Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011
Severe Thunderstorm Warning 187, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 23, 2011, 7:55 PM EDT for Chester County, Delaware County, Montgomery County, Pennsylvania. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.
The area
The outline as issued.
The facts
- Issued
- Jul 23, 2011, 7:55 PM EDT (23:55 UTC)
- Expired
- Jul 23, 2011, 8:25 PM EDT
- In force
- 30 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Chester County, PA, Delaware County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 100 km from the middle of the area, began a volume at 23:59 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.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 11.9 hours before the alert went out and 203 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
- 758 J/kg
- Mixed-layer CIN
- -177 J/kg
- Mixed-layer LCL
- 1647 m above ground
- 0-6 km bulk shear
- 20 kt
- 0-1 km storm-relative helicity
- 8 m²/s²
- 0-3 km storm-relative helicity
- 23 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
744 WUUS51 KPHI 232355 SVRPHI PAC029-045-091-240100- /O.NEW.KPHI.SV.W.0187.110723T2355Z-110724T0100Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 755 PM EDT SAT JUL 23 2011 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... NORTHERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA... NORTH CENTRAL DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA... CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA... * UNTIL 900 PM EDT * AT 750 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR GLENMOORE...OR 15 MILES NORTHWEST OF WEST CHESTER...AND MOVING EAST AT 15 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... GLENMOORE AROUND 805 PM EDT... DOWNINGTOWN AROUND 815 PM EDT... LIONVILLE AND PUGHTOWN AROUND 825 PM EDT... CHESTER SPRINGS AROUND 830 PM EDT... PHOENIXVILLE AROUND 850 PM EDT... PAOLI AROUND 855 PM EDT... PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER... PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS. PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY. && LAT...LON 4022 7534 3998 7531 3997 7592 4012 7592 TIME...MOT...LOC 2355Z 267DEG 15KT 4008 7581 $$ HAYES
2 follow-up statements
270 WWUS51 KPHI 240014 SVSPHI SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 814 PM EDT SAT JUL 23 2011 PAC029-045-091-240100- /O.CON.KPHI.SV.W.0187.000000T0000Z-110724T0100Z/ DELAWARE PA-CHESTER PA-MONTGOMERY PA- 814 PM EDT SAT JUL 23 2011 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT FOR CENTRAL MONTGOMERY...NORTHEASTERN CHESTER AND NORTH CENTRAL DELAWARE COUNTIES... AT 811 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR LIONVILLE...OR 10 MILES NORTHWEST OF WEST CHESTER... MOVING EAST AT 15 MPH. THE SEVERE THUNDERSTORM WILL BE NEAR... LIONVILLE BY 825 PM EDT... CHESTER SPRINGS AND EXTON BY 830 PM EDT... PHOENIXVILLE AND MALVERN BY 850 PM EDT... VALLEY FORGE AND PAOLI BY 855 PM EDT... VALLEY FORGE...CHESTERBROOK AND AUDUBON BY 900 PM EDT... PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS IN ELVERSON. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS! PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY. && LAT...LON 4001 7574 4015 7577 4022 7534 3998 7531 TIME...MOT...LOC 0014Z 267DEG 15KT 4008 7571 $$ HAYES
088 WWUS51 KPHI 240025 SVSPHI SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 825 PM EDT SAT JUL 23 2011 PAC029-045-091-240035- /O.CAN.KPHI.SV.W.0187.000000T0000Z-110724T0100Z/ DELAWARE PA-CHESTER PA-MONTGOMERY PA- 825 PM EDT SAT JUL 23 2011 ...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL MONTGOMERY... NORTHEASTERN CHESTER AND NORTH CENTRAL DELAWARE COUNTIES IS CANCELLED... THE STORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO LONGER PRODUCING SEVERE WEATHER. PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY. LAT...LON 4001 7574 4015 7577 4022 7534 3998 7531 TIME...MOT...LOC 0025Z 267DEG 15KT 4008 7565 $$ HAYES
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 23, 6:48 PM EDT | Special Weather Statement | PHI | Chester | 57 min |
| Jul 23, 7:32 PM EDT | Special Weather Statement | PHI | Chester | 58 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2011Every severe thunderstorm warning in 2011
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; radar from the NEXRAD Level II archive.