Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1990
Severe Thunderstorm Warning 12, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 9, 1990, 12:50 AM EDT for Chester County, Delaware County, Philadelphia County, Pennsylvania. It was in force for 3 hr. 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
- Jun 9, 1990, 12:50 AM EDT (04:50 UTC)
- Expired
- Jun 9, 1990, 3:45 AM EDT
- In force
- 3 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Whole counties
Counties Chester County, PA, 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 |
|---|---|---|---|
| Jun 9, 1:55 AM EDT | Thunderstorm Wind 0 | 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 00:00Z, 4.8 hours before the alert went out and 98 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
- 7 J/kg
- Mixed-layer CIN
- -317 J/kg
- Mixed-layer LCL
- 1171 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 139 m²/s²
- 0-3 km storm-relative helicity
- 193 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.5
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KPHL 090555 SVRPHL PAC029-045-101-090745- BULLETIN - EBS ACTIVATION REQUESTED SEVERE THUNDERSTORM AND URBAN AND SMALL STREAM FLOOD WARNING NATIONAL WEATHER SERVICE PHILADELPHIA PA 150 AM EDT SAT JUN 9 1990 THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A SEVERE THUNDERSTORM AND URBAN AND SMALL STREAM FLOOD WARNING EFFECTIVE UNTIL 345 AM EDT FOR PEOPLE IN THE FOLLOWING LOCATIONS... IN SOUTHEAST PENNSYLVANIA ...CHESTER COUNTY...DELAWARE COUNTY...PHILADELPHIA COUNTY AT 145 AM...WEATHER SERVICE RADAR SHOWED SEVERE THUNDERSTORMS IN CENTRAL CHESTER COUNTY. A SPOTTER FROM DOWNINGTOWN IN CHESTER COUNTY REPORTED PEA SIZE HAIL AND HEAVY RAINS. ANOTHER SPOTTER REPORTED GOLF BALL SIZE HAIL IN COATSVILLE IN CHESTER COUNTY. 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. HEAVY RAINS WITH THIS THUNDERSTORM MAY CAUSE FLOODING OF SMALL STREAMS AND UNDERPASSES VERY QUICKLY. DO NOT DRIVE YOUR CAR INTO AREAS WHERE THE WATER COVE,RS THE ROADWAY. THE WATER MAY BE DEEPER THAN YOU THINK. IF CAUGHT IN RISING WATERS...ABANDON YOUR CAR QUICKLY. MOVE TO HIGHER GROUND.
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jun 9, 1:50 AM EDT | Flash Flood Warning | PHI | Chester, Delaware, Philadelphia | 115 min |
| Jun 9, 2:33 AM EDT | Flash Flood Warning | PHI | Montgomery | 57 min |
| Jun 9, 2:33 AM EDT | Severe Thunderstorm Warning | PHI | Montgomery | 57 min |
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.