Alert archive / New Jersey / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 20, NWS Philadelphia/Mount Holly

May 15, 20184 counties in New Jersey; Delaware County, Philadelphia County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 15, 2018, 5:38 PM EDT for 4 counties in New Jersey; Delaware County, Philadelphia County, Pennsylvania; New Castle County, Delaware. It was in force for 67 min. 3 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 15, 2018, 5:38 PM EDT (21:38 UTC)
Expired: May 15, 2018, 6:45 PM EDT
In force: 67 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties New Castle County, DE, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Salem County, NJ, Delaware County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 89 km from the middle of the area, began a volume at 21:39 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
May 15, 6:01 PM EDT	TSTM WND GST 50	Larchmont, PA	CWOP STATION REPORTS WIND GUST OF 50 MPH
May 15, 6:01 PM EDT	TSTM WND GST 50	Newtown Square E, PA
May 15, 6:10 PM EDT	TSTM WND DMG	Philadelphia, PA	ACCORDING TO EM FIRE DEPT. RESPONDED TO 16 OUTSIDE DOWNED WIRE EVENTS AND ONE TREE FIRE. PHILADELPHIA 311 REPORTED 5 DOWNED TREES.

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.

Issued	Product	Office	Lasted
May 15, 1:46 PM EDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.6 hours before the alert went out and 198 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: 47 J/kg
Mixed-layer CIN: -484 J/kg
Mixed-layer LCL: 1259 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 117 m²/s²
0-3 km storm-relative helicity: 79 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

578 
WUUS51 KPHI 152138
SVRPHI
DEC003-NJC005-007-015-033-PAC045-101-152245-
/O.NEW.KPHI.SV.W.0020.180515T2138Z-180515T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
538 PM EDT TUE MAY 15 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...
  Northwestern Camden County in southern New Jersey...
  Northwestern Gloucester County in southern New Jersey...
  West central Burlington County in southern New Jersey...
  Southwestern Philadelphia County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 645 PM EDT.

* At 537 PM EDT, a severe thunderstorm was located over Yeadon, or
  near Camden, moving east at 55 mph.

  HAZARD...60 mph wind gusts and penny size hail. Strong winds 
           precede the heavy rains and thunder. 

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Philadelphia, Camden, Wilmington, Newark, Gloucester City, Cherry
  Hill, Mount Laurel, Chester, Deptford, West Deptford, Pennsville,
  Bellmawr, Yeadon, Woodbury, Carneys Point, Folcroft, Swarthmore,
  Elsmere, Paulsboro and New Castle.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3982 7568 3984 7560 3988 7559 3993 7554
      3998 7544 4000 7545 4003 7540 4002 7531
      3998 7527 4001 7521 3995 7481 3953 7551
      3972 7577
TIME...MOT...LOC 2137Z 290DEG 48KT 3995 7524 

HAIL...0.75IN
WIND...60MPH
 
$$

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The office that day

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

Issued	Product	Office	Counties	Lasted
May 15, 3:40 AM EDT	Flash Flood Watch	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 7 more	21 hr
May 15, 2:49 PM EDT	Special Weather Statement	PHI	Sussex, Warren	56 min
May 15, 3:46 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Morris, Sussex, Warren	74 min
May 15, 4:24 PM EDT	Special Weather Statement	PHI	Hunterdon, Somerset	51 min
May 15, 4:41 PM EDT	Severe Thunderstorm Warning	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset, Warren	64 min
May 15, 4:49 PM EDT	Special Marine Warning	PHI		86 min
May 15, 5:22 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	38 min
May 15, 5:31 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Morris, Somerset	3 hr
May 15, 5:35 PM EDT	Areal Flood Advisory	PHI	Hunterdon, Mercer, Middlesex, Somerset	4 hr
May 15, 5:53 PM EDT	Severe Thunderstorm Warning	PHI	Burlington, Mercer, Middlesex, Monmouth, Ocean	52 min
May 15, 6:02 PM EDT	Special Marine Warning	PHI		88 min
May 15, 6:10 PM EDT	Areal Flood Advisory	PHI	Burlington, Camden, Gloucester, Monmouth, Ocean, Salem	4 hr
May 15, 6:12 PM EDT	Special Marine Warning	PHI		63 min
May 15, 6:17 PM EDT	Special Weather Statement	PHI	Burlington, Camden, Cumberland, Gloucester, Ocean	43 min
May 15, 6:35 PM EDT	Severe Thunderstorm Warning	PHI	Salem	40 min
May 15, 6:46 PM EDT	Special Weather Statement	PHI	Atlantic, Cumberland, Ocean, Salem	74 min
May 15, 6:58 PM EDT	Areal Flood Advisory	PHI	Salem	4 hr
May 15, 7:14 PM EDT	Special Marine Warning	PHI		91 min
May 15, 7:18 PM EDT	Severe Thunderstorm Warning	PHI	Salem	57 min
May 15, 7:30 PM EDT	Special Marine Warning	PHI		90 min
May 15, 3:20 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	55 min
May 15, 4:12 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	33 min
May 15, 4:26 PM EDT	Tornado Warning	PHI	Berks, Bucks, Lehigh, Montgomery, Northampton	19 min
May 15, 5:12 PM EDT	Severe Thunderstorm Warning	PHI	Chester	63 min
May 15, 5:14 PM EDT	Areal Flood Advisory	PHI	Berks, Chester, Montgomery	2 hr
May 15, 6:15 PM EDT	Severe Thunderstorm Warning	PHI	Chester	60 min
May 14, 8:45 PM EDT	Special Weather Statement	PHI	Sussex	30 min

Nearby

Severe Thunderstorm Warnings in New Jersey, 2018 Severe Thunderstorm Warnings in Pennsylvania, 2018 Severe Thunderstorm Warnings in Delaware, 2018 Every 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.