Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1997

Severe Thunderstorm Warning 11, NWS Philadelphia/Mount Holly

May 1, 1997Bucks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 1, 1997, 5:32 PM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 28 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: May 1, 1997, 5:32 PM EDT (21:32 UTC)
Expired: May 1, 1997, 6:00 PM EDT
In force: 28 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

Counties Bucks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 79 km from the middle of the area, began a volume at 21:34 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
May 1, 5:35 PM EDT	Hail 1	Quakertown, PA
May 1, 5:50 PM EDT	Thunderstorm Wind	Northern, 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
May 1, 4:00 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 9.5 hours before the alert went out and 116 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: 833 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 164 m²/s²
0-3 km storm-relative helicity: 178 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 012132 RRA
SVRPHL
PAC017-091-012200-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA/MOUNT HOLLY NJ
532 PM EDT THU MAY 1 1997

THE NATIONAL WEATHER SERVICE IN PHILADELPHIA/MOUNT HOLLY NJ HAS
ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 600 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN  PENNSYLVANIA

   ...NORTHERN MONTGOMERY COUNTY
   ...NORTHERN BUCKS COUNTY
 
AT 530 PM EDT...A SEVERE THUNDERSTORM WAS INDICATED BY NWS DOPPLER
RADAR 4 MILES WEST NORTHWEST OF POTTSTOWN MOVING EAST NORTHEAST AT 40
MPH.

THIS STORM MAY AFFECT THE FOLLOWING NEARBY AREAS... POTTSTOWN...
GILBERTSVILLE... CONGO... FREDERICK... OBELISK... LIMERICK...
SCHWENKSVILLE... GREEN LANE... PENNSBURG... GRATERFORD... PALM... EAST
GREENVILLE... RED HILL... HARLEYSVILLE... TRUMBAUERSVILLE AND
TELFORD.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT FOR THE AREA.

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.
 
JONES/MIKETTA/SZATKOWSKI

The office that day

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

Issued	Product	Office	Counties	Lasted
May 1, 4:38 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	52 min
May 1, 4:38 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	52 min
May 1, 6:09 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	46 min
May 1, 6:18 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	32 min
May 1, 6:30 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	40 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1997 Every 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.