Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1989

Severe Thunderstorm Warning 22, NWS Philadelphia/Mount Holly

June 9, 1989Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 9, 1989, 8:17 PM EDT for Delaware County, Pennsylvania. It was in force for 58 min.

The area

The counties it named.

The facts

Issued
Jun 9, 1989, 8:17 PM EDT (00:17 UTC)
Expired
Jun 9, 1989, 9:15 PM EDT
In force
58 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Delaware County, PA

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 00:00Z, 0.3 hours before the alert went out and 93 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, Atlantic City In, NJ at 00:00Z on 1989-06-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 562 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Atlantic City In, NJ at 00:00Z on 1989-06-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 square meters per square second.19395878Sfc1 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
562 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
594 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
122 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 100021 RRA
SVRPHL
NJC005-007-PAC045-101-100115-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
817 PM EDT FRI JUN 9 1989
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  915 PM EDT
FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN SOUTH NEW JERSEY
          ...WESTERN BURLINGTON...NORTHERN CAMDEN
IN SOUTHEAST PENNSYLVANIA
          ...DELAWARE...PHILADELPHIA
 
WEATHER SERVICE RADAR AT 815 PM EDT INDICATED SEVERE THUNDERSTORMS
OVER DELAWARE AND PHILADELPHIA COUNTIES OF SOUTHEASTERN
PENNSYLVANIA...AND OVER WESTERN BURLINGTON AND NORTHERN CAMDEN
COUNTIES OF SOUTHERN NEW JERSEY. THESE THUNDERSTORMS WERE MOVING
NORTHEAST AT 20 MILES AN HOUR...AND WILL MOVE THROUGH THE WARNED
COUNTIES BY 915 PM THIS EVENING.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DAMAGING WINDS...LARGE
HAIL...VERY HEAVY RAIN...AND DEADLY LIGHTNING ARE ALL POSSIBLE IN
SEVERE THUNDERSTORMS.  THESE THUNDERSTORMS ALSO HAVE THE POTENTIAL TO
PRODUCE TORNADOES.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER
CROSSINGS.  HEAVY RAINS FLOOD ROADS QUZICKLY.
 
WERT

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 8:17 PM EDTSevere Thunderstorm WarningPHIPhiladelphia58 min
Jun 9, 11:09 PM EDTFlash Flood WarningPHIDelaware3 hr
Jun 9, 11:36 PM EDTFlash Flood WarningPHIBucks3 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1989Every severe thunderstorm warning in 1989

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive.