Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1989
Severe Thunderstorm Warning 52, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Nov 20, 1989, 8:55 PM EST for Delaware County, Philadelphia County, Pennsylvania. It was in force for 65 min. 7 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
- Nov 20, 1989, 8:55 PM EST (01:55 UTC)
- Expired
- Nov 20, 1989, 10:00 PM EST
- In force
- 65 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Whole counties
Counties Delaware County, PA, Philadelphia 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 | Remark |
|---|---|---|---|
| Nov 20, 9:07 PM EST | Thunderstorm Wind 69 | Delaware, PA | |
| Nov 20, 9:17 PM EST | Thunderstorm Wind 61 | Philadelphia, PA | |
| Nov 20, 9:25 PM EST | Thunderstorm Wind 53 | Philadelphia, PA | |
| Nov 20, 9:25 PM EST | Thunderstorm Wind 52 | Delaware, PA | |
| Nov 20, 9:25 PM EST | Thunderstorm Wind 53 | Delaware, PA | |
| Nov 20, 9:25 PM EST | Thunderstorm Wind 0 | Philadelphia, PA | |
| Nov 20, 9:41 PM EST | Thunderstorm Wind 0 | Philadelphia, 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 00:00Z, 1.9 hours before the alert went out and 87 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1712 m above ground
- 0-6 km bulk shear
- 53 kt
- 0-1 km storm-relative helicity
- 102 m²/s²
- 0-3 km storm-relative helicity
- 197 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000
TTAA00 KPHL 210158 RRA
SVRPHL
NJC021-PAC045-101-210300-
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
855 PM EST MON NOV 20 1989
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1000 PM EST
FOR PEOPLE IN THE FOLLOWING COUNTIES...
IN WEST CENTRAL NEW JERSEY
...MERCER
IN SOUTHEAST PENNSYLVANIA
...DELAWARE...PHILADELPHIA
THUNDERSTORMS WITH WIND GUSTS UP TO 75 MPH WERE REPORTED WITH A LINE
OF THUNDERSTORMS AS THEY MOVED THROUGH THE LEHIGH AND LOWER
SUSQUEHANNA VALLEYS. IN POTTSTOWN PENNSYLVANIA...A NATIONAL WEATHER
SERVICE SPOTTER REPORTED WINDS OF 60 TO 65 MPH. THE THUNDERSTORMS WERE
MOVING SOUTHEAST AT 50 MPH AND WILL MOVE INTO THE WARNED COUNTIES BY
905 PM.
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.
A SEVERE THUNDERSTORM WATCH CONTINUES FOR SOUTHEASTERN
PENNSYLVANIA AND SOUTHERN NEW JERSEY UNTIL 2 AM EDT. REMEMBER
SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH
LITTLE OR NO ADVANCED WARNING.The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 20, 8:44 PM EST | Severe Thunderstorm Warning | PHI | Bucks, Montgomery | 61 min |
| Nov 20, 8:44 PM EST | Severe Thunderstorm Warning | PHI | Chester | 61 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.