Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 1, NWS Philadelphia/Mount Holly

February 22, 19974 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Feb 22, 1997, 12:31 PM EST for 4 counties in Pennsylvania. It was in force for 64 min. 3 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
Feb 22, 1997, 12:31 PM EST (17:31 UTC)
Expired
Feb 22, 1997, 1:35 PM EST
In force
64 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

Counties Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 74 km from the middle of the area, began a volume at 17:35 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
Feb 22, 12:40 PM ESTThunderstorm Wind 52Buckingham Vly, PA
Feb 22, 12:40 PM ESTThunderstorm WindWawa, PA
Feb 22, 12:45 PM ESTThunderstorm WindCountywide, 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 225 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 1997-02-22Temperature 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°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 1997-02-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 170 square meters per square second.1939587897117136Sfc1 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
912 m above ground
0-6 km bulk shear
77 kt
0-1 km storm-relative helicity
170 m²/s²
0-3 km storm-relative helicity
194 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.

000 
TTAA00 KPHL 221734 RRA
SVRPHL
PAC017-045-091-101-221835-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
1231 PM EST SAT FEB 22 1997

THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY NJ HAS
ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 135 PM EST
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN  PENNSYLVANIA

   ...SOUTHEASTERN BUCKS COUNTY
   ...SOUTHEASTERN MONTGOMERY
   ...DELAWARE COUNTY
   ...PHILADELPHIA COUNTY
 

A LINE OF THUNDERSTORMS WITH DAMAGING WIND GUSTS EXTENDED FROM NEAR
THE WILLOW GROVE N.A.S. SOUTHWEST TO THE CHESTER COUNTY/DELAWARE
COUNTY LINE.  THIS LINE TOOK DOWN TREES IN COATESVILLE AND
COLLEGEVILLE.

IF YOU ARE IN THE PATH OF THIS STORM...SEEK SHELTER NOW.  AFTER THE
STORM HAS PASSED...REPORT ANY SEVERE WEATHER OR FLOODING TO YOUR
LOCAL LAW ENFORCEMENT AGENCY AND HAVE THEM RELAY YOUR SEVERE WEATHER
REPORT ON TO THE NATIONAL WEATHER SERVICE.

SEVERE THUNDERSTORMS CONTAIN WINDS GREATER THAN 58 MILES AN HOUR...
DIME SIZE HAIL OR LARGER...VERY HEAVY RAINS AND DEADLY LIGHTNING.

STAY TUNED TO NOAA WEATHER RADIO...THE VOICE OF THE NATIONAL WEATHER
SERVICE...OR TO COMMERCIAL RADIO OR TELEVISION STATIONS FOR THE
LATEST STORM INFORMATION.
 

&

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1997Every severe thunderstorm warning in 1997

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.