Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 323, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Dec 11, 2021, 9:01 PM EST for 8 counties in Pennsylvania; New Castle County, Delaware. It was in force for 48 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
- Dec 11, 2021, 9:01 PM EST (02:01 UTC)
- Expired
- Dec 11, 2021, 9:49 PM EST
- In force
- 48 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Tornado
- Possible
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties New Castle County, DE, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 95 km from the middle of the area, began a volume at 02:05 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 00:00Z, 2.0 hours before the alert went out and 207 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
- 1263 m above ground
- 0-6 km bulk shear
- 77 kt
- 0-1 km storm-relative helicity
- 187 m²/s²
- 0-3 km storm-relative helicity
- 12 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
026
WUUS51 KPHI 120201
SVRPHI
DEC003-PAC011-017-029-045-077-091-095-101-120300-
/O.NEW.KPHI.SV.W.0323.211212T0201Z-211212T0300Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
901 PM EST Sat Dec 11 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Northern New Castle County in northern Delaware...
Southeastern Berks County in eastern Pennsylvania...
Southeastern Lehigh County in eastern Pennsylvania...
Montgomery County in southeastern Pennsylvania...
Bucks County in southeastern Pennsylvania...
Chester County in southeastern Pennsylvania...
Western Philadelphia County in southeastern Pennsylvania...
Delaware County in southeastern Pennsylvania...
South central Northampton County in eastern Pennsylvania...
* Until 1000 PM EST.
* At 900 PM EST, severe thunderstorms were located along a line
extending from Alpha to Rising Sun, moving east at 35 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Philadelphia, Allentown, Wilmington, Newark, Easton, West Chester,
Bethlehem, Norristown, Chester, Pottstown, Phoenixville, Lansdale,
West Norriton, Forks, East Norriton, Pennsville, Coatesville,
Yeadon, Emmaus and Westtown.
This includes the following highways...
Pennsylvania Turnpike between mile markers 296 and 350.
Northeast Extension between mile markers 21 and 52.
Interstate 95 in Pennsylvania between mile markers 0 and 11.
Interstate 95 in Delaware between mile markers 7 and 23.
Interstate 76 in Pennsylvania between mile markers 327 and 346.
Interstate 78 in Pennsylvania between mile markers 59 and 76.
Interstate 295 in New Jersey near mile marker 0.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
Interstate 176 in Pennsylvania between mile markers 1 and 2.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.
&&
LAT...LON 3987 7599 4011 7594 4014 7588 4018 7593
4077 7526 4075 7519 4057 7519 4054 7507
4042 7506 4040 7497 4028 7485 3985 7528
3984 7536 3977 7546 3966 7551 3968 7579
3972 7579 3972 7613
TIME...MOT...LOC 0200Z 270DEG 31KT 4064 7518 3973 7607
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Davis2 follow-up statements
500
WWUS51 KPHI 120229
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
929 PM EST Sat Dec 11 2021
PAC011-077-095-120239-
/O.CAN.KPHI.SV.W.0323.000000T0000Z-211212T0300Z/
Berks PA-Lehigh PA-Northampton PA-
929 PM EST Sat Dec 11 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS...
SOUTHEASTERN LEHIGH AND SOUTH CENTRAL NORTHAMPTON COUNTIES IS
CANCELLED...
The storms which prompted the warning have moved out of the warned
area. Therefore, the warning has been cancelled.
LAT...LON 4007 7568 4056 7516 4054 7507 4042 7506
4040 7497 4033 7494 4028 7485 3985 7528
3984 7536 3977 7546 3966 7552 3968 7579
3982 7582
TIME...MOT...LOC 0229Z 270DEG 31KT 4064 7488 3973 7577
$$
DEC003-PAC017-029-045-091-101-120300-
/O.CON.KPHI.SV.W.0323.000000T0000Z-211212T0300Z/
New Castle DE-Montgomery PA-Bucks PA-Chester PA-Philadelphia PA-
Delaware PA-
929 PM EST Sat Dec 11 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 PM EST
FOR NORTHERN NEW CASTLE...MONTGOMERY...BUCKS...EASTERN CHESTER...
WESTERN PHILADELPHIA AND DELAWARE COUNTIES...
At 929 PM EST, severe thunderstorms were located along a line
extending from Annandale to Glen Westover, moving east at 35 mph.
HAZARD...60 mph wind gusts.
SOURCE...Public.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Philadelphia, Wilmington, Newark, West Chester, Norristown, Chester,
Phoenixville, Lansdale, West Norriton, East Norriton, Pennsville,
Yeadon, Westtown, Perkasie, Doylestown, Byram, Downingtown,
Conshohocken, Hatboro and Souderton.
This includes the following highways...
Pennsylvania Turnpike between mile markers 312 and 350.
Northeast Extension between mile markers 21 and 37.
Interstate 95 in Pennsylvania between mile markers 0 and 11.
Interstate 95 in Delaware between mile markers 7 and 23.
Interstate 76 in Pennsylvania between mile markers 327 and 346.
Interstate 295 in New Jersey near mile marker 0.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 0 and 19.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
This severe thunderstorm may contain little or no lightning. Do not
wait until you hear thunder before taking cover.
&&
LAT...LON 4007 7568 4056 7516 4054 7507 4042 7506
4040 7497 4033 7494 4028 7485 3985 7528
3984 7536 3977 7546 3966 7552 3968 7579
3982 7582
TIME...MOT...LOC 0229Z 270DEG 31KT 4064 7488 3973 7577
TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Davis775
WWUS51 KPHI 120249
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
949 PM EST Sat Dec 11 2021
DEC003-PAC017-029-045-091-101-120258-
/O.CAN.KPHI.SV.W.0323.000000T0000Z-211212T0300Z/
New Castle DE-Montgomery PA-Bucks PA-Chester PA-Philadelphia PA-
Delaware PA-
949 PM EST Sat Dec 11 2021
...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN NEW CASTLE...
MONTGOMERY...BUCKS...EASTERN CHESTER...WESTERN PHILADELPHIA AND
DELAWARE COUNTIES IS CANCELLED...
The storms which prompted the warning have moved out of the area.
Therefore, the warning has been cancelled. However gusty winds are
still possible with these thunderstorms.
To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.
LAT...LON 4007 7568 4056 7516 4054 7507 4042 7506
4040 7497 4033 7494 4028 7485 3985 7528
3984 7536 3977 7546 3966 7552 3968 7579
3982 7582
TIME...MOT...LOC 0247Z 270DEG 31KT 4064 7467 3973 7556
$$
DavisNearby
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.