Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 60, NWS Philadelphia/Mount Holly

June 23, 2015Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 23, 2015, 5:28 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware; Cecil County, Maryland. It was in force for 47 min. 14 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 23, 2015, 5:28 PM EDT (21:28 UTC)
Expired
Jun 23, 2015, 6:15 PM EDT
In force
47 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties New Castle County, DE, Cecil County, MD, Chester County, PA, Delaware County, PA

The radar

The Dover AFB radar (KDOX), 107 km from the middle of the area, began a volume at 21:31 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
Jun 23, 5:28 PM EDTTSTM WND DMGRising Sun, MDTREES REPORTED DOWN.
Jun 23, 5:35 PM EDTTSTM WND DMGHockessin, DETREES AND WIRES DOWN
Jun 23, 5:37 PM EDTTSTM WND DMGGlen Mills, PATREE DOWN ON A HOUSE
Jun 23, 5:39 PM EDTTSTM WND DMGPike Creek, DETREES AND WIRES DOWN
Jun 23, 5:41 PM EDTTSTM WND DMGNewark, DETREES AND WIRES DOWN
Jun 23, 5:42 PM EDTTSTM WND DMGGreenville, DETREES AND WIRES DOWN
Jun 23, 5:45 PM EDTTSTM WND DMGAston Twp, PAMULTIPLE TREES REPORTED DOWN. SEVERAL OTHERS APPEAR TO HAVE BEEN SHEARED OFF AT THE TOP.
Jun 23, 5:45 PM EDTTSTM WND DMGWilmington, DEROOF BLOWN OFF THIRD STORY BUILDING
Jun 23, 5:45 PM EDTTSTM WND GST 62Talleyville, DE
Jun 23, 5:45 PM EDTTSTM WND GST 66New Castle County Airpo, DEA 66 MPH WIND GUST WAS MEASURED AT THE NEW CASTLE COUNTY AIRPORT.
Jun 23, 5:45 PM EDTTSTM WND GST 66New Castle County Airpo, DEA 66 MPH WIND GUST WAS MEASURED AT THE NEW CASTLE COUNTY AIRPORT. IN ADDITION... A SUSTAINED WIND OF 53 MPH WAS MEASURED AT 546 PM.
Jun 23, 5:45 PM EDTTSTM WND GST 67New Castle County Airpo, DE
Jun 23, 5:48 PM EDTTSTM WND DMGUpland, PAOVER 70 TREES REPORTED DOWN IN UPLAND PARK.
Jun 23, 5:50 PM EDTTSTM WND DMGMinquadale, DEMULTIPLE TREES DOWN WITH SOME FALLING ONTO HOUSES.

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
Jun 23, 10:20 AM EDTSevere Thunderstorm WatchSPC7 hr
Jun 23, 4:09 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.5 hours before the alert went out and 167 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 2015-06-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 387 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 2015-06-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 121 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
387 J/kg
Mixed-layer CIN
-168 J/kg
Mixed-layer LCL
1544 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
121 m²/s²
0-3 km storm-relative helicity
24 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

632 
WUUS51 KPHI 232128
SVRPHI
DEC003-MDC015-PAC029-045-232215-
/O.NEW.KPHI.SV.W.0060.150623T2128Z-150623T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
528 PM EDT TUE JUN 23 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  WEST CENTRAL CECIL COUNTY IN NORTHEASTERN MARYLAND...
  SOUTHWESTERN DELAWARE COUNTY IN SOUTHEASTERN PENNSYLVANIA...
  SOUTHERN CHESTER COUNTY IN SOUTHEASTERN PENNSYLVANIA...

* UNTIL 615 PM EDT

* AT 527 PM EDT...DOPPLER RADAR INDICATED A LINE OF SEVERE
  THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60
  MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM
  COCHRANVILLE TO OXFORD TO RICHARDSMERE...AND MOVING EAST AT 40 MPH.

* LOCATIONS IMPACTED INCLUDE...
  WILMINGTON...NEWARK...CALVERT...WESTTOWN...ELSMERE...KENNETT
  SQUARE...NEW CASTLE...OXFORD...NORTH EAST...WEST GROVE...RISING
  SUN...NEWPORT...ARDEN...PLEASANT HILL...WOODLAWN...LADENBERG...
  ELAM...NORTH STAR...CHERRY HILL AND BAY VIEW.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...LARGE HAIL...DEADLY
LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

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.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THESE STORMS...AND MAY
LEAD TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

&&

LAT...LON 3989 7590 3995 7539 3981 7542 3971 7550
      3972 7552 3968 7555 3959 7612 3963 7615
      3966 7617
TIME...MOT...LOC 2127Z 262DEG 37KT 3988 7592 3979 7598 3971 7610 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 23, 8:30 AM EDTSpecial Weather StatementPHIMonroe60 min
Jun 23, 9:10 AM EDTSpecial Weather StatementPHIMonroe35 min
Jun 23, 10:37 AM EDTSpecial Weather StatementPHICarbon, Monroe38 min
Jun 23, 11:13 AM EDTSpecial Weather StatementPHIMonroe32 min
Jun 23, 1:31 PM EDTSpecial Weather StatementPHICarbon, Monroe, Northampton59 min
Jun 23, 1:41 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe49 min
Jun 23, 2:29 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton46 min
Jun 23, 3:49 PM EDTSpecial Weather StatementPHIBerks, Bucks, Chester, Montgomery86 min
Jun 23, 4:11 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh24 min
Jun 23, 4:44 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery61 min
Jun 23, 5:05 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Delaware, Montgomery40 min
Jun 23, 5:19 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery4 hr
Jun 23, 5:22 PM EDTTornado WarningPHIChester23 min
Jun 23, 5:38 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia52 min
Jun 23, 5:44 PM EDTAreal Flood AdvisoryPHIChester, Delaware, Montgomery, Philadelphia4 hr
Jun 23, 6:18 PM EDTAreal Flood AdvisoryPHIMonroe, Northampton4 hr
Jun 23, 6:14 PM EDTAreal Flood AdvisoryPHIKent, New Castle4 hr
Jun 23, 6:44 PM EDTSevere Thunderstorm WarningPHIKent76 min
Jun 23, 6:48 PM EDTAreal Flood AdvisoryPHIKent4 hr
Jun 23, 7:41 PM EDTSevere Thunderstorm WarningPHIKent, Sussex65 min
Jun 23, 7:06 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot84 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2015Severe Thunderstorm Warnings in Delaware, 2015Severe Thunderstorm Warnings in Maryland, 2015Every severe thunderstorm warning in 2015

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.