Alert archive / Maryland / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 21, NWS Philadelphia/Mount Holly

April 17, 1998Cecil County, Maryland; Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 17, 1998, 5:02 PM EDT for Cecil County, Maryland; Chester County, Pennsylvania. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 17, 1998, 5:02 PM EDT (21:02 UTC)
Expired
Apr 17, 1998, 5:50 PM EDT
In force
48 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Cecil County, MD, Chester County, PA

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Apr 17, 3:00 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.0 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 12:00Z on 1998-04-17Temperature 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, Washington/Dulle, VA at 12:00Z on 1998-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -67 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
1936 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
-67 m²/s²
0-3 km storm-relative helicity
-46 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.

928 
WUUS1 KPHL 172104 RRA
SVRPHL
MDC015-PAC029-172150-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
502 PM EDT FRI APR 17 1998

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 550 PM EDT

* AT 500 PM EDT... RADAR AND SPOTTER REPORTS SHOWED A SEVERE
  THUNDERSTORM 5 MILES NORTHWEST OF PILOT MOVING EAST AT 25 MPH.

* THIS STORM MAY AFFECT THE FOLLOWING NEARBY AREAS...  PILOT...
  ROWLANDSVILLE...  WEST NOTTINGHAM...  RISING SUN...  WOODLAWN...
  NOTTINGHAM...  OXFORD...  CALVERT...  BAY VIEW...  KEMBLESVILLE
  AND  NORTH EAST.

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. SEVERE
THUNDERSTORMS CAN AND DO PRODUCE TORNADOES...A TORNADO WAS SPOTTED
IN LANCASTER COUNTY PENNSYLVANIA NEAR WAKEFIELD SHORTLY AFTER 445
PM NEAR HIGHWAY 222 BY AN OFF DUTY POLICE OFFICER.


FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER
RADIO...YOUR LOCAL RADIO OR TELEVISION STATIONS...OR YOUR CABLE
TELEVISION OUTLET.

JE/


&

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 17, 6:46 PM EDTSevere Thunderstorm WarningPHIQueen Anne's34 min
Apr 17, 3:49 PM EDTSevere Thunderstorm WarningPHIBerks36 min
Apr 17, 3:53 PM EDTSevere Thunderstorm WarningPHIMonroe47 min
Apr 17, 4:26 PM EDTSevere Thunderstorm WarningPHIBerks34 min
Apr 17, 4:54 PM EDTSevere Thunderstorm WarningPHIBucks36 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; the sounding from the Mesonet's radiosonde archive.