Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 258, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 12, 2021, 4:11 PM EDT for Morris County, Sussex County, Warren County, New Jersey. It was in force for 34 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
- Aug 12, 2021, 4:11 PM EDT (20:11 UTC)
- Expired
- Aug 12, 2021, 4:45 PM EDT
- In force
- 34 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Morris County, NJ, Sussex County, NJ, Warren County, NJ
The radar
The Philadelphia radar (KDIX), 108 km from the middle of the area, began a volume at 20:14 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 |
|---|---|---|---|
| Aug 12, 4:40 PM EDT | TSTM WND DMG | Mendham, NJ | TREE DOWN BLOCKING A ROAD. TIME ESTIMATED FROM 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, 8.2 hours before the alert went out and 136 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.
- Mixed-layer CAPE
- 278 J/kg
- Mixed-layer CIN
- -162 J/kg
- Mixed-layer LCL
- 1400 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- -82 m²/s²
- 0-3 km storm-relative helicity
- -47 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
338
WUUS51 KPHI 122011
SVRPHI
NJC027-037-041-122045-
/O.NEW.KPHI.SV.W.0258.210812T2011Z-210812T2045Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
411 PM EDT Thu Aug 12 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Morris County in northern New Jersey...
Southeastern Sussex County in northwestern New Jersey...
East central Warren County in northwestern New Jersey...
* Until 445 PM EDT.
* At 411 PM EDT, severe thunderstorms were located along a line
extending from near Pellettown to Lake Mohawk to Allamuchy-Panther
Valley, moving east at 50 mph.
HAZARD...60 mph wind gusts.
SOURCE...Law enforcement. Theses storms have a history of
producing downed trees and power lines.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Morristown, Dover, Madison, Hopatcong, Florham Park, East Hanover,
Lincoln Park, Kinnelon, Hackettstown, Chatham, Boonton, Butler,
Wharton, Rockaway, Morris Plains, Mount Arlington, Mendham,
Mountain Lakes, Stanhope and Riverdale.
This includes the following highways...
Interstate 80 in New Jersey between mile markers 23 and 48.
Interstate 287 in New Jersey between mile markers 31 and 54.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Wind damage with these storms will occur before any rain or
lightning. Do not wait for the sound of thunder before taking cover.
SEEK SHELTER IMMEDIATELY inside a sturdy structure and stay away from
windows.
&&
LAT...LON 4091 7434 4083 7433 4072 7439 4074 7455
4076 7456 4074 7461 4079 7489 4086 7486
4097 7468 4110 7453 4110 7449 4104 7450
4105 7445 4102 7443 4103 7442 4100 7430
4097 7428 4092 7429 4090 7427
TIME...MOT...LOC 2011Z 285DEG 45KT 4113 7466 4104 7466 4093 7484
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...OBSERVED
MAX WIND GUST...60 MPH
$$
JEO1 follow-up statement
174
WWUS51 KPHI 122045
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
445 PM EDT Thu Aug 12 2021
NJC027-037-041-122055-
/O.EXP.KPHI.SV.W.0258.000000T0000Z-210812T2045Z/
Morris NJ-Sussex NJ-Warren NJ-
445 PM EDT Thu Aug 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR MORRIS...SOUTHEASTERN SUSSEX
AND EAST CENTRAL WARREN COUNTIES HAS EXPIRED...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning has been allowed to expire. However gusty
winds are still possible with these thunderstorms.
LAT...LON 4091 7434 4083 7433 4072 7439 4074 7455
4076 7456 4074 7461 4079 7489 4086 7486
4097 7468 4110 7453 4110 7449 4104 7450
4105 7445 4102 7443 4103 7442 4100 7430
4097 7428 4092 7429 4090 7427
TIME...MOT...LOC 2045Z 285DEG 45KT 4113 7466 4104 7466 4093 7484
$$
JEOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 11, 8:10 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Sussex, Warren | 35 min |
| Aug 11, 10:54 PM EDT | Areal Flood Warning | PHI | Morris, Warren | 3 hr |
| Aug 12, 3:33 PM EDT | Severe Thunderstorm Warning | PHI | Sussex, Warren | 57 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.