Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 60, NWS Philadelphia/Mount Holly

June 21, 20175 counties in Pennsylvania; Burlington County, Camden County, Gloucester County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 21, 2017, 4:28 PM EDT for 5 counties in Pennsylvania; Burlington County, Camden County, Gloucester County, New Jersey. It was in force for 47 min. 17 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: Jun 21, 2017, 4:28 PM EDT (20:28 UTC)
Expired: Jun 21, 2017, 5:15 PM EDT
In force: 47 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 57 km from the middle of the area, began a volume at 20:28 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
Jun 21, 4:32 PM EDT	TSTM WND DMG	Lower Merion Twp, PA	SEVERAL WINDS AND TREES BLOWN DOWN
Jun 21, 4:33 PM EDT	TSTM WND GST 72	3 N Conshohocken, PA	TIME ESTIMATED
Jun 21, 4:35 PM EDT	TSTM WND DMG	Radnor, PA	NUMEROUS LARGE TREES DOWN... TIME ESTIMATED
Jun 21, 4:42 PM EDT	TSTM WND DMG	Warminster Heights, PA	LARGE TREE LIMBS DOWN
Jun 21, 4:45 PM EDT	TSTM WND DMG	Mayfair, PA	TREES DOWN... TIME ESTIMATED
Jun 21, 4:46 PM EDT	TSTM WND GST 65	Fishtown, PA
Jun 21, 4:50 PM EDT	TSTM WND DMG	Collingswood, NJ	LARGE BRANCH DOWN ON SOME WIRES... TIME ESTIMATED
Jun 21, 4:53 PM EDT	TSTM WND DMG	Cinnaminson, NJ	TREE DOWN... TIME ESTIMATED
Jun 21, 4:54 PM EDT	TSTM WND DMG	Riverside, NJ	LARGE TREE LIMB SNAPPED... TIME ESTIMATED
Jun 21, 4:56 PM EDT	TSTM WND DMG	Pennsauken, NJ	LARGE BRANCH DOWN... TIME ESTIMATED
Jun 21, 4:58 PM EDT	TSTM WND DMG	South Philadelphia, PA	LARGE TREE DOWN... TIME ESTIMATED
Jun 21, 4:59 PM EDT	TSTM WND DMG	Delanco, NJ	SEVERAL TREES DOWN... TIME ESTIMATED
Jun 21, 5:00 PM EDT	TSTM WND DMG	Moorestown, NJ	TREES AND WIRES DOWN... TIME ESTIMATED
Jun 21, 5:02 PM EDT	TSTM WND DMG	Mount Laurel, NJ	TREES DOWN ON MOUNT LAUREL RD... TIME ESTIMATED
Jun 21, 5:05 PM EDT	TSTM WND DMG	Delran Twp, NJ	SEVERAL LARGE TREE LIMBS DOWN... TIME ESTIMATED
Jun 21, 5:05 PM EDT	TSTM WND DMG	Delran Twp, NJ	SEVERAL LARGE TREES DOWN... TIME ESTIMATED
Jun 21, 5:08 PM EDT	TSTM WND DMG	Mount Holly Wfo, NJ	MOUNT HOLLY TWP... SEVERAL TREES DOWN... TIME ESTIMATED

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 8.5 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.

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: 23 J/kg
Mixed-layer CIN: -90 J/kg
Mixed-layer LCL: 1706 m above ground
0-6 km bulk shear: 67 kt
0-1 km storm-relative helicity: -3 m²/s²
0-3 km storm-relative helicity: 97 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

179 
WUUS51 KPHI 212028
SVRPHI
NJC005-007-015-PAC017-029-045-091-101-212115-
/O.NEW.KPHI.SV.W.0060.170621T2028Z-170621T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
428 PM EDT WED JUN 21 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Camden County in southern New Jersey...
  North central Gloucester County in southern New Jersey...
  Northwestern Burlington County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  South central Bucks County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 515 PM EDT

* At 426 PM EDT, severe thunderstorms were located along a line
  extending from Fricks to near East Norriton to King Of Prussia,
  moving southeast at 35 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Train spotter and radar indicated. Numerous downed trees 
           and wires were reported as these storms moved through 
           Pottstown and Green Lane area.

  IMPACT...Expect damage to trees and power lines. 

* Locations impacted include...
  Philadelphia, Camden, Gloucester City, Cherry Hill, Bensalem, Mount
  Laurel, Norristown, Willingboro, East Norriton, Bellmawr, Yeadon,
  Woodbury, Burlington, Bristol, Riverside, Conshohocken, Palmyra,
  Hatboro, Ambler and Jenkintown.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

LAT...LON 4008 7475 3994 7485 3980 7510 4003 7548
      4012 7533 4025 7519
TIME...MOT...LOC 2026Z 301DEG 31KT 4030 7523 4017 7530 4007 7539 

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

JRK

2 follow-up statements

026 
WWUS51 KPHI 212051
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
451 PM EDT WED JUN 21 2017

PAC029-212057-
/O.CAN.KPHI.SV.W.0060.000000T0000Z-170621T2115Z/
Chester PA-
451 PM EDT WED JUN 21 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3997 7539 4004 7523 4022 7511 4008 7475
      3994 7485 3980 7510
TIME...MOT...LOC 2047Z 305DEG 33KT 4019 7504 3999 7510 3996 7530 

$$

NJC005-007-015-PAC017-045-091-101-212115-
/O.CON.KPHI.SV.W.0060.000000T0000Z-170621T2115Z/
Camden NJ-Gloucester NJ-Burlington NJ-Montgomery PA-Bucks PA-
Philadelphia PA-Delaware PA-
451 PM EDT WED JUN 21 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR NORTHWESTERN CAMDEN...NORTH CENTRAL GLOUCESTER...NORTHWESTERN
BURLINGTON...SOUTHEASTERN MONTGOMERY...SOUTH CENTRAL BUCKS...
PHILADELPHIA AND EAST CENTRAL DELAWARE COUNTIES...

At 447 PM EDT, severe thunderstorms were located along a line
extending from near Ivyland to Kensington to Drexel Hill, moving
southeast at 40 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Trained spotter indicated. Numerous downed trees and wires 
         have been reported in Pottstown, Green Lane and Franconia 
         in Montgomery County between 400 and 415 PM. Additional 
         downed trees were reported in Radnor Township in northern 
         Delaware county around 430 PM.

IMPACT...Expect damage to trees and power lines. 

Locations impacted include...
Philadelphia, Camden, Gloucester City, Cherry Hill, Bensalem, Mount
Laurel, Willingboro, Bellmawr, Yeadon, Woodbury, Burlington, Bristol,
Riverside, Palmyra, Hatboro, Jenkintown, Magnolia, Westville,
Narberth and National Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3997 7539 4004 7523 4022 7511 4008 7475
      3994 7485 3980 7510
TIME...MOT...LOC 2047Z 305DEG 33KT 4019 7504 3999 7510 3996 7530 

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

JRK

360 
WWUS51 KPHI 212107
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
507 PM EDT WED JUN 21 2017

PAC045-091-101-212117-
/O.CAN.KPHI.SV.W.0060.000000T0000Z-170621T2115Z/
Montgomery PA-Philadelphia PA-Delaware PA-
507 PM EDT WED JUN 21 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN MONTGOMERY...
PHILADELPHIA AND EAST CENTRAL DELAWARE COUNTIES IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3983 7515 3988 7519 3988 7515 3990 7513
      3993 7511 4001 7498 4014 7491 4008 7475
      3994 7485 3980 7510
TIME...MOT...LOC 2107Z 301DEG 31KT 4011 7487 3991 7493 3988 7513 

$$

NJC005-007-015-PAC017-212115-
/O.CON.KPHI.SV.W.0060.000000T0000Z-170621T2115Z/
Camden NJ-Gloucester NJ-Burlington NJ-Bucks PA-
507 PM EDT WED JUN 21 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR NORTHWESTERN CAMDEN...NORTH CENTRAL GLOUCESTER...NORTHWESTERN
BURLINGTON AND SOUTHERN BUCKS COUNTIES...

At 507 PM EDT, severe thunderstorms were located along a line
extending from Bristol to Marlton to Brooklawn, moving southeast at
35 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Trained weather spotters. Numerous downed trees and wires 
         have been reported in Pottstown, Green Lane and Franconia 
         Montgomery County between 400 and 415 PM. Additional downed 
         trees were reported in Radnor Township in northern Delaware 
         county around 435 PM.

IMPACT...Expect damage to trees and power lines. 

Locations impacted include...
Camden, Gloucester City, Cherry Hill, Mount Laurel, Willingboro,
Bellmawr, Woodbury, Burlington, Bristol, Riverside, Magnolia,
Westville, National Park, Beverly, Brooklawn, Audubon Park,
Barclay-Kingston, Cherry Hill Mall, Golden Triangle and Marlton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm has a history of producing wind damage. For your 
protection move to an interior room on the lowest floor of a 
building.

&&

LAT...LON 3983 7515 3988 7519 3988 7515 3990 7513
      3993 7511 4001 7498 4014 7491 4008 7475
      3994 7485 3980 7510
TIME...MOT...LOC 2107Z 301DEG 31KT 4011 7487 3991 7493 3988 7513 

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

JRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 21, 2:32 PM EDT	Special Weather Statement	PHI	Carbon	43 min
Jun 21, 3:32 PM EDT	Special Weather Statement	PHI	Carbon, Northampton	28 min
Jun 21, 3:51 PM EDT	Special Weather Statement	PHI	Montgomery	39 min
Jun 21, 4:02 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Montgomery	43 min
Jun 21, 4:21 PM EDT	Special Weather Statement	PHI	Bucks	39 min
Jun 21, 5:28 PM EDT	Special Weather Statement	PHI	Chester, Delaware	32 min
Jun 21, 5:03 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Gloucester, Ocean	42 min
Jun 21, 5:19 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Monmouth, Ocean	41 min
Jun 21, 5:36 PM EDT	Special Marine Warning	PHI		84 min
Jun 21, 5:38 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Ocean	37 min
Jun 21, 5:54 PM EDT	Severe Thunderstorm Warning	PHI	Monmouth, Ocean	26 min
Jun 21, 6:03 PM EDT	Special Marine Warning	PHI		42 min
Jun 21, 6:25 PM EDT	Special Marine Warning	PHI		95 min
Jun 21, 6:27 PM EDT	Special Weather Statement	PHI	Cumberland, Salem	33 min
Jun 21, 6:31 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cumberland, Gloucester, Salem	44 min
Jun 21, 6:52 PM EDT	Special Marine Warning	PHI		53 min
Jun 21, 6:57 PM EDT	Severe Thunderstorm Warning	PHI	Cumberland	48 min
Jun 21, 7:05 PM EDT	Special Weather Statement	PHI	Cape May	25 min
Jun 21, 7:11 PM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cape May, Cumberland	64 min
Jun 21, 7:17 PM EDT	Special Marine Warning	PHI		88 min
Jun 21, 7:56 PM EDT	Special Marine Warning	PHI		94 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2017 Severe Thunderstorm Warnings in New Jersey, 2017 Every severe thunderstorm warning in 2017

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.