Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 57, NWS Philadelphia/Mount Holly

July 2, 1994Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 2, 1994, 4:28 PM EDT for Chester County, Pennsylvania. It was in force for 32 min.

The area

The counties it named.

The facts

Issued
Jul 2, 1994, 4:28 PM EDT (20:28 UTC)
Expired
Jul 2, 1994, 5:00 PM EDT
In force
32 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Chester County, PA

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 8.5 hours before the alert went out and 122 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 1994-07-02Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 634 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 1994-07-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 14 square meters per square second.1939Sfc1 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
634 J/kg
Mixed-layer CIN
-18 J/kg
Mixed-layer LCL
922 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
14 m²/s²
0-3 km storm-relative helicity
35 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 
WUUS1 KPHL 022030 RRA
SVRPHL
PAC029-022100-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
428 PM EDT SAT JUL 2 1994
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  500 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...EASTERN CHESTER COUNTY
 
NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A DEVELOPING SEVERE
THUNDERSTORM IN CENTRAL CHESTER COUNTY NORTHWEST OF DOWINGTOWN. MOVEMENT
WAS EAST AT ABOUT 20 MILES AN HOUR.
 
HEAVY RAINS WITH THIS THUNDERSTORM MAY CAUSE FLOODING OF SMALL
STREAMS AND UNDERPASSES VERY QUICKLY.  DO NOT DRIVE YOUR CAR INTO
AREAS WHERE THE WATER COVERS THE ROADWAY.  THE WATER MAY BE DEEPER
THAN YOU THINK.  IF CAUGHT IN RISING WATERS...ABANDON YOUR CAR
QUICKLY.  MOVE TO HIGHER GROUND.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 2, 4:58 PM EDTSevere Thunderstorm WarningPHIChester47 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1994Every severe thunderstorm warning in 1994

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.