Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 23, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 7, 1991, 11:10 AM EDT for Bucks County, Montgomery County, Pennsylvania. It was in force for 65 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
- Jul 7, 1991, 11:10 AM EDT (15:10 UTC)
- Expired
- Jul 7, 1991, 12:15 PM EDT
- In force
- 65 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Whole counties
Counties Bucks County, PA, Montgomery County, PA
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Jul 7, 11:10 AM EDT | Hail 0.75 | Montgomery, PA | |
| Jul 7, 12:00 PM EDT | Thunderstorm Wind 0 | Montgomery, 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. Storm Data before 1996 records only tornadoes, thunderstorm wind and hail.
The nearest sounding before it
Atlantic City In, NJ (KACY), launched 12:00Z, 3.2 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.
- Mixed-layer CAPE
- 1207 J/kg
- Mixed-layer CIN
- -109 J/kg
- Mixed-layer LCL
- 1172 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 76 m²/s²
- 0-3 km storm-relative helicity
- 67 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 TTAA00 KPHL 071510 SVRPHL PAC017-029-091-071615- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE PHILADELPHIA PA 1110 AM EDT SUN JUL 7 1991 THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 1215 PM EDT FOR PEOPLE IN THE FOLLOWING LOCATIONS... IN SOUTHEAST PENNSYLVANIA ...BUCKS COUNTY...CHESTER COUNTY...MONTGOMERY COUNTY NATIONAL WEATHER SERVICE RADAR INDICATED A LINE OF HEAVY THUNDERSTORMS FROM ALLENTOWN TO EAST OF READING TO EAST AND SOUTHEAST OF LANCASTER PENNSYLVANIA...SOME OF THESE MAY BE SEVERE WITH DAMAGING WINDS...LARGE HAIL AND DEADLY LIGHTNING. THESE STORM WERE MOVING TOWARD THE EAST AT AROUND 35 MILES AN HOUR. THESE ARE DANGEROUS STORMS. 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 VSTAND 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, Jul 7, 10:52 AM EDT, 18 minutes before
NJZ002>004-006-071545 SPECIAL WEATHER STATEMENT AND RADAR SUMMARY NATIONAL WEATHER SERVICE ATLANTIC CITY NJ 1040 AM EDT SUN JUL 7 1991 ...SEVERE THUNDERSTORM WATCH IN EFFECT SOUTHERN NEW JERSEY AND THE ADJACENT COASTAL WATERS UNTIL 5 PM EDT... AT 1034 AM...OUR WEATHER SEARCH RADAR SHOWED A THIN LINE OF THUNDERSTORMS WITH VERY HEAVY RAINS...STRONG GUSTY WINDS...FREQUENT DANGEROUS LIGHTNING AND POSSIBLE HAIL IN EASTERN PENNSYLVANIA KUNKLETOWN TO NORTHWEST OF READING. OTHER THUNDERSTORMS OF THIS MAGNITUDE WERE DEVELOPING IN THE LOWER SUSQUEHANNA VALLEY OF PENNSYLVANIA INTO CENTRAL NORTHERN MARYLAND...BETWEEN HARRISBURG AND LANCASTER...ALONG THE LOWER SUSQUEHANNA RIVER TO JUST NORTH OF BALTIMORE. MOVEMENT WAS EAST AT 30 MILES AN HOUR. ELSEWHERE...SCATTERED SHOWERS AND THUNERSTORMS...SOME WITH HEAVY RAIN WERE SCATTERED FROM SOUTHEAST NEW YORK STATE INTO NORTHEAST PENNSYLVANIA THEN ACROSS THE MIDDLE AND LOWER SUSQUEHANNA VALLEY OF PENNSEYLVANIA INTO CENTRAL NORTHERN MARYLAND. MOVEMENT WAS EAST AT 30 TO 35 MILES AN HOUR.
Special weather statement, Jul 7, 10:59 AM EDT, 11 minutes before
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
Special weather statement, Jul 7, 11:03 AM EDT, 7 minutes before
PAZ012-NJZ002-072100- SPECIAL WEATHER STATEMENT - SEVERE THUNDERSTORM WATCH NATIONAL WEATHER SERVICE PHILADELPHIA PA 1100 AM EDT SUN JUL 7 1991 ...SEVERE THUNDERSTORM WATCH IN EFFECT UNTIL 5 PM EDT TODAY FOR MOST OF CENTRAL AND SOUTHERN PENNSYLVANIA AND ALL OF SOUTHERN NEW JERSEY INCLUDING ADJACENT COASTAL WATERS... AT 11 AM NATIONAL WEATHER SERVICE RADAR SHOWS A LINE HEAVY THUNDERSTORMS FROM ALLENTOWN TO READING AND THROUGH LANCASTER PENNSYLVANIA. THESE WERE MOVING TOWARD THE EAST AT AROUND 35 MILES AN HOUR. OVER THE NEXT COUPLE HOURS THEY WILL MOVE THROUGH BUCKS... MONTGOMERY...CHESTER...DELAWARE AND PHILADELPHIA COUNTIES THEN ACROSS THE DELAWARE INTO SOUTHERN NEW JERSEY. THESE STORM MAY CONTAIN STRONG DAMAGING WIND GUSTS...HAIL AND HEAVY DOWNPOURS AS THEY MOVE THROUGH. DANGEROUS AND SOMETIMES DEADLY LIGHTNING IS A DEFINITE THREAT. A SEVERE THUNDERSTORM WATCH MEANS SEVERE THUNDERSTORMS ARE POSSIBLE. ISOLATED TORNADOES CANq ALSO DEVELOP WITHOUT WARNING UNDER THESE SITUATIONS. BE PREPARED TO SEEK SHELTER IF THREATENING WEATHER APPROACHES. FURTHER STATEMENTS OR WARNINGS WILL BE ISSUED AS NEEDED. NC
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 7, 11:10 AM EDT | Severe Thunderstorm Warning | PHI | Chester | 65 min |
| Jul 7, 11:52 AM EDT | Severe Thunderstorm Warning | PHI | Delaware | 53 min |
| Jul 7, 12:02 PM EDT | Severe Thunderstorm Warning | PHI | Philadelphia | 43 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; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.