Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1994

Severe Thunderstorm Warning 87, NWS Philadelphia/Mount Holly

July 27, 1994Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 27, 1994, 11:31 PM EDT for Montgomery County, Pennsylvania. It was in force for 44 min.

The area

The counties it named.

The facts

Issued
Jul 27, 1994, 11:31 PM EDT (03:31 UTC)
Expired
Jul 28, 1994, 12:15 AM EDT
In force
44 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Montgomery County, PA

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 00:00Z, 3.5 hours before the alert went out and 112 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 1994-07-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 181 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 1994-07-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 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
181 J/kg
Mixed-layer CIN
-23 J/kg
Mixed-layer LCL
726 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
123 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 280333 RRA
SVRPHL
PAC091-280415-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
1131 PM EDT WED JUL 27 1994
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1215 AM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...MONTGOMERY COUNTY
 
AT 1125 PM...NATIONAL WEATHER SERVICE RADAR SHOWED A SEVERE
THUNDERSTORM IN NORTHERN CHESTER COUNTY.
THE STORM IS MOVING NORTHEAST AT ABOUT 30 MPH AND WILL
CROSS INTO MONTGOMERY COUNTY.
 
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.
 
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.n
 
KRAUS

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 27, 10:28 PM EDTFlash Flood WarningPHIChester62 min
Jul 27, 10:28 PM EDTSevere Thunderstorm WarningPHIChester62 min
Jul 27, 11:08 PM EDTTornado WarningPHIChester52 min
Jul 28, 12:00 AM EDTTornado WarningPHIMontgomery45 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.