Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 171, NWS Philadelphia/Mount Holly

July 12, 2021Morris County, Sussex County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 12, 2021, 5:57 PM EDT for Morris County, Sussex County, New Jersey. It was in force for 63 min. 1 report 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: Jul 12, 2021, 5:57 PM EDT (21:57 UTC)
Expired: Jul 12, 2021, 7:00 PM EDT
In force: 63 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Morris County, NJ, Sussex County, NJ

The radar

The Philadelphia radar (KDIX), 122 km from the middle of the area, began a volume at 21:59 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
Jul 12, 6:17 PM EDT	TSTM WND DMG	2 Ne Green Pond, NJ	DOWNED TREES AND WIRES NEAR GREEN POND ROAD. 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
Jul 12, 3:34 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.0 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-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: 857 J/kg
Mixed-layer CIN: -57 J/kg
Mixed-layer LCL: 697 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 85 m²/s²
0-3 km storm-relative helicity: 114 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

935 
WUUS51 KPHI 122157
SVRPHI
NJC027-037-122300-
/O.NEW.KPHI.SV.W.0171.210712T2157Z-210712T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
557 PM EDT Mon Jul 12 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northeastern Morris County in northern New Jersey...
  East central Sussex County in northwestern New Jersey...

* Until 700 PM EDT.

* At 557 PM EDT, severe thunderstorms were located along a line
  extending from West Milford to near Green Pond, moving east at 15
  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...
  Lincoln Park, Kinnelon, Boonton, Butler, Riverdale, Green Pond,
  Pequannock Township, Lake Telemark and Highland Lake.

This includes the following highways...
 Interstate 80 in New Jersey between mile markers 47 and 48.
 Interstate 287 in New Jersey between mile markers 45 and 54.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 4120 7436 4109 7450 4107 7449 4104 7450
      4105 7445 4102 7443 4103 7442 4100 7430
      4097 7428 4092 7429 4090 7427 4091 7434
      4083 7433 4105 7461 4122 7439 4121 7439
TIME...MOT...LOC 2157Z 280DEG 12KT 4113 7439 4106 7451 

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

Staarmann

2 follow-up statements

539 
WWUS51 KPHI 122217
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
617 PM EDT Mon Jul 12 2021

NJC027-037-122300-
/O.CON.KPHI.SV.W.0171.000000T0000Z-210712T2300Z/
Morris NJ-Sussex NJ-
617 PM EDT Mon Jul 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM EDT
FOR NORTHEASTERN MORRIS AND EAST CENTRAL SUSSEX COUNTIES...

At 616 PM EDT, severe thunderstorms were located along a line
extending from Ringwood to near Green Pond, moving east at 15 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...
Lincoln Park, Kinnelon, Boonton, Butler, Riverdale, Green Pond,
Pequannock Township and Lake Telemark.

This includes the following highways...
 Interstate 80 in New Jersey between mile markers 47 and 48.
 Interstate 287 in New Jersey between mile markers 45 and 54.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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

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

&&

LAT...LON 4114 7444 4109 7450 4107 7449 4104 7450
      4105 7445 4102 7443 4103 7442 4100 7430
      4097 7428 4092 7429 4090 7427 4091 7434
      4083 7433 4105 7461 4111 7453
TIME...MOT...LOC 2216Z 282DEG 11KT 4110 7430 4106 7451 

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

Staarmann

884 
WWUS51 KPHI 122246
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
646 PM EDT Mon Jul 12 2021

NJC027-037-122300-
/O.CON.KPHI.SV.W.0171.000000T0000Z-210712T2300Z/
Morris NJ-Sussex NJ-
646 PM EDT Mon Jul 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 PM EDT
FOR NORTHEASTERN MORRIS AND EAST CENTRAL SUSSEX COUNTIES...

At 646 PM EDT, severe thunderstorms were located along a line
extending from Bloomingdale to near Ogdensburg, moving southeast at 5
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...
Lincoln Park, Kinnelon, Boonton, Butler, Riverdale, Green Pond,
Pequannock Township and Lake Telemark.

This includes the following highways...
 Interstate 80 in New Jersey between mile markers 47 and 48.
 Interstate 287 in New Jersey between mile markers 45 and 54.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

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

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

&&

LAT...LON 4114 7444 4109 7450 4107 7449 4104 7450
      4105 7445 4102 7443 4103 7442 4100 7430
      4097 7428 4092 7429 4090 7427 4091 7434
      4083 7433 4105 7461 4111 7453
TIME...MOT...LOC 2246Z 298DEG 6KT 4105 7433 4104 7458 

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

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 1:59 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden	3 hr
Jul 12, 2:12 PM EDT	Flash Flood Warning Emergency	PHI	Burlington	7 hr
Jul 12, 2:20 PM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth	3 hr
Jul 12, 2:37 PM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Monmouth	93 min
Jul 12, 3:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	67 min
Jul 12, 3:31 PM EDT	Severe Thunderstorm Warning	PHI	Middlesex, Monmouth	41 min
Jul 12, 4:26 PM EDT	Special Marine Warning	PHI		2 hr
Jul 12, 4:33 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	42 min
Jul 12, 4:52 PM EDT	Areal Flood Advisory	PHI	Monmouth, Ocean	98 min
Jul 12, 5:08 PM EDT	Areal Flood Advisory	PHI	Sussex	5 hr
Jul 12, 5:08 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Mercer	67 min
Jul 12, 5:26 PM EDT	Areal Flood Advisory	PHI	Camden	2 hr
Jul 12, 5:36 PM EDT	Special Weather Statement	PHI	Sussex	24 min
Jul 12, 5:41 PM EDT	Areal Flood Advisory	PHI	Burlington	83 min
Jul 12, 6:01 PM EDT	Flash Flood Warning	PHI	Camden	102 min
Jul 12, 6:08 PM EDT	Areal Flood Advisory	PHI	Morris	98 min
Jul 12, 6:43 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester	93 min
Jul 12, 6:52 PM EDT	Severe Thunderstorm Warning	PHI	Morris, Sussex	34 min
Jul 12, 7:00 PM EDT	Areal Flood Advisory	PHI	Gloucester, Salem	112 min
Jul 12, 7:06 PM EDT	Severe Thunderstorm Warning	PHI	Salem	69 min
Jul 12, 7:11 PM EDT	Flash Flood Warning	PHI	Morris, Sussex	35 min
Jul 12, 7:33 PM EDT	Special Marine Warning	PHI		58 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.