Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 2, NWS Philadelphia/Mount Holly

February 18, 1998Philadelphia County, Pennsylvania; Camden County, New Jersey

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Feb 18, 1998, 10:31 AM EST for Philadelphia County, Pennsylvania; Camden County, New Jersey. It was in force for 34 min. 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: Feb 18, 1998, 10:31 AM EST (15:31 UTC)
Expired: Feb 18, 1998, 11:05 AM EST
In force: 34 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

Counties Camden County, NJ, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 54 km from the middle of the area, began a volume at 15:30 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
Feb 18, 10:44 AM EST	Hail 0.88	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.

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 3.5 hours before the alert went out and 102 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1164 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 75 m²/s²
0-3 km storm-relative helicity: 103 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.

404 
WUUS1 KPHL 181537 RRA
SVRPHL
PAC101-NJC007-181605-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1031 AM EST WED FEB 18 1998

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1105 AM EST FOR PEOPLE
IN THE FOLLOWING LOCATION...

IN PENNSYLVANIA

   ...PHILADELPHIA COUNTY

IN NEW JERSEY
   ...WESTERN CAMDEN COUTY

AT 1029 AM EST... SPOTTERS REPORTED A SEVERE THUNDERSTORM WITH PING-
PONG SIZE HAIL AT THE WALT WHITMAN BRIDGE.


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.

DO NOT DRIVE YOUR CAR WHERE WATER COVERS THE ROADWAY. THE WATER
MAY BE DEEPER THAN YOU THINK. IF CAUGHT IN RISING FLOOD WATERS...
ABANDON YOUR CAR QUICKLY AND MOVE TO HIGHER GROUND.

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

WN


&

The office that day

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

Issued	Product	Office	Counties	Lasted
Feb 18, 10:56 AM EST	Severe Thunderstorm Warning	PHI	Bucks	34 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1998 Severe Thunderstorm Warnings in New Jersey, 1998 Every 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.