Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 312, NWS Philadelphia/Mount Holly

September 28, 2021Gloucester County, Salem County, New Jersey; Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 28, 2021, 7:29 PM EDT for Gloucester County, Salem County, New Jersey; Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 31 min. 1 report 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
Sep 28, 2021, 7:29 PM EDT (23:29 UTC)
Expired
Sep 28, 2021, 8:00 PM EDT
In force
31 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties New Castle County, DE, Gloucester County, NJ, Salem County, NJ, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 23:32 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

TimeReportWhereRemark
Sep 28, 7:32 PM EDTTSTM WND DMGUpper Chichester Twp, PASHINGLES BLOWN OFF A ROOF AND MINOR TREE DAMAGE IN UPPER CHICHESTER TOWNSHIP. TIME ESTIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.5 hours before the alert went out and 211 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2021-09-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 35 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2021-09-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 38 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
35 J/kg
Mixed-layer CIN
-322 J/kg
Mixed-layer LCL
1669 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
38 m²/s²
0-3 km storm-relative helicity
138 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

453 
WUUS51 KPHI 282329
SVRPHI
DEC003-NJC015-033-PAC045-290000-
/O.NEW.KPHI.SV.W.0312.210928T2329Z-210929T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
729 PM EDT Tue Sep 28 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northeastern New Castle County in northern Delaware...
  Northeastern Salem County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Delaware County in southeastern Pennsylvania...

* Until 800 PM EDT.

* At 729 PM EDT, a severe thunderstorm was located over Chelsea, or
  10 miles southeast of West Chester, moving southeast at 30 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...
  Chester, Deptford, West Deptford, Glassboro, Woodbury, Pitman,
  Folcroft, Swarthmore, Paulsboro, Woodstown, Woodbury Heights,
  National Park, Swedesboro, Arden, Darby Township, Elam, Chelsea,
  Gradyville, Chester Township and Mullica Hill.

This includes the following highways...
 New Jersey Turnpike near exit 2.
 Interstate 95 in Pennsylvania between mile markers 0 and 11.
 Interstate 95 in Delaware between mile markers 19 and 23.
 Interstate 295 in New Jersey between mile markers 7 and 23.
 Interstate 476 in Pennsylvania between mile markers 0 and 6.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4000 7543 3991 7525 3987 7526 3987 7519
      3982 7508 3980 7507 3978 7509 3979 7506
      3975 7504 3958 7525 3986 7559
TIME...MOT...LOC 2329Z 311DEG 26KT 3989 7544 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

PO
1 follow-up statement
194 
WWUS51 KPHI 282351
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
751 PM EDT Tue Sep 28 2021

DEC003-NJC015-033-PAC045-290000-
/O.CON.KPHI.SV.W.0312.000000T0000Z-210929T0000Z/
New Castle DE-Salem NJ-Gloucester NJ-Delaware PA-
751 PM EDT Tue Sep 28 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR NORTHEASTERN NEW CASTLE...NORTH CENTRAL SALEM...NORTHWESTERN
GLOUCESTER AND SOUTHERN DELAWARE COUNTIES...

At 751 PM EDT, a severe thunderstorm was located over Beckett, or 10
miles east of Wilmington, moving southeast at 25 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...
Chester, Deptford, West Deptford, Glassboro, Woodbury, Pitman,
Folcroft, Swarthmore, Paulsboro, Woodstown, Woodbury Heights,
Swedesboro, Arden, Chelsea, Beckett, Nether Providence Township,
Chester Township, Philadelphia International Arpt, Mullica Hill and
Gibbstown.

This includes the following highways...
 New Jersey Turnpike near exit 2.
 Interstate 95 in Pennsylvania between mile markers 0 and 10.
 Interstate 95 in Delaware between mile markers 20 and 23.
 Interstate 295 in New Jersey between mile markers 7 and 21.
 Interstate 476 in Pennsylvania between mile markers 0 and 2.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3991 7534 3989 7529 3987 7526 3985 7519
      3981 7510 3979 7510 3978 7509 3977 7509
      3975 7507 3961 7527 3984 7556
TIME...MOT...LOC 2351Z 329DEG 22KT 3977 7533 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

PO

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 28, 8:26 AM EDTAreal Flood AdvisoryPHIWarren2 hr
Sep 28, 7:14 PM EDTSpecial Weather StatementPHIGloucester46 min
Sep 28, 9:23 AM EDTSpecial Weather StatementPHIMontgomery37 min
Sep 28, 9:47 AM EDTSpecial Weather StatementPHIBucks, Montgomery28 min
Sep 28, 6:15 PM EDTSpecial Weather StatementPHIChester45 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2021Severe 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.