Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 31, NWS Philadelphia/Mount Holly

May 12, 2002Berks County, Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 12, 2002, 5:42 PM EDT for Berks County, Chester County, Pennsylvania. It was in force for 33 min. 3 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
May 12, 2002, 5:42 PM EDT (21:42 UTC)
Expired
May 12, 2002, 6:15 PM EDT
In force
33 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Berks County, PA, Chester County, PA

The radar

The Philadelphia radar (KDIX), 124 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
May 12, 5:55 PM EDTThunderstorm Wind 56 ESpring City, PA
May 12, 6:10 PM EDTThunderstorm Wind 50 ELudwigs Corner, PA
May 12, 6:15 PM EDTThunderstorm Wind 52 MWest Chester, PA

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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 12, 3:30 PM EDTSevere Thunderstorm WatchSPC6 hr
May 12, 5:15 PM EDTSevere Thunderstorm WatchSPC5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.7 hours before the alert went out and 193 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 2002-05-12Temperature 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 2002-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 150 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
1104 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
150 m²/s²
0-3 km storm-relative helicity
143 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 122142 CCA
SVRPHI
PAC011-029-122215-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING - CORRECTED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
539 PM EDT SUN MAY 12 2002

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 615 PM EDT.

* AT 538 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM... 3 MILES NORTHWEST OF ELVERSON...MOVING EAST
  AT 45 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  LIONVILLE AT 555 PM.
  PHOENIXVILLE AT 600 PM.
  PAOLI AT 605 PM.

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

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 PM SUNDAY 
EVENING FOR THE AREA.

THESE STORMS HAVE HAD A HISTORY OF PRODUCING STRONG WINDS WHILE 
MOVING THROUGH CENTRAL PENNSYLVANIA.

$$

LAT...LON 4026 7573 4010 7595 3996 7554 4008 7541
          4020 7559

JWH

...CORRECTION TO REMOVE BERKS COUNTY FROM THE WARNING...

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 5:15 PM EDTSevere Thunderstorm WarningPHIBerks30 min
May 12, 5:40 PM EDTSevere Thunderstorm WarningPHIBerks, Chester35 min
May 12, 6:19 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Philadelphia26 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 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.