Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 173, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 12, 2021, 7:06 PM EDT for Salem County, New Jersey; New Castle County, Delaware; Chester County, Delaware County, Pennsylvania. It was in force for 69 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 12, 2021, 7:06 PM EDT (23:06 UTC)
- Expired
- Jul 12, 2021, 8:15 PM EDT
- In force
- 69 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties New Castle County, DE, Salem County, NJ, Chester County, PA, Delaware County, PA
The radar
The Dover AFB radar (KDOX), 109 km from the middle of the area, began a volume at 23:07 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, 7:29 PM EDT | TSTM WND DMG | 1 N Rose Hill Gardens, DE | A COUPLE OF REPORTS OF DOWNED WIRES NEAR ROGERS ROAD AND NEW CASTLE AVENUE. TIME ESTIMATED FROM RADAR. |
| Jul 12, 7:36 PM EDT | TSTM WND DMG | Wilmington, DE | A COUPLE OF REPORTS OF DOWNED WIRES NEAR 10TH STREET. 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
Washington/Dulle, VA (KIAD), launched 12:00Z, 11.1 hours before the alert went out and 166 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
- 974 J/kg
- Mixed-layer CIN
- -83 J/kg
- Mixed-layer LCL
- 724 m above ground
- 0-6 km bulk shear
- 21 kt
- 0-1 km storm-relative helicity
- 10 m²/s²
- 0-3 km storm-relative helicity
- 53 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.8
The text
As transmitted.
919
WUUS51 KPHI 122306
SVRPHI
DEC003-NJC033-PAC029-045-130015-
/O.NEW.KPHI.SV.W.0173.210712T2306Z-210713T0015Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
706 PM EDT Mon Jul 12 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Northern New Castle County in northern Delaware...
Northwestern Salem County in southern New Jersey...
Southwestern Chester County in southeastern Pennsylvania...
Southwestern Delaware County in southeastern Pennsylvania...
* Until 815 PM EDT.
* At 705 PM EDT, severe thunderstorms were located along a line
extending from Homeville to near Octoraro, moving east at 20 mph.
Another storm was developing near Newark and could potentially
become severe as well.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Wilmington, Newark, Pennsville, Carneys Point, Elsmere, Kennett
Square, New Castle, Penns Grove, Oxford, West Grove, Newport,
Arden, Homeville, Glen Roy, Stanton, North Star, Glasgow, Bear,
Talleyville and Wilmington Manor.
This includes the following highways...
Interstate 95 in Pennsylvania near mile marker 0.
Interstate 95 in Delaware between mile markers 1 and 23.
Interstate 295 in New Jersey between mile markers 0 and 5.
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 these storms. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.
&&
LAT...LON 3976 7608 3976 7606 3987 7601 3988 7599
3993 7556 3979 7541 3978 7544 3978 7540
3959 7548 3960 7578 3972 7579 3972 7610
TIME...MOT...LOC 2305Z 255DEG 16KT 3984 7599 3961 7618
HAIL...<.75IN
WIND...60MPH
$$
CMS3 follow-up statements
606
WWUS51 KPHI 122339
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
739 PM EDT Mon Jul 12 2021
PAC045-122349-
/O.CAN.KPHI.SV.W.0173.000000T0000Z-210713T0015Z/
Delaware PA-
739 PM EDT Mon Jul 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN DELAWARE COUNTY
IS CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern Delaware...southern New Jersey...and southeastern
Pennsylvania.
LAT...LON 3976 7608 3976 7606 3982 7603 3982 7565
3979 7542 3978 7544 3977 7540 3959 7548
3960 7578 3972 7579 3972 7610
TIME...MOT...LOC 2339Z 254DEG 17KT 3970 7544 3965 7600
$$
DEC003-NJC033-PAC029-130015-
/O.CON.KPHI.SV.W.0173.000000T0000Z-210713T0015Z/
New Castle DE-Salem NJ-Chester PA-
739 PM EDT Mon Jul 12 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR NORTHERN NEW CASTLE...NORTHWESTERN SALEM AND SOUTHWESTERN CHESTER
COUNTIES...
At 739 PM EDT, severe thunderstorms were located along a line
extending from Carneys Point to near Bay View, moving east at 20 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Wilmington, Newark, Pennsville, Carneys Point, Elsmere, New Castle,
Penns Grove, Oxford, West Grove, Newport, Glen Roy, Stanton, North
Star, Glasgow, Bear, Wilmington Manor, Mount Vernon, Pike Creek,
Ashland and Greenville.
This includes the following highways...
Interstate 95 in Delaware between mile markers 1 and 19.
Interstate 295 in New Jersey between mile markers 0 and 6.
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 these storms.
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 3976 7608 3976 7606 3982 7603 3982 7565
3979 7542 3978 7544 3977 7540 3959 7548
3960 7578 3972 7579 3972 7610
TIME...MOT...LOC 2339Z 254DEG 17KT 3970 7544 3965 7600
HAIL...<.75IN
WIND...60MPH
$$
CMS653
WWUS51 KPHI 130001
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
801 PM EDT Mon Jul 12 2021
PAC029-130011-
/O.CAN.KPHI.SV.W.0173.000000T0000Z-210713T0015Z/
Chester PA-
801 PM EDT Mon Jul 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN CHESTER COUNTY IS
CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern Delaware...and southern New Jersey.
LAT...LON 3973 7542 3961 7547 3959 7548 3960 7574
3960 7578 3970 7579
TIME...MOT...LOC 0001Z 252DEG 16KT 3970 7540 3965 7596
$$
DEC003-NJC033-130015-
/O.CON.KPHI.SV.W.0173.000000T0000Z-210713T0015Z/
New Castle DE-Salem NJ-
801 PM EDT Mon Jul 12 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR NORTHERN NEW CASTLE AND NORTHWESTERN SALEM COUNTIES...
At 801 PM EDT, severe thunderstorms were located along a line
extending from near Carneys Point to Bay View, moving east at 20 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Wilmington, Newark, Pennsville, Carneys Point, New Castle, Penns
Grove, Newport, Wilmington Manor, Glasgow, Bear, Delaware Memorial
Bridge and Brookside.
This includes the following highways...
Interstate 95 in Delaware between mile markers 1 and 11.
Interstate 295 in New Jersey between mile markers 0 and 6.
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 3973 7542 3961 7547 3959 7548 3960 7574
3960 7578 3970 7579
TIME...MOT...LOC 0001Z 252DEG 16KT 3970 7540 3965 7596
HAIL...<.75IN
WIND...60MPH
$$
CMS915
WWUS51 KPHI 130009
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
809 PM EDT Mon Jul 12 2021
DEC003-NJC033-130019-
/O.EXP.KPHI.SV.W.0173.000000T0000Z-210713T0015Z/
New Castle DE-Salem NJ-
809 PM EDT Mon Jul 12 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN NEW CASTLE AND
NORTHWESTERN SALEM COUNTIES WILL EXPIRE AT 815 PM EDT...
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.
A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
northern Delaware...and southern New Jersey.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.
LAT...LON 3973 7542 3961 7547 3959 7548 3960 7574
3960 7578 3970 7579
TIME...MOT...LOC 0009Z 255DEG 16KT 3971 7536 3966 7592
$$
CMSThe 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 | 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, 5:57 PM EDT | Severe Thunderstorm Warning | PHI | Morris, Sussex | 63 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, 7:11 PM EDT | Flash Flood Warning | PHI | Morris, Sussex | 35 min |
| Jul 12, 7:33 PM EDT | Special Marine Warning | PHI | 58 min | |
| Jul 11, 10:21 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 24 min |
| Jul 11, 10:22 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Carbon, Lehigh, Monroe, Northampton | 38 min |
| Jul 12, 2:28 PM EDT | Areal Flood Advisory | PHI | Chester | 3 hr |
| Jul 12, 4:16 PM EDT | Areal Flood Advisory | PHI | Bucks, Montgomery, Philadelphia | 114 min |
| Jul 12, 5:41 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 34 min |
| Jul 12, 6:18 PM EDT | Flash Flood Warning | PHI | Delaware | 84 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2021Severe Thunderstorm Warnings in New Jersey, 2021Severe Thunderstorm Warnings in Delaware, 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.