Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 157, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 9, 2021, 5:17 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 9, 2021, 5:17 PM EDT (21:17 UTC)
- Expired
- Jul 9, 2021, 6:00 PM EDT
- In force
- 43 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties New Castle County, DE, 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 21:21 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.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 9.3 hours before the alert went out and 157 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 862 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 42 m²/s²
- 0-3 km storm-relative helicity
- 55 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
352
WUUS51 KPHI 092117
SVRPHI
DEC003-PAC029-045-092200-
/O.NEW.KPHI.SV.W.0157.210709T2117Z-210709T2200Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
517 PM EDT Fri Jul 9 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Northwestern New Castle County in northern Delaware...
Southwestern Chester County in southeastern Pennsylvania...
Southwestern Delaware County in southeastern Pennsylvania...
* Until 600 PM EDT.
* At 517 PM EDT, a severe thunderstorm was located over Glen Roy, or
14 miles north of Havre De Grace, 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...
Wilmington, Newark, Elsmere, Kennett Square, New Castle, Oxford,
West Grove, Newport, Arden, Glen Roy, Stanton, North Star, Bear,
Talleyville, Wilmington Manor, Elam, Mount Vernon, Pike Creek,
Ashland and Greenville.
This includes the following highways...
Interstate 95 in Delaware between mile markers 0 and 19.
Interstate 295 in New Jersey near mile marker 0.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3973 7610 3974 7609 3976 7606 3981 7603
3983 7604 3983 7602 3986 7601 3987 7547
3968 7551 3963 7556 3959 7555 3962 7579
3972 7579 3972 7613
TIME...MOT...LOC 2117Z 272DEG 25KT 3976 7608
HAIL...<.75IN
WIND...60MPH
$$
NC2 follow-up statements
086
WWUS51 KPHI 092140
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
540 PM EDT Fri Jul 9 2021
PAC045-092150-
/O.CAN.KPHI.SV.W.0157.000000T0000Z-210709T2200Z/
Delaware PA-
540 PM EDT Fri Jul 9 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN DELAWARE COUNTY
IS CANCELLED...
The severe thunderstorm which prompted the warning has weakened
Therefore, the warning has been cancelled.
LAT...LON 3976 7606 3981 7603 3983 7604 3984 7599
3983 7558 3973 7551 3968 7551 3963 7556
3959 7555 3962 7579 3972 7579 3973 7610
TIME...MOT...LOC 2140Z 272DEG 25KT 3975 7587
$$
DEC003-PAC029-092200-
/O.CON.KPHI.SV.W.0157.000000T0000Z-210709T2200Z/
New Castle DE-Chester PA-
540 PM EDT Fri Jul 9 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 600 PM EDT
FOR NORTHWESTERN NEW CASTLE AND SOUTHWESTERN CHESTER COUNTIES...
At 540 PM EDT, a severe thunderstorm was located over Kemblesville,
or 7 miles northwest of Newark, 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...
Wilmington, Newark, Elsmere, New Castle, Oxford, West Grove, Newport,
Glen Roy, Greenville, Stanton, North Star, Bear, Delaware Memorial
Bridge, Wilmington Manor, Mount Vernon, Ladenberg, Pike Creek,
Kemblesville, Hockessin and Ashland.
This includes Interstate 95 in Delaware between mile markers 0 and
16.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3976 7606 3981 7603 3983 7604 3984 7599
3983 7558 3973 7551 3968 7551 3963 7556
3959 7555 3962 7579 3972 7579 3973 7610
TIME...MOT...LOC 2140Z 272DEG 25KT 3975 7587
HAIL...<.75IN
WIND...60MPH
$$
NC769
WWUS51 KPHI 092151
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
551 PM EDT Fri Jul 9 2021
DEC003-PAC029-092201-
/O.EXP.KPHI.SV.W.0157.000000T0000Z-210709T2200Z/
New Castle DE-Chester PA-
551 PM EDT Fri Jul 9 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN NEW CASTLE AND
SOUTHWESTERN CHESTER COUNTIES WILL EXPIRE AT 600 PM EDT...
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.
LAT...LON 3976 7606 3981 7603 3983 7604 3984 7599
3983 7558 3973 7551 3968 7551 3963 7556
3959 7555 3962 7579 3972 7579 3973 7610
TIME...MOT...LOC 2151Z 272DEG 25KT 3975 7577
$$
NCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 9, 2:05 AM EDT | Areal Flood Advisory | PHI | Philadelphia | 8 hr |
| Jul 9, 4:44 AM EDT | Areal Flood Advisory | PHI | Bucks, Philadelphia | 5 hr |
| Jul 9, 6:55 PM EDT | Special Weather Statement | PHI | Carbon | 35 min |
| Jul 9, 7:07 PM EDT | Areal Flood Advisory | PHI | Carbon, Lehigh, Monroe, Northampton | 3 hr |
| Jul 9, 7:17 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 23 min |
| Jul 9, 7:31 PM EDT | Special Weather Statement | PHI | Northampton | 29 min |
| Jul 9, 7:39 PM EDT | Areal Flood Advisory | PHI | Monroe, Northampton | 2 hr |
| Jul 8, 10:19 PM EDT | Areal Flood Advisory | PHI | Kent, Sussex | 5 hr |
| Jul 8, 11:37 PM EDT | Tornado Warning | PHI | Sussex | 23 min |
| Jul 8, 11:59 PM EDT | Tornado Warning | PHI | Sussex | 12 min |
| Jul 9, 12:04 AM EDT | Tornado Warning | PHI | Sussex | 26 min |
| Jul 9, 12:11 AM EDT | Tornado Warning | PHI | Sussex | 35 min |
| Jul 9, 12:28 AM EDT | Tornado Warning | PHI | Sussex | 17 min |
| Jul 9, 4:54 PM EDT | Special Weather Statement | PHI | New Castle | 66 min |
| Jul 9, 6:19 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 41 min |
| Jul 9, 6:50 PM EDT | Areal Flood Advisory | PHI | New Castle | 2 hr |
| Jul 9, 6:57 PM EDT | Severe Thunderstorm Warning | PHI | New Castle | 63 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.