Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1998
Severe Thunderstorm Warning 157, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 7, 1998, 1:04 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 61 min. 2 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
- Sep 7, 1998, 1:04 PM EDT (17:04 UTC)
- Expired
- Sep 7, 1998, 2:05 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 Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 17:06 UTC, the scan nearest the moment this went out.
Open the radar archive at this moment
The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 7, 1:15 PM EDT | Thunderstorm Wind 57 | Bucktown, PA | |
| Sep 7, 1:35 PM EDT | Thunderstorm Wind 50 | West 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.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Sep 7, 10:45 AM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 5.1 hours before the alert went out and 203 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
- 114 J/kg
- Mixed-layer CIN
- -252 J/kg
- Mixed-layer LCL
- 2079 m above ground
- 0-6 km bulk shear
- 24 kt
- 0-1 km storm-relative helicity
- 90 m²/s²
- 0-3 km storm-relative helicity
- 96 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
359 WUUS1 KPHL 071705 RRA SVRPHL PAC029-091-071805- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 104 PM EDT MON SEP 7 1998 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... CHESTER COUNTY IN PENNSYLVANIA MONTGOMERY COUNTY IN PENNSYLVANIA * UNTIL 205 PM EDT * AT 100 PM EDT... A SEVERE THUNDERSTORM WAS INDICATED 9 MILES NORTH NORTHWEST OF ELVERSON... BY NATIONAL WEATHER SERVICE DOPPLER RADAR... MOVING EAST 45 MPH. * THE SEVERE THUNDERSTORM IS EXPECTED TO AFFECT MOST OF THE WARNED COUNTIES INCLUDING THE AREAS AROUND COATESVILLE...DOWNINGTOWN... POTTSTOWN AND NORRISTOWN. THESE STORMS DOWNED TREES AND DAMAGED ROOFS IN THE READING AREA OF BERKS COUNTY. WINDS GUSTED TO 70 MPH AT READING AIRPORT. THIS IS A DANGEROUS STORM. MOVE INSIDE A STRONG BUILDING AND DO NOT STAND NEAR WINDOWS. FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER RADIO...YOUR LOCAL RADIO OR TELEVISION STATIONS...OR YOUR CABLE TELEVISION OUTLET. NC/AMC &
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 7, 12:22 PM EDT | Severe Thunderstorm Warning | PHI | Carbon | 53 min |
| Sep 7, 12:30 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 60 min |
| Sep 7, 12:35 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 60 min |
| Sep 7, 12:46 PM EDT | Severe Thunderstorm Warning | PHI | Lehigh, Northampton | 59 min |
| Sep 7, 1:19 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 61 min |
| Sep 7, 1:39 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 51 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 1998Every severe thunderstorm warning in 1998
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; radar from the NEXRAD Level II archive.