Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 39, NWS Philadelphia/Mount Holly

August 13, 1990Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 13, 1990, 7:29 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 61 min. 4 reports 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
Aug 13, 1990, 7:29 PM EDT (23:29 UTC)
Expired
Aug 13, 1990, 8:30 PM EDT
In force
61 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Chester County, PA, Montgomery 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
Aug 13, 7:45 PM EDTThunderstorm Wind 56Chester, PA
Aug 13, 8:15 PM EDTThunderstorm Wind 0Montgomery, PA
Aug 13, 8:20 PM EDTThunderstorm Wind 52Montgomery, PA
Aug 13, 8:30 PM EDTThunderstorm Wind 0Montgomery, 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, 11.5 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 1990-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 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 1990-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1333 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
34 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 132331
SVRPHL
PAC029-091-140030-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
729 PM EDT MON AUG 13 1990
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  830 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATIONS...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...CHESTER COUNTY...MONTGOMERY COUNTY
 
 
A LINE OF SEVERE THUNDERSTORM WAS OCCURING ALONG THE BORDER
OF LANCASTER AND CHESTER COUNTY AT 730 PM. THIS LINE OF STORMS
WAS MOVING EAST AT 30 MPH AND WILL PUSH ACROSS CHESTER AND
MONTGOMERY COUNTIES BY 830 PM.
 
 
 
 
A SEVERE THUNDERSTORM WATCH CONTINUES FOR SOUTHEASTERN
PENNSYLVANIA UNTIL  10 PM EDT.  REMEMBER
SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH
LITTLE OR NO ADVANCED WARNING.

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1990Every severe thunderstorm warning in 1990

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.