Alert archive / New Jersey / Severe Thunderstorm Warnings in 2020
Severe Thunderstorm Warning 243, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 18, 2020, 1:38 AM EDT for 6 counties in New Jersey; Bucks County, Northampton County, Pennsylvania. It was in force for 37 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
- Aug 18, 2020, 1:38 AM EDT (05:38 UTC)
- Expired
- Aug 18, 2020, 2:15 AM EDT
- In force
- 37 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, Middlesex County, NJ, Morris County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Bucks County, PA, Northampton County, PA
The radar
The Philadelphia radar (KDIX), 104 km from the middle of the area, began a volume at 05:39 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 18, 1:41 AM EDT | TSTM WND DMG | 2 S Schooleys Mountain, NJ | TREES AND WIRES DOWN IN WASHINGTON TWP. TIME ESTIMATED BY RADAR. |
| Aug 18, 1:47 AM EDT | TSTM WND DMG | 3 Wsw Jefferson Twp, NJ | DOWNED TREES AND WIRES NEAR WINONA TRAIL IN WOODPORT. TIME ESTIMATED FROM RADAR. |
| Aug 18, 1:53 AM EDT | TSTM WND DMG | Schooleys Mountain, NJ | DOWNED POWER LINES NEAR ROUTE 24 IN SCHOOLEYS MOUNTAIN. 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 00:00Z, 5.6 hours before the alert went out and 139 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
- 116 J/kg
- Mixed-layer CIN
- -68 J/kg
- Mixed-layer LCL
- 878 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 88 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
695
WUUS51 KPHI 180538
SVRPHI
NJC019-023-027-035-037-041-PAC017-095-180615-
/O.NEW.KPHI.SV.W.0243.200818T0538Z-200818T0615Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
138 AM EDT Tue Aug 18 2020
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...
Central Sussex County in northwestern New Jersey...
Warren County in northwestern New Jersey...
Somerset County in northern New Jersey...
North central Middlesex County in northern New Jersey...
Northwestern Bucks County in southeastern Pennsylvania...
Southeastern Northampton County in eastern Pennsylvania...
* Until 215 AM EDT.
* At 137 AM EDT, severe thunderstorms were located along a line
extending from Branchville to Beatyestown to Ferndale, moving east
at 30 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Easton, Morristown, Somerville, Newton, Bridgewater, Dover,
Madison, Hopatcong, Middlesex, Florham Park, East Hanover, Lincoln
Park, Bound Brook, Manville, Kinnelon, Hackettstown, Chatham,
Boonton, Butler and Wharton.
This includes the following highways...
Interstate 78 in Pennsylvania between mile markers 75 and 76.
Interstate 78 in New Jersey between mile markers 0 and 42.
Interstate 80 in New Jersey between mile markers 10 and 48.
Interstate 287 in New Jersey between mile markers 8 and 54.
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.
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.
Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.
Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4120 7437 4110 7449 4104 7450 4105 7445
4102 7443 4100 7430 4090 7427 4091 7433
4083 7433 4079 7437 4074 7437 4067 7446
4065 7440 4060 7442 4056 7447 4041 7471
4051 7537 4087 7505 4113 7486 4124 7443
TIME...MOT...LOC 0537Z 281DEG 24KT 4113 7477 4083 7483 4052 7518
TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
$$
Robertson2 follow-up statements
932
WWUS51 KPHI 180557
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
157 AM EDT Tue Aug 18 2020
PAC017-095-180605-
/O.CAN.KPHI.SV.W.0243.000000T0000Z-200818T0615Z/
Bucks PA-Northampton PA-
157 AM EDT Tue Aug 18 2020
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN BUCKS AND
SOUTHEASTERN NORTHAMPTON COUNTIES IS CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled. Additional showers
and thunderstorms remain possible.
LAT...LON 4120 7437 4110 7449 4104 7450 4105 7445
4102 7443 4100 7430 4090 7427 4091 7433
4083 7433 4079 7437 4074 7437 4067 7446
4065 7440 4060 7442 4056 7447 4051 7455
4059 7504 4091 7487 4112 7472 4124 7443
TIME...MOT...LOC 0555Z 268DEG 34KT 4111 7446 4085 7457 4059 7494
$$
NJC019-023-027-035-037-041-180615-
/O.CON.KPHI.SV.W.0243.000000T0000Z-200818T0615Z/
Morris NJ-Hunterdon NJ-Sussex NJ-Warren NJ-Somerset NJ-Middlesex NJ-
157 AM EDT Tue Aug 18 2020
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 AM EDT
FOR MORRIS...NORTHEASTERN HUNTERDON...SOUTHEASTERN SUSSEX...EAST
CENTRAL WARREN...NORTHERN SOMERSET AND NORTH CENTRAL MIDDLESEX
COUNTIES...
At 155 AM EDT, severe thunderstorms were located along a line
extending from near West Milford to near Victory Gardens to near
Clinton, moving east 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...
Morristown, Somerville, Newton, Bridgewater, Dover, Madison,
Hopatcong, Middlesex, Florham Park, East Hanover, Lincoln Park, Bound
Brook, Manville, Kinnelon, Hackettstown, Chatham, Boonton, Butler,
Wharton and Rockaway.
This includes the following highways...
Interstate 78 in New Jersey between mile markers 12 and 42.
Interstate 80 in New Jersey between mile markers 18 and 48.
Interstate 287 in New Jersey between mile markers 8 and 54.
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.
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 4120 7437 4110 7449 4104 7450 4105 7445
4102 7443 4100 7430 4090 7427 4091 7433
4083 7433 4079 7437 4074 7437 4067 7446
4065 7440 4060 7442 4056 7447 4051 7455
4059 7504 4091 7487 4112 7472 4124 7443
TIME...MOT...LOC 0555Z 268DEG 34KT 4111 7446 4085 7457 4059 7494
TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
$$
Robertson009
WWUS51 KPHI 180609
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
209 AM EDT Tue Aug 18 2020
NJC019-023-027-035-037-041-180617-
/O.EXP.KPHI.SV.W.0243.000000T0000Z-200818T0615Z/
Morris NJ-Hunterdon NJ-Sussex NJ-Warren NJ-Somerset NJ-Middlesex NJ-
209 AM EDT Tue Aug 18 2020
...THE SEVERE THUNDERSTORM WARNING FOR MORRIS...NORTHEASTERN
HUNTERDON...SOUTHEASTERN SUSSEX...EAST CENTRAL WARREN...NORTHERN
SOMERSET AND NORTH CENTRAL MIDDLESEX COUNTIES WILL EXPIRE AT 215 AM
EDT...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire. However small
hail, gusty winds and heavy rain are still possible with these
thunderstorms.
LAT...LON 4120 7437 4110 7449 4104 7450 4105 7445
4102 7443 4100 7430 4090 7427 4091 7433
4083 7433 4079 7437 4074 7437 4067 7446
4065 7440 4060 7442 4056 7447 4051 7455
4059 7504 4091 7487 4112 7472 4124 7443
TIME...MOT...LOC 0607Z 281DEG 24KT 4110 7436 4084 7447 4058 7484
$$
RobertsonThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 11:51 PM EDT | Coastal Flood Statement | PHI | Ocean | 4 hr |
| Aug 18, 12:31 AM EDT | Tornado Warning | PHI | Warren | 29 min |
| Aug 18, 12:39 AM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Sussex, Warren | 66 min |
| Aug 18, 12:58 AM EDT | Special Weather Statement | PHI | Hunterdon | 47 min |
| Aug 18, 1:13 AM EDT | Areal Flood Advisory | PHI | Hunterdon, Middlesex, Morris, Somerset, Sussex, Warren | 2 hr |
| Aug 18, 2:15 AM EDT | Special Weather Statement | PHI | Hunterdon, Morris, Somerset | 30 min |
| Aug 17, 11:26 PM EDT | Special Weather Statement | PHI | Monroe | 49 min |
| Aug 17, 11:59 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Monroe | 46 min |
Nearby
Severe Thunderstorm Warnings in New Jersey, 2020Severe Thunderstorm Warnings in Pennsylvania, 2020Every severe thunderstorm warning in 2020
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.