Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1996

Severe Thunderstorm Warning 35, NWS Philadelphia/Mount Holly

June 11, 1996Chester County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 11, 1996, 2:55 PM EDT for Chester County, Pennsylvania; New Castle County, Delaware. It was in force for 60 min. 1 report 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
Jun 11, 1996, 2:55 PM EDT (18:55 UTC)
Expired
Jun 11, 1996, 3:55 PM EDT
In force
60 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties New Castle County, DE, Chester County, PA

The radar

The Dover AFB radar (KDOX), 108 km from the middle of the area, began a volume at 18:58 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 11, 3:30 PM EDTThunderstorm WindCoatesville, 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 nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.9 hours before the alert went out and 49 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, Phillips Aaf/Abe, MD at 12:00Z on 1996-06-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1123 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, Phillips Aaf/Abe, MD at 12:00Z on 1996-06-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
1123 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
805 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
-0.1
Supercell composite
-0.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 111855
SVRPHL
DEC003-PAC029-111955-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
255 PM EDT TUE JUN 11 1996

THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY NJ HAS
ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 355 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN  PENNSYLVANIA

   ...CHESTER COUNTY

IN  DELAWARE

   ...NEW CASTLE COUNTY
 
AT 252 PM EDT...A DEVELOPING SEVERE THUNDERSTORM WAS INDICATED BY NWS
DOPPLER RADAR ALONG THE CHESTER/CECIL COUNTY LINE...4 MILES SOUTHEAST
OF KEMBLESVILLE MOVING NORTHEAST AT 20 MPH.

THIS STORM MAY AFFECT THE FOLLOWING NEARBY AREAS... WEST GROVE...
HOCKESSIN AND AVONDALE.

STAY TUNED TO NOAA WEATHER RADIO...THE VOICE OF THE NATIONAL WEATHER
SERVICE...OR TO COMMERCIAL RADIO OR TELEVISION STATIONS FOR THE
LATEST STORM INFORMATION.

IF YOU SEE SEVERE WEATHER OR FLOODING...CONTACT YOUR LOCAL LAW
ENFORCEMENT AGEpNCY AND HAVE THEM RELAY YOUR SEVERE WEATHER REPORT ON
TO THE NATIONAL WEATHER SERVICE.

SEVERE THUNDERSTORMS CONTAIN WINDS GREATER THAN 58 MILES AN HOUR...
DIME SIZE HAIL OR LARGER...VERY HEAVY RAINS AND DEADLY LIGHTNING.
 
FRANKLIN/GIGI

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 11, 3:43 PM EDTSevere Thunderstorm WarningPHIBerks62 min
Jun 11, 2:38 PM EDTSevere Thunderstorm WarningPHIKent32 min
Jun 11, 6:11 PM EDTFlash Flood WarningPHINew Castle3 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1996Severe Thunderstorm Warnings in Delaware, 1996Every severe thunderstorm warning in 1996

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.