Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 1991
Severe Thunderstorm Warning 10, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 30, 1991, 5:55 PM EDT for Philadelphia County, Pennsylvania. It was in force for 35 min.
The area
The counties it named.
The facts
- Issued
- May 30, 1991, 5:55 PM EDT (21:55 UTC)
- Expired
- May 30, 1991, 6:30 PM EDT
- In force
- 35 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Whole counties
County Philadelphia County, PA
The nearest sounding before it
Atlantic City In, NJ (KACY), launched 12:00Z, 9.9 hours before the alert went out and 82 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
- 197 J/kg
- Mixed-layer CIN
- -139 J/kg
- Mixed-layer LCL
- 1366 m above ground
- 0-6 km bulk shear
- 19 kt
- 0-1 km storm-relative helicity
- 48 m²/s²
- 0-3 km storm-relative helicity
- 82 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 302159 COR SVRPHL PAC101-302230- BULLETIN - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE PHILADELPHIA PA 555 PM EDT THU MAY 30 1991 THE NATIONAL WEATHER SERVICE IN PHILADELPHIA HAS ISSUED A SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 630 PM EDT FOR PEOPLE IN THE FOLLOWING LOCATION... IN SOUTHEAST PENNSYLVANIA ...SOUTHERN PHILADELPHIA COUNTY AT 550 PM WEATHER SERVICE RADAR SHOWED A VERY INTENSE THUNDERSTORM OVER DELAWARE COUNTY. THIS THUNDERSTORM PRODUCED HAIL 1/2 TO 1 INCH IN DIAMETER AS IT MOVED THROUGH CHESTER COUNTY. THE THUNDERSTORM IS MOVING EAST AROUND 25 MPH AND WILL MOVE INTO PHILADELPHIA COUNTY AROUND 6 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. A SEVERE THUNDERSTORM WATCH CONTINUES FOR SOUTHEASTERN PENNSYLVANIA AND SOUTHERN NEW JERSEY UNTIL 9 PM EDT. REMEMBER SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES WITH LITTLE OR NO ADVANCED WARNING.
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, May 30, 4:36 PM EDT, 1 hour 19 minutes before
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
Special weather statement, May 30, 4:48 PM EDT, 1 hour 7 minutes before
DEZ003-302145- SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE WILMINGTON DE 444 PM EDT THU MAY 30 1991 ...SEVERE THUNDERSTORM WATCH FOR NORTHERN DELAWARE UNTIL 9PM... AT 435PM EDT WEATHER RADAR SHOWED SOME STRONG THUNDERSTORMS OVER SOUTHEASTERN PENNSYLVANIA MOVING TOWARD THE SOUTHEAST AT 30 MPH. THE STRONGEST THUNDERSTORMS WERE LOCATED 15 MILES NORTH OF MIDDLETOWN AND 20 MILES EAST OF LANCASTER. THE THUNDERSTORM EAST OF LANCASTER WILL LIKELY STAY NORTH OF WILMINGTON AND WAS HEADING TOWARD THE PHILADELPHIA COMPLEX. NO SEVERE WEATHER HAS BEEN REPORTED AS YET...BUT A SEVERE THUNDERSTORM WATCH IS IN EFFECT FOR NEW CASTLE COUNTY DELAWARE UNTIL 9PM TONIGHT. MORE ACTIVITY COULD THREATEN THE AREA DURING THE EVENING.
Special weather statement, May 30, 5:01 PM EDT, 54 minutes before
PAZ012-NJZ002>004-006-302300-
SPECIAL WEATHER STATEMENT - THUNDERSTORM IN CHESTER COUNTY
NATIONAL WEATHER SERVICE PHILADELPHIA PA
500 PM EDT THU MAY 30 1991
...SEVERE THUNDERSTORM WATCH TILL 9 PM EDT FOR SOUTHEASTERN
PENNSYLVANIA AND SOUTHERN NEW JERSEY EXCEPT CAPE MAY COUNTY...
...INTENSE THUNDERSTORM OVER NORTHERN CHESTER COUNTY PENNSYLVANIA...
AT 5 PM WEATHER SERVICE RADAR SHOWED AN INTENSE THUNDERSTORM
OVER NORTHERN CHESTER COUNTY PENNSYLVANIA. THIS THUNDERSTORM WAS
MOVING EAST AROUND 25 MPH AND MAY CAUSE STRONG GUSTY WINDS AND LOCALLY
HEAVY RAIN AS IT MOVES ACROSS THE NORTHERN HALF OF CHESTER COUNTY.
THERE WERE ALSO THUNDERSTORMS IN CENTRAL MONTGOMERY COUNTY
OF PENNSYLVANIA. THESE THUNDERSTORMS WERE ALSO MOVING EAST AROUND
25 MPH AND MAY CAUSE SOME LOCAL DOWNPOURS AND GUSTY WINDS.
REMEMBER A SEVERE THUNDERSTORM WATCH MEANS THAT CONDITIONS ARE
RIGHT FOR SEVERE THUNDERSTORMS TO DEVELOP.
STAY TUNED TO NOAA WEATHER RADIO OR YOUR LOCAL RADIO OR TV
STATION FOR ADDITIONAL INFORMATION AND FOR POSSIBLE WARNINGS.
REMEMBER...ALL THUNDERSTORMS ARE CAPABLE OF PRODUCING STRONG WIND
GUSTS...LIGHTNING...HEAVY DOWNPOURS...AND SMALL HAIL.
IF YOU OBSERVE THREATENING WEATHER...SEEK SHELTER AT ONCE.
SPSpecial weather statement, May 30, 5:26 PM EDT, 29 minutes before
PAZ011-016-310100 - SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE ALLENTOWN PA 525 PM EDT THU MAY 30 1991 ...SEVERE THUNDERSTORM WATCH FOR THE LEHIGH VALLEY AND POCONOS UNTIL 7 PM EDT TONIGHT... A SEVERE THUNDERSTORM CONTINUES FOR THE LEHIGH VALLEY AND POCONOS UNTIL 7 PM EDT TONIGHT. NATIONAL WEATHER SERVICE RADAR INDICATED SEVERAL HEAVY THUNDERSTORMS OCCURRING OVER MUCH OF SCHUYLKILL AND NORTHERN BERKS COUNTIES. THESE STORMS ARE MOVING TO THE SOUTHEAST AND WILL MOVE INTO BERKS...LEHIGH AND NORTHAMTON COUNTIES BY 6PM. THESE THUNDERSTORMS MAY CONTAIN HIGH WIND... HEAVY RAIN AND POSSIBLE HAIL AND DANGEROUS LIGHTNING. PERSONS IN THESE AREAS SHOULD BE ON THE ALERT FOR POSSIBLE SERVERE WEATHER OVER THE NEXT HOUR OR SO AND IF SIGHTED BE PREPARED TO MOVE TO A PLACE OF SAFETY IMMEDIATLY. BLACKBURN
Special weather statement, May 30, 5:28 PM EDT, 27 minutes before
PAZ011-016-310100 - SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE ALLENTOWN PA...CORRECTION 525 PM EDT THU MAY 30 1991 ...SEVERE THUNDERSTORM WATCH FOR THE LEHIGH VALLEY AND POCONOS UNTIL 7 PM EDT TONIGHT... A SEVERE THUNDERSTORM WATCH CONTINUES FOR THE LEHIGH VALLEY AND POCONOS UNTIL 7 PM EDT TONIGHT. NATIONAL WEATHER SERVICE RADAR INDICATED SEVERAL HEAVY THUNDERSTORMS OCCURRING OVER MUCH OF SCHUYLKILL AND NORTHERN BERKS COUNTIES. THESE STORMS ARE MOVING TO THE SOUTHEAST AND WILL MOVE INTO BERKS...LEHIGH AND NORTHAMTON COUNTIES BY 6PM. THESE THUNDERSTORMS MAY CONTAIN HIGH WIND... HEAVY RAIN AND POSSIBLE HAIL AND DANGEROUS LIGHTNING. PERSONS IN THESE AREAS SHOULD BE ON THE ALERT FOR POSSIBLE SERVERE WEATHER OVER THE NEXT HOUR OR SO AND IF SIGHTED BE PREPARED TO MOVE TO A PLACE OF SAFETY IMMEDIATLY. BLACKBURN
Special weather statement, May 30, 5:44 PM EDT, 11 minutes before
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
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 30, 5:29 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 46 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.