Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 324, NWS Philadelphia/Mount Holly

December 11, 20217 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Dec 11, 2021, 9:21 PM EST for 7 counties in New Jersey. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Dec 11, 2021, 9:21 PM EST (02:21 UTC)
Expired
Dec 11, 2021, 9:50 PM EST
In force
29 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

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

The radar

The Philadelphia radar (KDIX), 96 km from the middle of the area, began a volume at 02:21 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 2.4 hours before the alert went out and 147 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 2021-12-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2021-12-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 428 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
537 m above ground
0-6 km bulk shear
78 kt
0-1 km storm-relative helicity
428 m²/s²
0-3 km storm-relative helicity
485 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

395 
WUUS51 KPHI 120221
SVRPHI
NJC019-021-023-027-035-037-041-120315-
/O.NEW.KPHI.SV.W.0324.211212T0221Z-211212T0315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
921 PM EST Sat Dec 11 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 1015 PM EST.

* At 920 PM EST, severe thunderstorms were located along a line
  extending from near Chester to near White House Station, moving
  east at 60 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Morristown, Somerville, Newton, Bridgewater, Dover, Madison,
  Hopatcong, Middlesex, Florham Park, East Hanover, Lincoln Park,
  Bound Brook, Manville, Kinnelon, Hackettstown, Chatham, Byram,
  Boonton, Butler and Wharton.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 2 and 42.
 Interstate 80 in New Jersey between mile markers 11 and 47.
 Interstate 287 in New Jersey between mile markers 9 and 54.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 4120 7436 4110 7449 4104 7450 4100 7430
      4090 7427 4091 7434 4075 7436 4067 7446
      4066 7445 4066 7442 4053 7450 4028 7486
      4040 7497 4042 7506 4054 7507 4060 7520
      4087 7503 4134 7464
TIME...MOT...LOC 0220Z 259DEG 53KT 4131 7429 4058 7483 

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

$$

Davis
2 follow-up statements
790 
WWUS51 KPHI 120244
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
944 PM EST Sat Dec 11 2021

NJC037-041-120253-
/O.CAN.KPHI.SV.W.0324.000000T0000Z-211212T0315Z/
Sussex NJ-Warren NJ-
944 PM EST Sat Dec 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR SUSSEX AND WARREN COUNTIES IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 4100 7430 4090 7427 4091 7434 4075 7436
      4067 7446 4066 7445 4066 7442 4053 7450
      4028 7486 4040 7497 4042 7506 4070 7473
      4103 7447
TIME...MOT...LOC 0243Z 259DEG 53KT 4137 7387 4064 7441 

$$

NJC019-021-023-027-035-120315-
/O.CON.KPHI.SV.W.0324.000000T0000Z-211212T0315Z/
Morris NJ-Hunterdon NJ-Mercer NJ-Somerset NJ-Middlesex NJ-
944 PM EST Sat Dec 11 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM EST
FOR EASTERN MORRIS...SOUTHEASTERN HUNTERDON...NORTHWESTERN MERCER...
SOMERSET AND NORTH CENTRAL MIDDLESEX COUNTIES...

At 943 PM EST, severe thunderstorms were located along a line
extending from near Cold Spring to Plainfield, moving east at 60 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Morristown, Somerville, Bridgewater, Dover, Madison, Middlesex,
Florham Park, East Hanover, Lincoln Park, Bound Brook, Manville,
Kinnelon, Chatham, Boonton, Butler, Wharton, Rockaway, Morris Plains,
Mendham and Flemington.

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 24 and 42.
 Interstate 80 in New Jersey between mile markers 35 and 47.
 Interstate 287 in New Jersey between mile markers 9 and 54.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.

&&

LAT...LON 4100 7430 4090 7427 4091 7434 4075 7436
      4067 7446 4066 7445 4066 7442 4053 7450
      4028 7486 4040 7497 4042 7506 4070 7473
      4103 7447
TIME...MOT...LOC 0243Z 259DEG 53KT 4137 7387 4064 7441 

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

$$

Davis
032 
WWUS51 KPHI 120250
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
950 PM EST Sat Dec 11 2021

NJC019-021-023-027-035-120300-
/O.CAN.KPHI.SV.W.0324.000000T0000Z-211212T0315Z/
Morris NJ-Hunterdon NJ-Mercer NJ-Somerset NJ-Middlesex NJ-
950 PM EST Sat Dec 11 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN MORRIS...SOUTHEASTERN
HUNTERDON...NORTHWESTERN MERCER...SOMERSET AND NORTH CENTRAL
MIDDLESEX COUNTIES IS CANCELLED...
    
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been cancelled. However gusty winds are 
still possible with these thunderstorms.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 4100 7430 4090 7427 4091 7434 4075 7436
      4067 7446 4066 7445 4066 7442 4053 7450
      4028 7486 4040 7497 4042 7506 4070 7473
      4103 7447
TIME...MOT...LOC 0247Z 259DEG 53KT 4138 7378 4065 7432 

$$

Davis

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 12, 3:32 AM ESTSmall Craft AdvisoryPHI18 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.