Alert archive / New Jersey / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 5, NWS Philadelphia/Mount Holly

May 12, 2018Gloucester County, Salem County, New Jersey; Chester County, Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 12, 2018, 7:00 PM EDT for Gloucester County, Salem County, New Jersey; Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 45 min. 6 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
May 12, 2018, 7:00 PM EDT (23:00 UTC)
Expired
May 12, 2018, 7:45 PM EDT
In force
45 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Possible
Hail
1.0 in
Wind
60.0 mph

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

The radar

The Dover AFB radar (KDOX), 123 km from the middle of the area, began a volume at 23:02 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
May 12, 7:25 PM EDTHAIL 0.88Kemblesville, PA
May 12, 7:25 PM EDTHAIL 1West Grove, PAPHOTO OF QUARTER SIZED HAIL IN WEST GROVE. TIME ESTIMATED FROM RADAR.
May 12, 7:35 PM EDTHAIL 11 Ne Toughkenamon, PAMPING REPORT OF QUARTER SIZED HAIL.
May 12, 7:36 PM EDTHAIL 1Hockessin, DE
May 12, 7:37 PM EDTHAIL 0.75Concord Hills, DEDIME-SIZED HAIL ON ROUTE 202 NEAR NAAMANS ROAD.
May 12, 7:46 PM EDTHAIL 0.75Elsmere, DEHAIL UP TO PENNY SIZE IN ELSMERE. TIME APPROXIMATED FROM RADAR.

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
May 12, 4:58 PM EDTTornado WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.0 hours before the alert went out and 164 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 2018-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2018-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 178 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1390 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
178 m²/s²
0-3 km storm-relative helicity
201 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

207 
WUUS51 KPHI 122300
SVRPHI
DEC003-NJC015-033-PAC029-045-122345-
/O.NEW.KPHI.SV.W.0005.180512T2300Z-180512T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
700 PM EDT SAT MAY 12 2018

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...
  West central Gloucester County in southern New Jersey...
  Southern Chester County in southeastern Pennsylvania...
  Southwestern Delaware County in southeastern Pennsylvania...

* Until 745 PM EDT.

* At 658 PM EDT, a severe thunderstorm was located near Paradise, or
  9 miles east of Willow Street, moving east at 40 mph.

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

  SOURCE...Trained weather spotters reported nickel sized hail in 
           York Pennsylvania.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Wilmington, West Chester, Chester, Pennsville, Coatesville,
  Westtown, Carneys Point, Downingtown, Swarthmore, Elsmere, Kennett
  Square, New Castle, Penns Grove, Oxford, Parkesburg, West Grove,
  Newport, Arden, Stanton and Cheyney.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

&&

A tornado watch remains in effect until 100 AM EDT for northern
Delaware...southern New Jersey...and southeastern Pennsylvania.

LAT...LON 3983 7602 3985 7602 3987 7600 3987 7599
      3992 7600 3994 7598 3995 7600 4003 7595
      3998 7534 3965 7541 3980 7604 3983 7604
TIME...MOT...LOC 2258Z 280DEG 38KT 3995 7611 

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

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 6:26 AM EDTSpecial Weather StatementPHIAtlantic49 min
May 12, 7:02 AM EDTSpecial Marine WarningPHI58 min
May 12, 6:53 PM EDTSpecial Weather StatementPHIMercer52 min
May 12, 7:16 PM EDTSevere Thunderstorm WarningPHISalem44 min
May 12, 7:30 PM EDTSevere Thunderstorm WarningPHIGloucester, Salem45 min
May 12, 7:37 PM EDTAreal Flood AdvisoryPHIBurlington, Camden, Mercer, Monmouth, Ocean2 hr
May 12, 7:45 PM EDTSevere Thunderstorm WarningPHIAtlantic, Camden, Cumberland, Gloucester, Salem45 min
May 12, 7:48 PM EDTSpecial Marine WarningPHI57 min
May 12, 6:51 PM EDTSpecial Weather StatementPHIChester39 min
May 12, 7:10 PM EDTAreal Flood AdvisoryPHIChester, Delaware2 hr
May 12, 7:25 PM EDTSevere Thunderstorm WarningPHIKent, New Castle50 min
May 12, 7:57 PM EDTAreal Flood AdvisoryPHIKent, New Castle4 hr

Nearby

Severe Thunderstorm Warnings in New Jersey, 2018Severe Thunderstorm Warnings in Pennsylvania, 2018Severe Thunderstorm Warnings in Delaware, 2018Every severe thunderstorm warning in 2018

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.