Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 191, NWS Philadelphia/Mount Holly

August 24, 2002Chester County, Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 24, 2002, 7:42 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 33 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Aug 24, 2002, 7:42 PM EDT (23:42 UTC)
Expired
Aug 24, 2002, 8:15 PM EDT
In force
33 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

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

The radar

The Philadelphia radar (KDIX), 102 km from the middle of the area, began a volume at 23:43 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 24, 7:45 PM EDTThunderstorm Wind 52 ECountywide, PA
Aug 24, 8:02 PM EDTThunderstorm Wind 52 EClaymont, DE

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 11.7 hours before the alert went out and 183 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 2002-08-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 639 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 2002-08-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 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
639 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
611 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
94 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.2

Open this sounding in Storm Lab

The text

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

475 
WUUS51 KPHI 242342
SVRPHI
DEC003-PAC029-045-250015-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
742 PM EDT SAT AUG 24 2002

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE.
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA.
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA.

* UNTIL 815 PM EDT.

* AT 733 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM... ALONG A LINE EXTENDING FROM 6 MILES NORTH OF
  LIONVILLE TO 4 MILES NORTHWEST OF KENNETT SQUARE TO 7 MILES
  SOUTHWEST OF OXFORD...MOVING SOUTHEAST AT 35 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  TALLEYVILLE AT 750 PM.
  RADNOR TOWNSHIP...LIMA...STANTON AT 755 PM.
  NETHER PROVIDENCE TOWNSHIP...BROOMALL...WILMINGTON...NEWPORT AT 800
  PM.
  SWARTHMORE...DREXEL HILL AT 805 PM.

FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER
RADIO...YOUR LOCAL RADIO OR TELEVISION STATION...OR YOUR CABLE
TELEVISION OUTLET.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 24, 7:06 PM EDTSevere Thunderstorm WarningPHIPhiladelphia24 min
Aug 24, 7:12 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery33 min
Aug 24, 7:44 PM EDTSevere Thunderstorm WarningPHIMontgomery, Philadelphia46 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2002Severe Thunderstorm Warnings in Delaware, 2002Every severe thunderstorm warning in 2002

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.