Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1987

Severe Thunderstorm Warning 21, NWS Philadelphia/Mount Holly

July 26, 1987Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 26, 1987, 11:33 AM EDT for Bucks County, Pennsylvania. It was in force for 42 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jul 26, 1987, 11:33 AM EDT (15:33 UTC)
Expired
Jul 26, 1987, 12:15 PM EDT
In force
42 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Bucks County, PA

The radar

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

What was reported inside it

TimeReportWhereRemark
Jul 26, 11:35 AM EDTHail 0.75Bucks, PA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 3.6 hours before the alert went out and 111 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 1987-07-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2642 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 1987-07-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 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
2642 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
1042 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.7

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KPHL 261540 COR
SVRPHL
PAC017-261615-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE PHILADELPHIA PA
1133 AM EDT SUN JUL 26 1987

THE NATIONAL WEATHER SERVICE HAS ISSUED A SEVERE THUNDERSTORM
WARNING EFFECTIVE UNTIL 1215 PM EDT FOR PEOPLE IN THE FOLLOWING
COUNTY OF

SOUTHEAST PENNSYLVANIA...NORTHERN BUCKS

AT 1130 AM EDT RADAR INDICATED A SEVERE THUNDERSTORM JUST EAST OF
ALLENTOWN PENNSYLVANIA MOVING TOWARD THE SOUTHEAST AT 30 MILES
AN HOUR.

 THIS IS A DANGEROUS STORM AND PEOPLE IN THE WARNED AREA SHOULD BE
PREPARED FOR STRONG DAMAGING WINDS...LARGE HAIL...VERY HEAVY RAIN
AND LIGHTNING. SHOULD THE STORM APPROACH YOU...SEEK IMMEDIATE
SHELTER. MOBILE HOMES ARE MOST VULNERABLE TO HIGH WINDS AND
SHOULD BE AVOIDED.

 A SEVERE THUNDERSTORM WATCH CONTINUES FOR PORTIONS OF
 SOUTHEASTERN PENNSYLVANIA AND PORTIONS OF SOUTHERN NEW JERSEY
 UNTIL 400 PM EDT.

 NPC

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1987Every severe thunderstorm warning in 1987

Sources

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