Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 14, NWS Philadelphia/Mount Holly

April 21, 20214 counties in New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 21, 2021, 1:43 PM EDT for 4 counties in New Jersey. It was in force for 33 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: Apr 21, 2021, 1:43 PM EDT (17:43 UTC)
Expired: Apr 21, 2021, 2:16 PM EDT
In force: 33 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Philadelphia radar (KDIX), 97 km from the middle of the area, began a volume at 17:43 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
Apr 21, 1:48 PM EDT	TSTM WND DMG	3 N Branchburg Twp, NJ	UTILITY POLE DOWN ON US-22 EASTBOUND WEST OF READINGTON RD. ALL LANES WERE CLOSED. TIME ESTIMATED FROM RADAR.
Apr 21, 1:55 PM EDT	TSTM WND DMG	3 Sse Far Hills, NJ	A FEW MEDIUM SIZED TREE BRANCHES DOWN. TIME ESTIMATED FROM RADAR.
Apr 21, 1:55 PM EDT	HAIL 0.25	Morris Twp, NJ
Apr 21, 1:56 PM EDT	HAIL 0.25	1 Ese Whippany, NJ	PEA SIZE HAIL REPORTED IN WHIPPANY, NJ. TIME ESTIMATED FROM RADAR.

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.

Issued	Product	Office	Lasted
Apr 21, 12:28 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 5.7 hours before the alert went out and 131 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1427 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 206 m²/s²
0-3 km storm-relative helicity: 201 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

123 
WUUS51 KPHI 211743
SVRPHI
NJC019-023-027-035-211845-
/O.NEW.KPHI.SV.W.0014.210421T1743Z-210421T1845Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
143 PM EDT Wed Apr 21 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Hunterdon County in northwestern New Jersey...
  Morris County in northern New Jersey...
  Somerset County in northern New Jersey...
  Northwestern Middlesex County in northern New Jersey...

* Until 245 PM EDT.

* At 143 PM EDT, severe thunderstorms were located along a line
  extending from near Netcong to near Hopewell, moving east at 30
  mph.

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

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  New Brunswick, Morristown, Somerville, Somerset, East Brunswick,
  Bridgewater, North Brunswick, Dover, Madison, Middlesex, Florham
  Park, East Hanover, Lincoln Park, Bound Brook, Manville, Kinnelon,
  Chatham, Boonton, Butler and Wharton.

People at the Morris County Mega Site should seek safe shelter
immediately!

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 24 and 42.
 Interstate 80 in New Jersey between mile markers 30 and 49.
 Interstate 287 in New Jersey between mile markers 3 and 52.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4090 7427 4091 7434 4086 7432 4079 7437
      4075 7436 4067 7446 4066 7445 4066 7440
      4060 7446 4060 7436 4043 7443 4043 7489
      4101 7460 4108 7450 4104 7450 4105 7445
      4102 7443 4100 7433 4096 7428
TIME...MOT...LOC 1743Z 272DEG 25KT 4089 7466 4041 7484 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Davis

2 follow-up statements

496 
WWUS51 KPHI 211806
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
206 PM EDT Wed Apr 21 2021

NJC019-023-211816-
/O.CAN.KPHI.SV.W.0014.000000T0000Z-210421T1845Z/
Hunterdon NJ-Middlesex NJ-
206 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN HUNTERDON AND
NORTHWESTERN MIDDLESEX COUNTIES IS CANCELLED...

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

A Severe Thunderstorm Watch remains in effect until 600 PM EDT for
northern New Jersey.

LAT...LON 4090 7427 4091 7434 4086 7432 4079 7437
      4075 7436 4067 7446 4066 7445 4066 7440
      4060 7446 4059 7460 4102 7457 4104 7450
      4105 7445 4102 7443 4100 7433 4096 7428
TIME...MOT...LOC 1806Z 272DEG 25KT 4088 7447 4040 7465 

$$

NJC027-035-211845-
/O.CON.KPHI.SV.W.0014.000000T0000Z-210421T1845Z/
Morris NJ-Somerset NJ-
206 PM EDT Wed Apr 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR EASTERN MORRIS AND NORTHEASTERN SOMERSET COUNTIES...

At 206 PM EDT, severe thunderstorms were located along a line
extending from Mountain Lakes to Rocky Hill, moving east at 30 mph.

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

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Morristown, Dover, Madison, Florham Park, East Hanover, Lincoln Park,
Kinnelon, Chatham, Boonton, Butler, Wharton, Rockaway, Morris Plains,
Mendham, Mountain Lakes, Victory Gardens, Green Pond, Martinsville,
Millington and Parsippany.

People at the Morris County Mega Site should seek safe shelter
immediately!

This includes the following highways...
 Interstate 78 in New Jersey between mile markers 34 and 42.
 Interstate 80 in New Jersey between mile markers 34 and 49.
 Interstate 287 in New Jersey between mile markers 26 and 52.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4090 7427 4091 7434 4086 7432 4079 7437
      4075 7436 4067 7446 4066 7445 4066 7440
      4060 7446 4059 7460 4102 7457 4104 7450
      4105 7445 4102 7443 4100 7433 4096 7428
TIME...MOT...LOC 1806Z 272DEG 25KT 4088 7447 4040 7465 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Davis

432 
WWUS51 KPHI 211816
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
216 PM EDT Wed Apr 21 2021

NJC027-035-211825-
/O.CAN.KPHI.SV.W.0014.000000T0000Z-210421T1845Z/
Morris NJ-Somerset NJ-
216 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN MORRIS AND
NORTHEASTERN SOMERSET 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.

A Severe Thunderstorm Watch remains in effect until 600 PM EDT for
northern New Jersey.

LAT...LON 4090 7427 4091 7434 4086 7432 4079 7437
      4075 7436 4067 7446 4066 7445 4066 7440
      4060 7446 4059 7460 4102 7457 4104 7450
      4105 7445 4102 7443 4100 7433 4096 7428
TIME...MOT...LOC 1814Z 272DEG 25KT 4088 7439 4040 7457 

$$

Davis

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 20, 8:48 PM EDT	Freeze Watch	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	7 hr
Apr 21, 3:26 AM EDT	Freeze Warning	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	30 hr
Apr 21, 12:25 PM EDT	Severe Thunderstorm Warning	PHI	Warren	50 min
Apr 21, 12:51 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	21 min
Apr 21, 12:55 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	27 min
Apr 21, 1:10 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Gloucester, Mercer, Salem	50 min
Apr 21, 1:17 PM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset, Sussex	58 min
Apr 21, 1:28 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester	36 min
Apr 21, 1:30 PM EDT	Special Marine Warning	PHI		60 min
Apr 21, 1:58 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Monmouth, Ocean	62 min
Apr 21, 2:02 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Monmouth, Ocean	43 min
Apr 21, 2:03 PM EDT	Special Weather Statement	PHI	Cumberland	27 min
Apr 21, 2:17 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cumberland, Gloucester, Salem	43 min
Apr 21, 2:28 PM EDT	Special Weather Statement	PHI	Middlesex, Monmouth	47 min
Apr 21, 2:30 PM EDT	Special Marine Warning	PHI		60 min
Apr 21, 2:38 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	37 min
Apr 21, 2:40 PM EDT	Special Marine Warning	PHI		55 min
Apr 21, 2:43 PM EDT	Special Weather Statement	PHI	Cape May	32 min
Apr 21, 2:50 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	40 min
Apr 21, 3:02 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic	28 min
Apr 21, 3:07 PM EDT	Special Marine Warning	PHI		53 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.