Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 11, NWS Philadelphia/Mount Holly

April 21, 20215 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 21, 2021, 1:10 PM EDT for 5 counties in New Jersey; 5 counties in Pennsylvania; New Castle County, Delaware. It was in force for 50 min. 10 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: Apr 21, 2021, 1:10 PM EDT (17:10 UTC)
Expired: Apr 21, 2021, 2:00 PM EDT
In force: 50 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Mercer County, NJ, Salem County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 17:13 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
Apr 21, 1:15 PM EDT	HAIL 0.25	1 Ne Brookfield, PA
Apr 21, 1:15 PM EDT	HAIL 0.25	1 Nw Talleyville, DE
Apr 21, 1:35 PM EDT	HAIL 0.25	Springfield, PA
Apr 21, 1:36 PM EDT	TSTM WND GST 52	Philadelphia Internatio, PA	ASOS STATION KPHL PHILADELPHIA INTERNATIONAL AIRPORT.
Apr 21, 1:40 PM EDT	TSTM WND DMG	1 Ssw Wyncote, PA	TREE LIMBS DOWN ON WIRES ON ROCK CREEK DR. TIME ESTIMATED FROM RADAR.
Apr 21, 1:40 PM EDT	TSTM WND GST 59	1 Sse South Philadelphi, PA	PENNDOT RWIS STATION AT I-95 AND GIRARD AVENUE.
Apr 21, 1:45 PM EDT	TSTM WND DMG	1 Se Flourtown, PA	TREE DOWN ON WIRES ON TYSON RD. TIME ESTIMATED FROM RADAR.
Apr 21, 1:48 PM EDT	HAIL 0.25	1 Se Point Breeze, PA
Apr 21, 1:58 PM EDT	TSTM WND DMG	1 N Holmesburg, PA	POWER OUTAGE DUE TO SEVERE WEATHER NEAR HOLME CIRCLE. TIME ESTIMATED FROM RADAR.
Apr 21, 2:00 PM EDT	HAIL 0.7	1 Ene Lawrenceville, 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
Apr 21, 12:28 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.2 hours before the alert went out and 214 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 8 J/kg
Mixed-layer CIN: -277 J/kg
Mixed-layer LCL: 1577 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 128 m²/s²
0-3 km storm-relative helicity: 109 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

983 
WUUS51 KPHI 211710
SVRPHI
DEC003-NJC005-007-015-021-033-PAC017-029-045-091-101-211800-
/O.NEW.KPHI.SV.W.0011.210421T1710Z-210421T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
110 PM EDT Wed Apr 21 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...
  Northwestern Camden County in southern New Jersey...
  Central Mercer County in central New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Northwestern Burlington County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Southeastern Bucks County in southeastern Pennsylvania...
  Southeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 200 PM EDT.

* At 109 PM EDT, severe thunderstorms were located along a line
  extending from near Cheyney to near Stanton, moving northeast at 60
  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...
  Philadelphia, Trenton, Camden, Wilmington, Newark, West Chester,
  Gloucester City, Cherry Hill, Bensalem, Evesham, Mount Laurel,
  Ewing, Chester, Willingboro, Deptford, West Deptford, Princeton,
  Florence, Bellmawr and Yeadon.

People at the Esperanza Community Vaccination Site, Burlington County
Mega Site, and Pennsylvania Convention Center Vaccination Site should
seek safe shelter immediately!

This includes the following highways...
 New Jersey Turnpike between exits 3 and 6A.
 Pennsylvania Turnpike between mile markers 333 and 359.
 Interstate 95 in Pennsylvania between mile markers 0 and 40.
 Interstate 95 in Delaware between mile markers 2 and 23.
 Interstate 76 in Pennsylvania between mile markers 329 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 7 and 50, and
between mile markers 68 and 76.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 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.

&&

LAT...LON 3999 7558 4039 7465 3989 7486 3962 7578
TIME...MOT...LOC 1709Z 242DEG 54KT 3997 7552 3967 7566 

HAIL...1.00IN
WIND...60MPH
 
$$

JEO

3 follow-up statements

345 
WWUS51 KPHI 211731
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
131 PM EDT Wed Apr 21 2021

NJC033-PAC029-211741-
/O.CAN.KPHI.SV.W.0011.000000T0000Z-210421T1800Z/
Salem NJ-Chester PA-
131 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN SALEM AND
SOUTHEASTERN CHESTER COUNTIES 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 600 PM EDT for
northern Delaware...southern and central New Jersey...and
southeastern Pennsylvania.

LAT...LON 4039 7465 3989 7486 3978 7540 3978 7544
      3976 7546 3975 7552 3998 7546 3998 7544
      4000 7545 4003 7540 4004 7541
TIME...MOT...LOC 1731Z 242DEG 54KT 4012 7516 3982 7530 

$$

DEC003-NJC005-007-015-021-PAC017-045-091-101-211800-
/O.CON.KPHI.SV.W.0011.000000T0000Z-210421T1800Z/
New Castle DE-Camden NJ-Mercer NJ-Gloucester NJ-Burlington NJ-
Montgomery PA-Bucks PA-Philadelphia PA-Delaware PA-
131 PM EDT Wed Apr 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR NORTHEASTERN NEW CASTLE...NORTHWESTERN CAMDEN...CENTRAL MERCER...
NORTHWESTERN GLOUCESTER...NORTHWESTERN BURLINGTON...SOUTHEASTERN
MONTGOMERY...SOUTHEASTERN BUCKS...PHILADELPHIA AND DELAWARE
COUNTIES...

At 131 PM EDT, severe thunderstorms were located along a line
extending from near Jenkintown to Gibbstown, moving northeast at 60
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...
Philadelphia, Trenton, Camden, Gloucester City, Cherry Hill,
Bensalem, Mount Laurel, Ewing, Chester, Willingboro, West Deptford,
Princeton, Florence, Bellmawr, Yeadon, Woodbury, Burlington, Bristol,
Riverside and Conshohocken.

People at the Esperanza Community Vaccination Site, Burlington County
Mega Site, and Pennsylvania Convention Center Vaccination Site should
seek safe shelter immediately!

This includes the following highways...
 New Jersey Turnpike between exits 3 and 6A.
 Pennsylvania Turnpike between mile markers 337 and 359.
 Interstate 95 in Pennsylvania between mile markers 0 and 40.
 Interstate 95 in Delaware between mile markers 18 and 23.
 Interstate 76 in Pennsylvania between mile markers 331 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 14 and 50, and
between mile markers 68 and 76.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 476 in Pennsylvania between mile markers 0 and 17.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4039 7465 3989 7486 3978 7540 3978 7544
      3976 7546 3975 7552 3998 7546 3998 7544
      4000 7545 4003 7540 4004 7541
TIME...MOT...LOC 1731Z 242DEG 54KT 4012 7516 3982 7530 

HAIL...1.00IN
WIND...60MPH
 
$$

JEO

822 
WWUS51 KPHI 211747
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
147 PM EDT Wed Apr 21 2021

DEC003-211756-
/O.CAN.KPHI.SV.W.0011.000000T0000Z-210421T1800Z/
New Castle DE-
147 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN NEW CASTLE 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 600 PM EDT for
southern and central New Jersey...and southeastern Pennsylvania.

LAT...LON 4039 7465 3989 7486 3980 7531 4004 7536
TIME...MOT...LOC 1746Z 242DEG 54KT 4021 7495 3991 7509 

$$

NJC005-007-015-021-PAC017-045-091-101-211800-
/O.CON.KPHI.SV.W.0011.000000T0000Z-210421T1800Z/
Camden NJ-Mercer NJ-Gloucester NJ-Burlington NJ-Montgomery PA-
Bucks PA-Philadelphia PA-Delaware PA-
147 PM EDT Wed Apr 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR NORTHWESTERN CAMDEN...CENTRAL MERCER...NORTHWESTERN GLOUCESTER...
NORTHWESTERN BURLINGTON...SOUTHEASTERN MONTGOMERY...SOUTHEASTERN
BUCKS...PHILADELPHIA AND EASTERN DELAWARE COUNTIES...

At 146 PM EDT, severe thunderstorms were located along a line
extending from Newtown to Audubon Park, moving northeast at 60 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated. These storms have shown signs of 
         weakening, but a wind gust to 52 mph was just reported at 
         Philadelphia International Airport.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Philadelphia, Trenton, Camden, Gloucester City, Cherry Hill,
Bensalem, Mount Laurel, Ewing, Willingboro, West Deptford, Princeton,
Florence, Bellmawr, Yeadon, Woodbury, Burlington, Bristol, Riverside,
Palmyra and Folcroft.

People at the Esperanza Community Vaccination Site, Burlington County
Mega Site, and Pennsylvania Convention Center Vaccination Site should
seek safe shelter immediately!

This includes the following highways...
 New Jersey Turnpike between exits 3 and 6A.
 Pennsylvania Turnpike between mile markers 344 and 359.
 Interstate 95 in Pennsylvania between mile markers 8 and 40.
 Interstate 76 in Pennsylvania between mile markers 333 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 295 in New Jersey between mile markers 15 and 50, and
between mile markers 68 and 76.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 476 in Pennsylvania between mile markers 7 and 10, and
near mile marker 13.

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.

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4039 7465 3989 7486 3980 7531 4004 7536
TIME...MOT...LOC 1746Z 242DEG 54KT 4021 7495 3991 7509 

HAIL...<.75IN
WIND...60MPH
 
$$

JEO

129 
WWUS51 KPHI 211755
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
155 PM EDT Wed Apr 21 2021

NJC005-007-015-021-PAC017-045-091-101-211805-
/O.EXP.KPHI.SV.W.0011.000000T0000Z-210421T1800Z/
Camden NJ-Mercer NJ-Gloucester NJ-Burlington NJ-Montgomery PA-
Bucks PA-Philadelphia PA-Delaware PA-
155 PM EDT Wed Apr 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN CAMDEN...CENTRAL
MERCER...NORTHWESTERN GLOUCESTER...NORTHWESTERN BURLINGTON...
SOUTHEASTERN MONTGOMERY...SOUTHEASTERN BUCKS...PHILADELPHIA AND
EASTERN DELAWARE COUNTIES WILL EXPIRE AT 200 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.  However gusty
winds are still possible with these thunderstorms.

A Severe Thunderstorm Watch remains in effect until 600 PM EDT for
southern and central New Jersey...and southeastern Pennsylvania.

LAT...LON 4039 7465 3989 7486 3980 7531 4004 7536
TIME...MOT...LOC 1755Z 242DEG 54KT 4021 7495 3991 7509 

$$

JEO

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 20, 8:48 PM EDT	Freeze Watch	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	7 hr
Apr 21, 3:26 AM EDT	Freeze Warning	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	30 hr
Apr 21, 12:25 PM EDT	Severe Thunderstorm Warning	PHI	Warren	50 min
Apr 21, 12:51 PM EDT	Severe Thunderstorm Warning	PHI	Sussex, Warren	21 min
Apr 21, 12:55 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Warren	27 min
Apr 21, 1:17 PM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset, Sussex	58 min
Apr 21, 1:28 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester	36 min
Apr 21, 1:30 PM EDT	Special Marine Warning	PHI		60 min
Apr 21, 1:43 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Middlesex, Morris, Somerset	33 min
Apr 21, 1:58 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Monmouth, Ocean	62 min
Apr 21, 2:02 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Camden, Monmouth, Ocean	43 min
Apr 21, 2:03 PM EDT	Special Weather Statement	PHI	Cumberland	27 min
Apr 21, 2:17 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cumberland, Gloucester, Salem	43 min
Apr 21, 2:28 PM EDT	Special Weather Statement	PHI	Middlesex, Monmouth	47 min
Apr 21, 2:30 PM EDT	Special Marine Warning	PHI		60 min
Apr 21, 2:38 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	37 min
Apr 21, 2:40 PM EDT	Special Marine Warning	PHI		55 min
Apr 21, 2:43 PM EDT	Special Weather Statement	PHI	Cape May	32 min
Apr 21, 2:50 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Ocean	40 min
Apr 21, 3:02 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic	28 min
Apr 21, 3:07 PM EDT	Special Marine Warning	PHI		53 min
Apr 21, 12:03 PM EDT	Special Weather Statement	PHI	Chester, Lehigh	42 min
Apr 21, 12:17 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	43 min
Apr 21, 12:54 PM EDT	Special Weather Statement	PHI	Delaware	36 min
Apr 21, 1:23 PM EDT	Severe Thunderstorm Warning	PHI	Kent	37 min
Apr 21, 2:09 PM EDT	Special Weather Statement	PHI	Sussex	36 min
Apr 21, 2:18 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	42 min
Apr 21, 2:47 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	16 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2021 Severe Thunderstorm Warnings in Pennsylvania, 2021 Severe Thunderstorm Warnings in Delaware, 2021 Every 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.