Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1989

Severe Thunderstorm Warning 9, NWS Philadelphia/Mount Holly

March 31, 1989Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Mar 31, 1989, 4:15 PM EST for Montgomery County, Pennsylvania. It was in force for 30 min.

The area

The counties it named.

The facts

Issued
Mar 31, 1989, 4:15 PM EST (21:15 UTC)
Expired
Mar 31, 1989, 4:45 PM EST
In force
30 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Montgomery County, PA

The radar

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

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 9.3 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 12:00Z on 1989-03-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 1989-03-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 93 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
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 312116
SVRPHL
PAC091-312145-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
415 PM EST FRI MAR 31 1989
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  445 PM EST
FOR PEOPLE IN THE FOLLOWING COUNTY...
 
IN SOUTHEAST PENNSYLVANIA
          ...CENTRAL MONTGOMERY
 
AT 410 PM EST NATIONAL WEATHER SERVICE RADAR INDICATED THAT A SEVERE
THUNDERSTORM WAS LOCATED IN CENTRAL MONTGOMERY COUNTY. THIS STORM
PRODUCED HAIL AS LARGE AS PINGPONG BALL SIZE IN CHESTER COUNTY. THE
STORM WAS MOVING NORTHEAST AT 45 MILES AN HOUR.
 
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN THE WARNED AREA...XBE
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.
 
DPG

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 31, 3:30 PM ESTSevere Thunderstorm WarningPHIChester, Delaware60 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1989Every 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; the sounding from the Mesonet's radiosonde archive.