Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1989

Severe Thunderstorm Warning 8, NWS Philadelphia/Mount Holly

March 31, 1989Chester County, Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Mar 31, 1989, 3:30 PM EST for Chester County, Delaware County, Pennsylvania. It was in force for 60 min. 3 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: Mar 31, 1989, 3:30 PM EST (20:30 UTC)
Expired: Mar 31, 1989, 4:30 PM EST
In force: 60 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

Counties Chester County, PA, Delaware 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

Time	Report	Where
Mar 31, 3:32 PM EST	Hail 1.75	Chester, PA
Mar 31, 3:48 PM EST	Hail 1.75	Chester, PA
Mar 31, 3:56 PM EST	Hail 0.75	Chester, 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, 8.5 hours before the alert went out and 107 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 143 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 312031
SVRPHL
PAC029-045-312130-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
330 PM EST FRI MAR 31 1989
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  430 PM EST
FOR PEOPLE IN THE FOLLOWING COUNTIES...
 
IN SOUTHEAST PENNSYLVANIA
          ...EASTERN CHESTER...DELAWARE
 
AT 325 PM EST NATIONAL WEATHER SERVICE RADAR INDICATED A SEVERE
THUNDERSTORM ON THE PENNSYLVANIA MARYLAND BORDER IN SOUTHERN CHESTER
COUNTY. ALSO AT 325 PM EST PINGPONG BALL SIZE HAIL WAS REPORTED JUST
SOUTH OF AVONDALE IN CHESTER COUNTY.
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN THE WARNED AREA...BE
PREPARED FOR STRONG DAMAGING WINDS...LARGE HAIL...VERY HEAVY RAIN
AND DANGEROUS LIGHTNING.  SHOULD THE STORM APPROACH YOU...SEEK
IMMEDIATE SHELTER.  MOBILE HOMES ARE MOST VULNERABLE TO HIGH WINDS
AND SHOULD BE AVOIDED.
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DO NOT STAND BY WINDOWS.  DAMAGING WINDS...LARGE
HAIL...VERY HEAVY RAIN...AND DEADLY LIGHTNING ARE ALL POSSIBLE IN
SEVERE THUNDERSTORMS.  MOTORISTS SHOULD NOT DRIVE INTO LOW WATER
CROSSINGS.  HEAVY RAINS FLOOD ROADS QUICKLY.
 
DPG

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 31, 4:15 PM EST	Severe Thunderstorm Warning	PHI	Montgomery	30 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1989 Every severe thunderstorm warning in 1989

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.