Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1993

Severe Thunderstorm Warning 8, NWS Philadelphia/Mount Holly

June 9, 1993Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 9, 1993, 4:13 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 47 min.

The area

The counties it named.

The facts

Issued
Jun 9, 1993, 4:13 PM EDT (20:13 UTC)
Expired
Jun 9, 1993, 5:00 PM EDT
In force
47 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Chester County, PA, Montgomery County, PA

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 8.2 hours before the alert went out and 115 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 12:00Z on 1993-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 366 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 12:00Z on 1993-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 116 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
366 J/kg
Mixed-layer CIN
-215 J/kg
Mixed-layer LCL
971 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
116 m²/s²
0-3 km storm-relative helicity
136 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 092015 RRA
SVRPHL
PAC029-091-092100-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
413 PM EDT WED JUN 9 1993
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  500 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...EASTERN CHESTER COUNTY...SOUTHERN MONTGOMERY COUNTY
 
AT 410 PM EDT RADAR SHOWED DEVELOPING THUNDERSTORMS IN WESTERN
CHESTER COUNTY. OTHER THUNDERSTORMS IN THIS VICINITY HAVE PRODUCED
DAMAGING WINDS AND VERY HEAVY RAINS IN A SHORT PERIOD OF TIME.
THE THUNDERSTORMS WERE MOVING EAST AT 45 MPH.
 
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR PARTS OF
SOUTHERN PENNSYLVANIA UNTIL 8 PM EDT.
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN THE WARNED AREA...PREPARE
FOR STRONG DAMAGING WINDS...LARGE HAIL...VERY HEAVY RAIN AND DEADLY
LIGHTNING.  SHOULD THE STORM APPROACH YOU...SEEK IMMEDIATE SHEbLTER
INDOORS...BUT DO NOT STAND NEAR WINDOWS.  MOBILE HOMES ARE MOST
VULNERABLE TO HIGH WINDS AND SHOULD BE AVOIDED.
 
EBERWINE/CLAVIN

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 3:16 PM EDTSevere Thunderstorm WarningPHIBucks44 min
Jun 9, 4:30 PM EDTSevere Thunderstorm WarningPHIDelaware, Philadelphia45 min
Jun 9, 7:43 PM EDTSevere Thunderstorm WarningPHIMontgomery, Philadelphia62 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1993Every severe thunderstorm warning in 1993

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.