Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 14, NWS Philadelphia/Mount Holly

June 16, 1991Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 16, 1991, 3:57 PM EDT for Bucks County, Pennsylvania. It was in force for 33 min.

The area

The counties it named.

The facts

Issued
Jun 16, 1991, 3:57 PM EDT (19:57 UTC)
Expired
Jun 16, 1991, 4:30 PM EDT
In force
33 min
Issued by
NWS Philadelphia/Mount Holly
Area
Whole counties

County Bucks County, PA

The nearest sounding before it

Atlantic City In, NJ (KACY), launched 12:00Z, 8.0 hours before the alert went out and 111 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, Atlantic City In, NJ at 12:00Z on 1991-06-16Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 529 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, Atlantic City In, NJ at 12:00Z on 1991-06-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 square meters per square second.1939Sfc1 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
529 J/kg
Mixed-layer CIN
-119 J/kg
Mixed-layer LCL
1442 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
69 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 161957
SVRPHL
PAC017-162030-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE PHILADELPHIA PA
357 PM EDT SUN JUN 16 1991
 
THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL  430 PM EDT
FOR PEOPLE IN THE FOLLOWING LOCATION...
 
IN SOUTHEAST PENNSYLVANIA
 
   ...SOUTHERN BUCKS COUNTY
 
STORM SPOTTER REPORTS AT 345 PM FROM THE WARRINGTON AREA IN
SOUTHWESTERN BUCKS COUNTY INDICATED A THUNDERSTORM WITH WIND GUSTS TO
NEAR 60 MPH. THIS THUNDERSTORM IS MOVING EAST AT 20 TO 25 MPH AND WILL
PASS THROUGH SOUTHERN BUCKS COUNTY BETWEEN NOW AND 430 PM.
 
THIS IS A DANGEROUS STORM.  IF YOU ARE IN THE WARNED AREA...PREPARE
FOR STRONG DAMAGING WINDS...LARGE HAIL...VERY HEAVY RAIN AND DEADLY
LIGHTNING.  SHOULD THE STORM APPROACH YOU...SEEK IMMEDIATE SHELTER
INDOORS...BUT DO NOT STAND NEAR WINDOWS.  MOBILE HOMES ARE MOST
VULNERABLE TO HIGH WINDS AND SHOULD BE AVOIDED.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Jun 16, 11:26 AM EDT, 4 hours 31 minutes before
PAZ012-NJZ002-280600-

SPECIAL WEATHER STATEMENT - THUNDERSTORM POTENTIAL
NATIONAL WEATHER SERVICE PHILADELPHIA PA
11 25 AM EDT SUN JUN 16 1991

A COLD FRONT EXTENDS FROM A LOW PRESSURE AREA NEAR LAKE HURON
SOUTHWESTWARD TO NORTHERN ARKANSAS THEN TO THE TEXAS PANHANDLE.
AHEAD OF THIS FRONT IS A HOT...MOIST AND UNSTABLE AIRMASS.
THUNDERSTORMS WILL DEVELOP LATER THIS AFTERNOON AND BE SCATTERED
FROM NEW ENGLAND SOUTH TO THE GULF OF MEXICO.

SKIES ARE MOSTLY SUNNY OVER SOUTHEASTERN PENNSYLVANIA AND SOUTHERN
NEW JERSEY LATE THIS SUNDAY MORNING.  DURING THE AFTERNOON SCATTERED
CLOUDS WILL FORM WHICH COULD DEVELOP INTO THUNDERSTORMS ANYTIME AFTER
2PM.  STORMS COULD DEVELOP ANYWHERE OVER THE FORECAST AREA...BUT
ARE MOST LIKELY OVER NORTHEASTERN PENNSYLVANIA.

MOVEMENT OF THE STORMS WILL BE FROM NORTHWEST TO SOUTHEAST AT 15 TO
20 MPH. STORMS WITH HAIL AND/OR STRONG AND GUSTY WINDS WILL MOST
LIKELY BE OVER SOUTHERN PENNSYLVANIA AND SOUTHERN NEW JERSEY ANYTIME
AFTER 4 PM.

IF THREATENING WEATHER APPROACHES...SEEK IMMEDIATE SHELTER INDOORS...
BUT DO NOT STAND NEAR WINDOWS.  MOBILE HOMES ARE MOST VULNERABLE TO
HIGH WINDS AND SHOULD BE AVOIDED IF AT ALL POSSIBLE.  IF OUTDOORS AVOID
TREES IF LIGHTNING IS OCCURRING.

JEJ
Special weather statement, Jun 16, 2:11 PM EDT, 1 hour 46 minutes before
DEZ003-002-001-162015-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON DE
210 PM EDT SUN JUN 16 1991

...SEVERE THUNDERSTORM WATCH ISSUED FOR DELAWARE...

THE NATIONAL SEVERE STORMS FORECAST CENTER HAS ISSUED A SEVERE
THUNDERSTORM WATCH FOR DELAWARE AND ADJACENT COSTAL WATERS EFFECTIVE
THIS SUNDAY AFTERNOON UNTIL 8 PM THIS EVENING.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 80 STATUTE MILES EAST
AND WEST OF A LINE FROM 50 MILES WEST SOUTHWEST OF RICHMOND VIRGINIA
TO 40 MILES NORTH NORTHEAST OF LAKEHURST NEW JERSEY.

REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE
FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA.  PERSONS IN
THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER
CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS.

LYLES
Special weather statement, Jun 16, 2:37 PM EDT, 1 hour 20 minutes before
PAZ012-NJZ002-160000-

SPECIAL WEATHER STATEMENT - THUNDERSTORM WATCH
NATIONAL WEATHER SERVICE PHILADELPHIA PA
235 PM EDT SUN JUN 16 1991

A SEVERE THUNDERSTORM WATCH HAS BEEN ISSUED FROM 230 PM EDT UNTIL 8 PM
EDT FOR SOUTHEAST PENNSYLVANIA AND CENTRAL AND SOUTHERN NEW JERSEY.
A COLD FRONT APPROACHING WESTERN PENNSYLVANIA THROUGH CENTRAL OHIO
EARLY THIS AFTERNOON IS MOVING TO THE EAST INTO UNSTABLE AIR OVER
EASTERN PENNSYLVANIA AND NEW JERSEY.  THUNDERSTORMS...SOME SEVERE
ARE EXPECTED TO DEVELOP OVER SOUTHEAST PENNSYLVANIA AND SOUTHERN NEW
JERSEY.

AS OF 230 PM WEATHER SEARCH RADAR AND WEATHER SATELLITE SHOWS AN
INCREASE IN THUNDERSTORM DEVELOPMENT FROM THE WILKESBARRE PENNSYLVANIA
AREA SOUTHWEST ACROSS SOUTHEAST PENNSYLVANIA TO WEST OF WASHINGTON DC.
THE THUNDERSTORMS WILL CONTINUE TO INCREASE IN INTENSITY AND COVERAGE
AS THEY MOVE EAST SOUTHEAST ABOUT 25 MPH.

IF THREATENING WEATHER APPROACHES...SEEK IMMEDIATE SHELTER INDOORS...
BUT DO NOT STAND NEAR WINDOWS.  MOBILE HOMES ARE MOST VULNERABLE TO
HIGH WINDS AND SHOULD BE AVOIDED IF AT ALL POSSIBLE.  IF OUTDOORS AVOID
TREES IF LIGHTNING IS OCCURRING.

PLEASE KEEP TUNED TO YOUR LOCAL RADIO OR TELEVISION STATION OR NOAA
WEATHE:R RADIO SHOULD A WARNING BE ISSUED BY THE NATIONAL WEATHER
SERVICE.

MR
Special weather statement, Jun 16, 3:12 PM EDT, 45 minutes before
PAZ011-016- 162100 -

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE ALLENTOWN PA
310 PM EDT SUN JUN 16 1991

...THUNDERSTORMS MOVING THROUGH EAST CENTRAL PENNSYLVANIA...

AT 300 PM EDT NATIONAL WEATHER SERVICE RADAR INDICATED NUMEROUS
SHOWERS AND THUNDERSTORMS DEVELOPING AND MOVING ACROSS MUCH OF
EAST CENTRAL PENNSYLVANIA THIS AFTERNOON.

THESE STORMS STRECHED FROM WILKES-BARRE SOUTHWEST TO NEAR ALTOONA
AND WERE MOVING SOUTHEAST AT 25 MPH. A SECOND CLUSTER OF THUNDERSTORMS
WAS LOCATED BETWEEN READING AND PHILADELPHIA.

A SEVERE THUNDERSTORM WATCH IS IN EFFECT UNTIL 8 PM EDT FOR PORTIONS OF
SOUTHEASTERN PENNSYLVANIA AND MUCH OF NEW JERSEY BUT IT DOES NOT INCLUDE
EITHER THE LEHIGH VALLEY OR POCONOS REGIONS. PERSONS IN BERKS...LEHIGH AND
NORTHAMTON COUNTIES SHOULD CONTINUE TO MONITOR THE DEVELOPING WEATHER
SITUATION BECAUSE SEVERE WEATHER CAN DEVELOP IN AND CLOSE TO THE WATCH
AREA. LISTEN TO NOAA WEATHER RADIO...LOCAL TELEVISION ASND RADIO
STATIONS FOR THE LATEST STATEMENTS AND UPDATES ON THE DEVELOPING
SITUATION.

BLACKBURN

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 16, 3:47 PM EDTSevere Thunderstorm WarningPHIDelaware43 min
Jun 16, 4:16 PM EDTSevere Thunderstorm WarningPHIMontgomery, Philadelphia29 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 1991Every severe thunderstorm warning in 1991

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.