Alert archive / New Jersey / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 167, NWS Philadelphia/Mount Holly

August 18, 20174 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 18, 2017, 5:39 PM EDT for 4 states. It was in force for 66 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
Aug 18, 2017, 5:39 PM EDT (21:39 UTC)
Expired
Aug 18, 2017, 6:45 PM EDT
In force
66 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties New Castle County, DE, Cecil County, MD, Kent County, MD, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Chester County, PA, Delaware County, PA, Philadelphia County, PA

The radar

The Dover AFB radar (KDOX), 94 km from the middle of the area, began a volume at 21:43 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
Aug 18, 5:40 PM EDTTSTM WND DMGNew Garden, PASEVERAL TREES DOWN.

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
Aug 18, 2:27 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.7 hours before the alert went out and 162 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 2017-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 746 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 2017-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 12 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
746 J/kg
Mixed-layer CIN
-72 J/kg
Mixed-layer LCL
651 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
12 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

957 
WUUS51 KPHI 182139
SVRPHI
DEC003-MDC015-029-NJC005-007-015-033-PAC029-045-101-182245-
/O.NEW.KPHI.SV.W.0167.170818T2139Z-170818T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
539 PM EDT FRI AUG 18 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  New Castle County in northern Delaware...
  Northern Kent County in northeastern Maryland...
  Cecil County in northeastern Maryland...
  Northwestern Salem County in southern New Jersey...
  Northwestern Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  Northwestern Burlington County in southern New Jersey...
  Southeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 645 PM EDT

* At 539 PM EDT, severe thunderstorms were located along a line
  extending from near Kennett Square to Back River, moving east at 30
  mph.

  HAZARD...60 mph wind gusts and quarter size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Minor damage to vehicles is possible. Expect damage to 
           trees and power lines. 

* Locations impacted include...
  Philadelphia, Camden, Wilmington, Newark, Middletown, West Chester,
  Elkton, Havre De Grace, Gloucester City, Calvert, Chester,
  Willingboro, Deptford, West Deptford, Pennsville, Bellmawr, Yeadon,
  Westtown, Woodbury and Burlington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather, contact your nearest law enforcement
agency. They will send your report to the National Weather Service
office in Mount Holly NJ.

In addition to large hail and damaging winds...frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember...if you can hear thunder...you are close
enough to be struck by lightning.

&&

LAT...LON 3929 7617 3932 7618 3933 7614 3937 7611
      3937 7606 3943 7600 3952 7598 3955 7603
      3955 7608 3962 7615 3993 7582 4001 7530
      3998 7527 4001 7521 4003 7522 4006 7498
      4005 7497 4010 7475 3926 7580 3923 7623
TIME...MOT...LOC 2139Z 258DEG 28KT 3988 7565 3928 7644 

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

SFJ
2 follow-up statements
636 
WWUS51 KPHI 182205
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
605 PM EDT FRI AUG 18 2017

DEC003-MDC015-029-NJC005-007-015-033-PAC029-045-101-182245-
/O.CON.KPHI.SV.W.0167.000000T0000Z-170818T2245Z/
New Castle DE-Kent MD-Cecil MD-Salem NJ-Camden NJ-Gloucester NJ-
Burlington NJ-Chester PA-Philadelphia PA-Delaware PA-
605 PM EDT FRI AUG 18 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR NEW CASTLE...NORTHERN KENT...CECIL...NORTHWESTERN SALEM...
NORTHWESTERN CAMDEN...NORTHWESTERN GLOUCESTER...NORTHWESTERN
BURLINGTON...SOUTHEASTERN CHESTER...PHILADELPHIA AND DELAWARE
COUNTIES...

At 605 PM EDT, severe thunderstorms were located along a line
extending from near Lima to near Newtown, moving east at 30 mph.

HAZARD...60 mph wind gusts and quarter size hail. 

SOURCE...Radar indicated. 

IMPACT...Minor damage to vehicles is possible. Expect damage to 
         trees and power lines. 

Locations impacted include...
Philadelphia, Camden, Wilmington, Newark, Middletown, West Chester,
Elkton, Gloucester City, Calvert, Chester, Willingboro, Deptford,
West Deptford, Pennsville, Bellmawr, Yeadon, Westtown, Woodbury,
Burlington and Riverside.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

In addition to large hail and damaging winds...frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember...if you can hear thunder...you are close
enough to be struck by lightning.

&&

LAT...LON 3929 7617 3932 7618 3937 7611 3937 7606
      3943 7600 3952 7598 3955 7608 3960 7611
      3994 7571 4001 7530 3998 7527 4001 7521
      4003 7522 4005 7497 4010 7475 3926 7580
      3923 7623
TIME...MOT...LOC 2205Z 258DEG 28KT 3992 7540 3932 7619 

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

SFJ
549 
WWUS51 KPHI 182239
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
639 PM EDT FRI AUG 18 2017

DEC003-MDC015-029-NJC005-007-015-033-PAC029-045-101-182249-
/O.EXP.KPHI.SV.W.0167.000000T0000Z-170818T2245Z/
New Castle DE-Kent MD-Cecil MD-Salem NJ-Camden NJ-Gloucester NJ-
Burlington NJ-Chester PA-Philadelphia PA-Delaware PA-
639 PM EDT FRI AUG 18 2017

...THE SEVERE THUNDERSTORM WARNING FOR NEW CASTLE...KENT...CECIL...
NORTHWESTERN SALEM...NORTHWESTERN CAMDEN...NORTHWESTERN GLOUCESTER...
NORTHWESTERN BURLINGTON...SOUTHEASTERN CHESTER...PHILADELPHIA AND
DELAWARE COUNTIES WILL EXPIRE AT 645 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
and heavy rain are still possible with these thunderstorms.

A severe thunderstorm watch remains in effect until 900 PM EDT for
central and northern Delaware...northeastern Maryland...southern New
Jersey...and southeastern Pennsylvania.

LAT...LON 3929 7617 3932 7618 3937 7611 3937 7606
      3943 7600 3952 7598 3955 7608 3960 7611
      3994 7571 4001 7530 3998 7527 4001 7521
      4003 7522 4005 7497 4010 7475 3926 7580
      3923 7623
TIME...MOT...LOC 2239Z 258DEG 28KT 3997 7509 3937 7589 

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 3:39 AM EDTFlash Flood WatchPHICaroline, Cecil, Kent, Queen Anne's, Talbot18 hr
Aug 18, 4:29 PM EDTSevere Thunderstorm WarningPHICecil61 min
Aug 18, 4:57 PM EDTAreal Flood AdvisoryPHICecil3 hr
Aug 18, 5:03 PM EDTSevere Thunderstorm WarningPHICecil, Kent42 min
Aug 18, 6:10 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot65 min
Aug 18, 6:12 PM EDTAreal Flood AdvisoryPHICecil, Kent, Queen Anne's3 hr
Aug 18, 7:07 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot53 min
Aug 18, 7:33 PM EDTAreal Flood AdvisoryPHICaroline, Talbot3 hr
Aug 18, 7:53 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot48 min
Aug 18, 3:41 AM EDTSmall Craft AdvisoryPHI18 hr
Aug 18, 10:51 AM EDTSpecial Weather StatementPHIOcean54 min
Aug 18, 11:19 AM EDTAreal Flood AdvisoryPHIBurlington, Ocean116 min
Aug 18, 11:28 AM EDTSpecial Weather StatementPHIOcean47 min
Aug 18, 5:08 PM EDTSpecial Weather StatementPHIHunterdon, Warren37 min
Aug 18, 5:11 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer, Somerset49 min
Aug 18, 5:20 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Gloucester, Mercer, Salem3 hr
Aug 18, 5:42 PM EDTSpecial Weather StatementPHIHunterdon33 min
Aug 18, 5:46 PM EDTSevere Thunderstorm WarningPHIHunterdon, Morris, Somerset44 min
Aug 18, 5:50 PM EDTSpecial Marine WarningPHI55 min
Aug 18, 5:54 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth66 min
Aug 18, 6:13 PM EDTSpecial Weather StatementPHIMiddlesex, Somerset32 min
Aug 18, 6:20 PM EDTAreal Flood AdvisoryPHIMiddlesex, Somerset3 hr
Aug 18, 6:23 PM EDTSpecial Weather StatementPHISomerset37 min
Aug 18, 6:38 PM EDTSpecial Weather StatementPHICamden, Gloucester, Salem37 min
Aug 18, 6:41 PM EDTSpecial Marine WarningPHI64 min
Aug 18, 6:43 PM EDTAreal Flood AdvisoryPHIMonmouth, Ocean3 hr
Aug 18, 6:48 PM EDTSpecial Weather StatementPHICumberland, Gloucester, Salem27 min
Aug 18, 6:53 PM EDTSpecial Weather StatementPHIMiddlesex, Monmouth52 min
Aug 18, 6:54 PM EDTSpecial Weather StatementPHIBurlington, Camden, Gloucester51 min
Aug 18, 6:58 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Ocean29 min
Aug 18, 7:00 PM EDTSevere Thunderstorm WarningPHIBurlington, Mercer, Middlesex, Monmouth, Ocean60 min
Aug 18, 7:19 PM EDTAreal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Cumberland, Ocean, Salem3 hr
Aug 18, 7:25 PM EDTSpecial Weather StatementPHIAtlantic50 min
Aug 18, 7:34 PM EDTSpecial Weather StatementPHICape May26 min
Aug 18, 7:39 PM EDTSpecial Marine WarningPHI66 min
Aug 18, 7:43 PM EDTSpecial Weather StatementPHIBurlington, Ocean47 min
Aug 18, 7:44 PM EDTSpecial Marine WarningPHI61 min
Aug 18, 7:49 PM EDTSevere Thunderstorm WarningPHIAtlantic, Cape May, Cumberland, Gloucester35 min
Aug 18, 4:48 AM EDTAreal Flood AdvisoryPHIBerks, Lehigh, Northampton4 hr
Aug 18, 2:10 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh4 hr
Aug 18, 2:21 PM EDTSpecial Weather StatementPHIBerks24 min
Aug 18, 2:33 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh42 min
Aug 18, 3:14 PM EDTSpecial Weather StatementPHIBerks, Lehigh31 min
Aug 18, 3:15 PM EDTAreal Flood AdvisoryPHIBerks4 hr
Aug 18, 3:19 PM EDTSpecial Weather StatementPHINorthampton26 min
Aug 18, 3:37 PM EDTSpecial Weather StatementPHICarbon38 min
Aug 18, 3:43 PM EDTSpecial Weather StatementPHIBerks32 min
Aug 18, 3:45 PM EDTAreal Flood AdvisoryPHICarbon, Lehigh, Monroe, Northampton4 hr
Aug 18, 3:46 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Montgomery, Northampton44 min
Aug 18, 4:02 PM EDTFlash Flood WarningPHIBerks4 hr
Aug 18, 4:24 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Montgomery51 min
Aug 18, 6:20 PM EDTSpecial Weather StatementPHISussex25 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2017Severe Thunderstorm Warnings in Pennsylvania, 2017Severe Thunderstorm Warnings in Maryland, 2017Every 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.