Alert archive / New Jersey / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 193, NWS Philadelphia/Mount Holly

July 17, 20214 counties in New Jersey; Bucks County, Montgomery County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2021, 8:00 PM EDT for 4 counties in New Jersey; Bucks County, Montgomery County, Philadelphia County, Pennsylvania. It was in force for 45 min. 5 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 17, 2021, 8:00 PM EDT (00:00 UTC)
Expired
Jul 17, 2021, 8:45 PM EDT
In force
45 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Burlington County, NJ, Camden County, NJ, Mercer County, NJ, Monmouth County, NJ, Bucks County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 33 km from the middle of the area, began a volume at 00:04 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
Jul 17, 8:08 PM EDTTSTM WND DMGBensalem, PASEVERAL POWER OUTAGES. LARGE BRANCHES BLOWN DOWN AND SIDING BLOWN OFF A HOUSE. SPOTTER ESTIMATED WINDS ABOVE 60 MPH. TIME ESTIMATED FROM RADAR.
Jul 17, 8:15 PM EDTTSTM WND DMG1 Nw Bensalem, PATREE DOWN.
Jul 17, 8:20 PM EDTTSTM WND DMG2 Nnw Medford Twp., NJSEVERAL LARGE TREES DOWN. TIME APPROXIMATED FROM RADAR.
Jul 17, 8:25 PM EDTTSTM WND DMGMedford, NJSEVERAL TREES BLOWN DOWN. TIME ESTIMATED FROM RADAR.
Jul 17, 8:55 PM EDTTSTM WND GST 581 Ese Lumberton Twp, NJCWOP STATION EW8027 MEASURED GUST.

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.

IssuedProductOfficeLasted
Jul 17, 1:13 PM EDTSevere Thunderstorm WatchSPC10 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 0.0 hours before the alert went out and 187 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, Brookhaven, NY at 00:00Z on 2021-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1431 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, Brookhaven, NY at 00:00Z on 2021-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 26 square meters per square second.1939Sfc1 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
1431 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
988 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
26 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.6

Open this sounding in Storm Lab

The text

As transmitted.

512 
WUUS51 KPHI 180000
SVRPHI
NJC005-007-021-025-PAC017-091-101-180045-
/O.NEW.KPHI.SV.W.0193.210718T0000Z-210718T0045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
800 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Camden County in southern New Jersey...
  Southern Mercer County in central New Jersey...
  Burlington County in southern New Jersey...
  Southwestern Monmouth County in central New Jersey...
  East central Montgomery County in southeastern Pennsylvania...
  Southeastern Bucks County in southeastern Pennsylvania...
  Northeastern Philadelphia County in southeastern Pennsylvania...

* Until 845 PM EDT.

* At 759 PM EDT, severe thunderstorms were located along a line
  extending from Newtown to Erlton-Ellisburg, moving east at 45 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, Evesham, Mount Laurel, Ewing, Willingboro, Voorhees,
  Medford, Lindenwold, Lumberton, Florence, Bellmawr, Burlington,
  Bristol, Mount Holly and Riverside.

This includes the following highways...
 New Jersey Turnpike between exits 3 and 8A.
 Pennsylvania Turnpike between mile markers 345 and 359.
 Interstate 95 in Pennsylvania between mile markers 24 and 40.
 Interstate 76 in New Jersey between mile markers 0 and 2.
 Interstate 195 in New Jersey between mile markers 0 and 11.
 Interstate 295 in New Jersey between mile markers 26 and 76.
 Interstate 676 in New Jersey between mile markers 0 and 4.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4009 7453 4008 7455 4005 7453 3976 7456
      3982 7509 3984 7509 3988 7513 4011 7511
      4033 7503 4027 7451
TIME...MOT...LOC 2359Z 282DEG 37KT 4025 7494 3992 7502 

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

JEO
3 follow-up statements
698 
WWUS51 KPHI 180016
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
816 PM EDT Sat Jul 17 2021

PAC091-101-180025-
/O.CAN.KPHI.SV.W.0193.000000T0000Z-210718T0045Z/
Montgomery PA-Philadelphia PA-
816 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL MONTGOMERY AND
NORTHEASTERN PHILADELPHIA 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 1100 PM EDT for
southern and central New Jersey...and southeastern Pennsylvania.

LAT...LON 4009 7453 4008 7455 4005 7453 3976 7456
      3981 7498 3987 7502 3995 7503 4003 7500
      4008 7496 4012 7497 4032 7493 4027 7451
TIME...MOT...LOC 0015Z 282DEG 37KT 4022 7474 3989 7482 

$$

NJC005-007-021-025-PAC017-180045-
/O.CON.KPHI.SV.W.0193.000000T0000Z-210718T0045Z/
Camden NJ-Mercer NJ-Burlington NJ-Monmouth NJ-Bucks PA-
816 PM EDT Sat Jul 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM EDT
FOR NORTH CENTRAL CAMDEN...SOUTHERN MERCER...BURLINGTON...
SOUTHWESTERN MONMOUTH AND SOUTHEASTERN BUCKS COUNTIES...

At 815 PM EDT, severe thunderstorms were located along a line
extending from Trenton to Medford, moving east at 45 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...
Trenton, Cherry Hill, Bensalem, Evesham, Mount Laurel, Ewing,
Willingboro, Voorhees, Medford, Lindenwold, Lumberton, Florence,
Burlington, Bristol, Mount Holly, Riverside, Tabernacle, Hightstown,
Bordentown and Presidential Lakes Estates.

This includes the following highways...
 New Jersey Turnpike between exits 4 and 8A.
 Pennsylvania Turnpike between mile markers 352 and 359.
 Interstate 95 in Pennsylvania between mile markers 34 and 40.
 Interstate 195 in New Jersey between mile markers 0 and 11.
 Interstate 295 in New Jersey between mile markers 32 and 76.

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 4009 7453 4008 7455 4005 7453 3976 7456
      3981 7498 3987 7502 3995 7503 4003 7500
      4008 7496 4012 7497 4032 7493 4027 7451
TIME...MOT...LOC 0015Z 282DEG 37KT 4022 7474 3989 7482 

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

JEO
557 
WWUS51 KPHI 180023
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
823 PM EDT Sat Jul 17 2021

NJC007-180032-
/O.CAN.KPHI.SV.W.0193.000000T0000Z-210718T0045Z/
Camden NJ-
823 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL CAMDEN 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
southern and central New Jersey...and southeastern Pennsylvania.

LAT...LON 4009 7453 4008 7455 4005 7453 3976 7456
      3981 7491 3988 7493 3995 7498 4002 7498
      4009 7496 4012 7497 4032 7493 4027 7451
TIME...MOT...LOC 0022Z 282DEG 37KT 4021 7468 3988 7476 

$$

NJC005-021-025-PAC017-180045-
/O.CON.KPHI.SV.W.0193.000000T0000Z-210718T0045Z/
Mercer NJ-Burlington NJ-Monmouth NJ-Bucks PA-
823 PM EDT Sat Jul 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM EDT
FOR SOUTHERN MERCER...BURLINGTON...SOUTHWESTERN MONMOUTH AND
SOUTHEASTERN BUCKS COUNTIES...

At 822 PM EDT, severe thunderstorms were located along a line
extending from Mercerville-Hamilton Square to near Medford, moving
east at 45 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated. The highest winds, near to above 70 mph, 
         are expected in the area of Medford.

IMPACT...Minor damage to vehicles is possible. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Trenton, Bensalem, Evesham, Mount Laurel, Ewing, Willingboro,
Medford, Lumberton, Florence, Burlington, Bristol, Mount Holly,
Riverside, Tabernacle, Hightstown, Bordentown, Presidential Lakes
Estates, Beverly, Yardley and Newtown.

This includes the following highways...
 New Jersey Turnpike between exits 4 and 8A.
 Pennsylvania Turnpike between mile markers 352 and 359.
 Interstate 95 in Pennsylvania between mile markers 35 and 40.
 Interstate 195 in New Jersey between mile markers 0 and 11.
 Interstate 295 in New Jersey between mile markers 37 and 76.

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 4009 7453 4008 7455 4005 7453 3976 7456
      3981 7491 3988 7493 3995 7498 4002 7498
      4009 7496 4012 7497 4032 7493 4027 7451
TIME...MOT...LOC 0022Z 282DEG 37KT 4021 7468 3988 7476 

HAIL...1.00IN
WIND...70MPH
 
$$

JEO
935 
WWUS51 KPHI 180040
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
840 PM EDT Sat Jul 17 2021

NJC005-021-025-PAC017-180050-
/O.EXP.KPHI.SV.W.0193.000000T0000Z-210718T0045Z/
Mercer NJ-Burlington NJ-Monmouth NJ-Bucks PA-
840 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN MERCER...
BURLINGTON...SOUTHWESTERN MONMOUTH AND SOUTHEASTERN BUCKS COUNTIES
WILL EXPIRE AT 845 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 1100 PM EDT for
southern and central New Jersey...and southeastern Pennsylvania.

LAT...LON 4009 7453 4008 7455 4005 7453 3976 7456
      3981 7491 3988 7493 3995 7498 4002 7498
      4009 7496 4012 7497 4032 7493 4027 7451
TIME...MOT...LOC 0040Z 282DEG 37KT 4017 7445 3984 7454 

$$

JEO

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 8:09 PM EDTFlash Flood WarningPHIMercer, Somerset4 hr
Jul 17, 8:35 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Gloucester40 min
Jul 17, 8:36 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean, Somerset54 min
Jul 17, 8:46 PM EDTSpecial Marine WarningPHI59 min
Jul 17, 8:53 PM EDTAreal Flood AdvisoryPHIMercer, Middlesex, Monmouth3 hr
Jul 17, 9:25 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Salem2 hr
Jul 17, 9:27 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem48 min
Jul 17, 9:30 PM EDTSevere Thunderstorm WarningPHICape May29 min
Jul 17, 9:36 PM EDTFlash Flood WarningPHICamden, Gloucester, Salem2 hr
Jul 17, 9:44 PM EDTSpecial Marine WarningPHI61 min
Jul 17, 9:48 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Mercer, Salem42 min
Jul 17, 10:21 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean54 min
Jul 17, 10:22 PM EDTTornado WarningPHIBurlington, Monmouth, Ocean23 min
Jul 17, 10:27 PM EDTSpecial Weather StatementPHIBurlington, Camden33 min
Jul 17, 10:38 PM EDTTornado WarningPHIBurlington, Monmouth, Ocean16 min
Jul 17, 10:43 PM EDTFlash Flood WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean79 min
Jul 17, 10:47 PM EDTSpecial Marine WarningPHI118 min
Jul 17, 10:51 PM EDTSpecial Marine WarningPHI114 min
Jul 17, 11:07 PM EDTSpecial Weather StatementPHIMiddlesex38 min
Jul 17, 11:08 PM EDTAreal Flood WarningPHIHunterdon12 hr
Jul 17, 11:11 PM EDTSpecial Weather StatementPHIMonmouth, Ocean34 min
Jul 17, 11:20 PM EDTSpecial Marine WarningPHI115 min
Jul 17, 11:26 PM EDTAreal Flood WarningPHISomerset10 hr
Jul 18, 2:41 AM EDTAreal Flood WarningPHIMercer4 hr
Jul 18, 3:48 AM EDTRiver Flood WarningPHIMercer3 hr
Jul 18, 9:08 AM EDTAreal Flood WarningPHISomerset2 hr
Jul 18, 11:03 AM EDTRiver Flood WarningPHIMiddlesex, Somerset88 min
Jul 17, 8:44 PM EDTAreal Flood AdvisoryPHIChester, Montgomery82 min
Jul 17, 8:57 PM EDTSevere Thunderstorm WarningPHIChester48 min
Jul 17, 9:15 PM EDTAreal Flood AdvisoryPHIDelaware, Montgomery, Philadelphia2 hr

Nearby

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