Alert archive / Maryland / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 47, NWS Philadelphia/Mount Holly

June 1, 1998Cecil County, Maryland; Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 1, 1998, 12:40 AM EDT for Cecil County, Maryland; Chester County, Pennsylvania. It was in force for 50 min. 5 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
Jun 1, 1998, 12:40 AM EDT (04:40 UTC)
Expired
Jun 1, 1998, 1:30 AM EDT
In force
50 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Cecil County, MD, Chester County, PA

The radar

The Dover AFB radar (KDOX), 110 km from the middle of the area, began a volume at 04:39 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

TimeReportWhereRemark
Jun 1, 12:40 AM EDTThunderstorm Wind 62Atglen, PA
Jun 1, 12:43 AM EDTTornado F1Daleville, PA
Jun 1, 12:45 AM EDTThunderstorm Wind 50Calvert, MD
Jun 1, 12:45 AM EDTThunderstorm Wind 50Bucktown, PA
Jun 1, 12:52 AM EDTTornado F1Lenape, 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.

IssuedProductOfficeLasted
May 31, 10:00 PM EDTTornado WatchSPC6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 4.7 hours before the alert went out and 161 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, Washington/Dulle, VA at 00:00Z on 1998-06-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3110 joules per kilogram.LCLLFCEL10008507005003002001001 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, Washington/Dulle, VA at 00:00Z on 1998-06-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 203 square meters per square second.193958Sfc1 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
3110 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
1063 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
203 m²/s²
0-3 km storm-relative helicity
277 m²/s²
Significant tornado parameter
3.0
Supercell composite
18.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

102 
WUUS1 KPHL 010441 RRA
SVRPHL
MDC015-PAC029-010530-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1240 AM EDT MON JUN 1 1998

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CHESTER COUNTY IN PENNSYLVANIA
  CECIL COUNTY IN MARYLAND

* UNTIL 130 AM EDT

* AT 1247 AM EDT... NATIONAL WEATHER SERVICE DOPPLER RADAR
  INDICATED A LINE OF SEVERE THUNDERSTORMS IN EASTERN LANCASTER AND
  HARFORD COUNTIES...MOVING SOUTHEAST AT 45 MPH.

A TORNADO WATCH REMAINS IN EFFECT FOR THE AREA. SEVERE
THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH
LITTLE OR NO ADVANCE WARNING.

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.

KRAUS/WANTON

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 1, 1:00 AM EDTSevere Thunderstorm WarningPHIKent50 min
Jun 1, 1:21 AM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's49 min
May 31, 8:11 PM EDTSevere Thunderstorm WarningPHIBerks64 min
May 31, 8:37 PM EDTTornado WarningPHIBerks33 min
May 31, 9:07 PM EDTTornado WarningPHIBerks, Lehigh48 min
May 31, 9:14 PM EDTSevere Thunderstorm WarningPHIBerks46 min
May 31, 9:39 PM EDTTornado WarningPHIBerks, Chester36 min
May 31, 9:43 PM EDTTornado WarningPHIBucks32 min
May 31, 10:01 PM EDTTornado WarningPHIMonroe34 min
May 31, 10:21 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery49 min
May 31, 11:01 PM EDTSevere Thunderstorm WarningPHINorthampton34 min
Jun 1, 12:17 AM EDTSevere Thunderstorm WarningPHIBerks48 min
Jun 1, 12:54 AM EDTSevere Thunderstorm WarningPHIBucks31 min
Jun 1, 1:00 AM EDTSevere Thunderstorm WarningPHIDelaware50 min
Jun 1, 1:15 AM EDTSevere Thunderstorm WarningPHIPhiladelphia35 min

Nearby

Severe Thunderstorm Warnings in Maryland, 1998Severe 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.