Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 12, NWS Philadelphia/Mount Holly

May 25, 1994Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 25, 1994, 4:30 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 60 min.

The area

The counties it named.

The facts

Issued
May 25, 1994, 4:30 PM EDT (20:30 UTC)
Expired
May 25, 1994, 5:30 PM EDT
In force
60 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, 8.5 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 1994-05-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 255 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 1994-05-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 144 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
255 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
1328 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
144 m²/s²
0-3 km storm-relative helicity
181 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 
TTAA00 KPHL 252030
SVRPHL
PAC029-091-252130-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
430 PM EDT WED MAY 25 1994
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  530 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...NORTHERN CHESTER COUNTY...WESTERN MONTGOMERY COUNTY
 
AT 430 PM...NATIONAL WEATHER SERVICE RADAR SHOWED A SEVERE THUNDERSTORM
OVER NORTHEASTERN LANCASTER COUNTY. IT WAS MOVING TOWARD THE EAST AT
ABOUT 30 MPH...AND WILL MOVE THROUGH NORTHERN CHESTER AND WESTERN
MONTGOMERY COUNTISE BY 530 PM.
 
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 SHELTER
INDOORS...BUT DO NOT STAND NEAR WINDOWS.  MOBILE HOMES ARE MOST
VULNERABLE TO HIGH WINDS AND SHOULD BE AVOIDED.
 
A TORNADO/SEVERE THUNDERSTORM WATCH CONTINUES FOR SOUTHEASTERN
PENNSYLVANIA AND SOUTHERN NEW JERSEY UNTIL 10 PM EDT.  REMEMBER
SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH
LITTLE OR NO ADVANCED WARNING.

The office that day

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

IssuedProductOfficeCountiesLasted
May 25, 5:28 PM EDTSevere Thunderstorm WarningPHIChester, Montgomery47 min
May 25, 5:30 PM EDTSevere Thunderstorm WarningPHIBucks60 min
May 25, 5:42 PM EDTSevere Thunderstorm WarningPHIDelaware48 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.