Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 187, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2021, 6:02 PM EDT for Bucks County, Pennsylvania; Hunterdon County, Mercer County, Somerset County, New Jersey. It was in force for 43 min. 2 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
- Jul 17, 2021, 6:02 PM EDT (22:02 UTC)
- Expired
- Jul 17, 2021, 6:45 PM EDT
- In force
- 43 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
Counties Hunterdon County, NJ, Mercer County, NJ, Somerset County, NJ, Bucks County, PA
The radar
The Philadelphia radar (KDIX), 70 km from the middle of the area, began a volume at 22:01 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 17, 6:15 PM EDT | TSTM WND DMG | Lebanon, NJ | TREE AND WIRES DOWN. TIME ESTIMATED FROM RADAR. |
| Jul 17, 6:43 PM EDT | HAIL 1 | 2 Ne Lambertville, NJ |
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 17, 1:13 PM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 10.0 hours before the alert went out and 176 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
- 1203 J/kg
- Mixed-layer CIN
- -55 J/kg
- Mixed-layer LCL
- 1054 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 35 m²/s²
- 0-3 km storm-relative helicity
- 46 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 1.0
The text
As transmitted.
653
WUUS51 KPHI 172202
SVRPHI
NJC019-021-035-PAC017-172245-
/O.NEW.KPHI.SV.W.0187.210717T2202Z-210717T2245Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
602 PM EDT Sat Jul 17 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Hunterdon County in northwestern New Jersey...
Northwestern Mercer County in central New Jersey...
Southwestern Somerset County in northern New Jersey...
North central Bucks County in southeastern Pennsylvania...
* Until 645 PM EDT.
* At 601 PM EDT, a severe thunderstorm was located over Flemington,
or 15 miles southwest of Somerville, moving northeast 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...
Somerville, Bridgewater, Byram, Bedminster, Flemington, Tinicum,
High Bridge, Clinton, New Hope, Hopewell, Frenchtown, Lebanon,
Stockton, Skillman, Flagtown, Belle Mead, Lumberville, Ottsville,
Sergeantsville and Pipersville.
This includes the following highways...
Interstate 78 in New Jersey between mile markers 14 and 33.
Interstate 287 in New Jersey between mile markers 17 and 21.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.
&&
LAT...LON 4032 7489 4040 7527 4059 7501 4070 7492
4064 7458 4036 7471 4039 7480
TIME...MOT...LOC 2201Z 205DEG 11KT 4048 7487
HAIL...1.00IN
WIND...60MPH
$$
JEO2 follow-up statements
269
WWUS51 KPHI 172212
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
612 PM EDT Sat Jul 17 2021
NJC019-021-035-PAC017-172245-
/O.CON.KPHI.SV.W.0187.000000T0000Z-210717T2245Z/
Hunterdon NJ-Mercer NJ-Somerset NJ-Bucks PA-
612 PM EDT Sat Jul 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR EASTERN HUNTERDON...NORTHWESTERN MERCER...SOUTHWESTERN SOMERSET
AND CENTRAL BUCKS COUNTIES...
At 611 PM EDT, a severe thunderstorm was located over Flemington, or
13 miles west of Somerville, moving northeast at 15 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Emergency management. This storm has a history of producing
downed trees and power lines.
IMPACT...Minor damage to vehicles is possible. Wind damage to roofs,
siding, trees, and power lines is possible.
Locations impacted include...
Somerville, Bridgewater, Byram, Flemington, High Bridge, Clinton, New
Hope, Hopewell, Lebanon, Stockton, Skillman, Flagtown,
Sergeantsville, Cloverhill, Belle Mead, Annandale, Gardenville, White
House Station, Lumberville and Sand Brook.
This includes the following highways...
Interstate 78 in New Jersey between mile markers 17 and 33.
Interstate 287 in New Jersey between mile markers 17 and 21.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.
&&
LAT...LON 4032 7489 4034 7496 4037 7515 4050 7500
4058 7495 4069 7488 4064 7458 4036 7471
4039 7480
TIME...MOT...LOC 2211Z 205DEG 11KT 4051 7485
HAIL...1.00IN
WIND...60MPH
$$
JEO960
WWUS51 KPHI 172241
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
641 PM EDT Sat Jul 17 2021
NJC019-021-035-PAC017-172249-
/O.EXP.KPHI.SV.W.0187.000000T0000Z-210717T2245Z/
Hunterdon NJ-Mercer NJ-Somerset NJ-Bucks PA-
641 PM EDT Sat Jul 17 2021
...THE SEVERE THUNDERSTORM WARNING FOR EASTERN HUNTERDON...
NORTHWESTERN MERCER...SOUTHWESTERN SOMERSET AND CENTRAL BUCKS
COUNTIES WILL EXPIRE AT 645 PM EDT...
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire. However additonal
storms producing gusty winds and heavy rain are still possible over
the area and a new severe warning has been issued to cover this
threat.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
central, northern and northwestern New Jersey...and southeastern
Pennsylvania.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.
Remember, a Severe Thunderstorm Warning still remains in effect for
Southeastern Hunterdon County, Northwestern Mercer County, Somerset
County, and Northeastern Bucks County
LAT...LON 4032 7489 4034 7496 4037 7515 4050 7500
4058 7495 4069 7488 4064 7458 4036 7471
4039 7480
TIME...MOT...LOC 2239Z 205DEG 11KT 4058 7481
$$
NCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 16, 8:14 PM EDT | Special Weather Statement | PHI | Montgomery | 31 min |
| Jul 16, 8:41 PM EDT | Special Weather Statement | PHI | Bucks | 34 min |
| Jul 16, 9:07 PM EDT | Special Weather Statement | PHI | Lehigh | 23 min |
| Jul 16, 9:29 PM EDT | Special Weather Statement | PHI | Lehigh | 31 min |
| Jul 16, 10:21 PM EDT | Special Weather Statement | PHI | Lehigh | 24 min |
| Jul 17, 12:55 PM EDT | Special Weather Statement | PHI | Bucks | 50 min |
| Jul 17, 1:05 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 40 min |
| Jul 17, 1:31 PM EDT | Areal Flood Advisory | PHI | Bucks | 97 min |
| Jul 17, 2:30 PM EDT | Special Weather Statement | PHI | Berks | 45 min |
| Jul 17, 2:36 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 39 min |
| Jul 17, 3:06 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 39 min |
| Jul 17, 5:13 PM EDT | Areal Flood Advisory | PHI | Bucks, Montgomery, Philadelphia | 4 hr |
| Jul 17, 5:25 PM EDT | Flash Flood Warning | PHI | Bucks | 6 hr |
| Jul 17, 5:30 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 19 min |
| Jul 17, 6:39 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 51 min |
| Jul 17, 6:51 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 39 min |
| Jul 17, 7:01 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 44 min |
| Jul 17, 7:12 PM EDT | Areal Flood Advisory | PHI | Bucks, Philadelphia | 3 hr |
| Jul 17, 7:26 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 49 min |
| Jul 17, 7:36 PM EDT | Special Weather Statement | PHI | Carbon | 54 min |
| Jul 17, 1:50 PM EDT | Special Marine Warning | PHI | 40 min | |
| Jul 17, 1:56 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Morris, Somerset, Warren | 36 min |
| Jul 17, 2:02 PM EDT | Areal Flood Advisory | PHI | Monmouth, Ocean | 92 min |
| Jul 17, 2:56 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex, Somerset | 49 min |
| Jul 17, 3:09 PM EDT | Tornado Warning | PHI | Middlesex | 21 min |
| Jul 17, 3:38 PM EDT | Areal Flood Advisory | PHI | Middlesex | 40 min |
| Jul 17, 3:51 PM EDT | Severe Thunderstorm Warning | PHI | Middlesex | 24 min |
| Jul 17, 4:55 PM EDT | Severe Thunderstorm Warning | PHI | Hunterdon, Somerset | 50 min |
| Jul 17, 5:19 PM EDT | Tornado Warning | PHI | Hunterdon | 14 min |
| Jul 17, 5:52 PM EDT | Areal Flood Advisory | PHI | Somerset | 2 hr |
| Jul 17, 6:15 PM EDT | Flash Flood Warning | PHI | Morris, Somerset | 5 hr |
| Jul 17, 6:59 PM EDT | Small Craft Advisory | PHI | 7 hr |
Nearby
Severe Thunderstorm Warnings in New Jersey, 2021Severe Thunderstorm Warnings in Pennsylvania, 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.