSET AND NORTH CENTRAL MIDDLESEX COUNTIES WILL
EXPIRE AT 415 PM EDT...
        
The storm which prompted the warning has weakened below severe 
limits and is exiting the warned area. Therefore, the warning will 
be allowed to expire.  However gusty winds and heavy rain are still 
possible with this thunderstorm.

LAT...LON 4071 7441 4069 7444 4067 7446 4066 7445
      4066 7443 4060 7446 4059 7446 4048 7456
      4053 7464 4064 7469 4080 7470 4079 7465
      4075 7437 4074 7437
TIME...MOT...LOC 2006Z 194DEG 31KT 4082 7455 

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 22, 8:43 PM EDT	Gale Warning	PHI		18 hr
Sep 23, 9:12 AM EDT	Coastal Flood Advisory	PHI	Burlington, Camden, Gloucester	10 hr
Sep 23, 11:33 AM EDT	Areal Flood Advisory	PHI	Cumberland, Gloucester, Salem	3 hr
Sep 23, 11:57 AM EDT	Flash Flood Warning	PHI	Gloucester, Salem	3 hr
Sep 23, 12:12 PM EDT	Severe Thunderstorm Warning	PHI	Gloucester, Salem	48 min
Sep 23, 12:54 PM EDT	Special Weather Statement	PHI	Gloucester	51 min
Sep 23, 12:56 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Hunterdon, Mercer, Warren	3 hr
Sep 23, 1:13 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Salem	47 min
Sep 23, 1:42 PM EDT	Flash Flood Warning	PHI	Burlington, Camden, Gloucester	4 hr
Sep 23, 1:58 PM EDT	Special Weather Statement	PHI	Camden, Hunterdon	32 min
Sep 23, 2:37 PM EDT	Areal Flood Advisory	PHI	Burlington, Hunterdon, Mercer, Middlesex, Monmouth, Morris and 3 more	3 hr
Sep 23, 2:47 PM EDT	Special Weather Statement	PHI	Hunterdon, Mercer	28 min
Sep 23, 2:52 PM EDT	Special Weather Statement	PHI	Camden	23 min
Sep 23, 3:13 PM EDT	Special Weather Statement	PHI	Mercer, Somerset	32 min
Sep 23, 3:16 PM EDT	Special Weather Statement	PHI	Burlington	29 min
Sep 23, 3:26 PM EDT	Flash Flood Warning	PHI	Burlington, Hunterdon, Mercer, Middlesex, Morris, Somerset	2 hr
Sep 23, 3:50 PM EDT	Special Weather Statement	PHI	Burlington	25 min
Sep 23, 4:21 PM EDT	Areal Flood Advisory	PHI	Middlesex, Monmouth, Morris, Ocean, Somerset, Sussex	15 min
Sep 23, 4:36 PM EDT	Flash Flood Warning	PHI	Middlesex, Monmouth, Morris, Somerset, Sussex	3 hr
Sep 23, 5:00 PM EDT	Special Weather Statement	PHI	Monmouth	30 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2021 Every 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.