Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2011
Severe Thunderstorm Warning 283, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 21, 2011, 1:47 PM EDT for Burlington County, Camden County, Mercer County, New Jersey; 5 counties in Pennsylvania. It was in force for 58 min. 6 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Aug 21, 2011, 1:47 PM EDT (17:47 UTC)
- Expired
- Aug 21, 2011, 2:45 PM EDT
- In force
- 58 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Burlington County, NJ, Camden County, NJ, Mercer County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 66 km from the middle of the area, began a volume at 17:49 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 |
|---|---|---|---|
| Aug 21, 2:45 PM EDT | TSTM WND DMG | Northeast Philadelphia, PA | TREES AND WIRES DOWN IN NORTHEAST PHILADELPHIA |
| Aug 21, 2:45 PM EDT | HAIL 0.25 | Philadelphia, PA | |
| Aug 21, 2:50 PM EDT | HAIL 0.75 | Riverton, NJ | |
| Aug 21, 2:50 PM EDT | HAIL 0.88 | Feasterville, PA | |
| Aug 21, 2:52 PM EDT | TSTM WND DMG | Feasterville, PA | TREES AND WIRES DOWN IN FEASTERVILLE |
| Aug 21, 2:55 PM EDT | TSTM WND DMG | Bensalem, PA | WIRES DOWN IN BENSALEM |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 21, 12:52 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 5.8 hours before the alert went out and 215 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
- 874 J/kg
- Mixed-layer CIN
- -29 J/kg
- Mixed-layer LCL
- 857 m above ground
- 0-6 km bulk shear
- 22 kt
- 0-1 km storm-relative helicity
- 55 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
962 WUUS51 KPHI 211747 SVRPHI NJC005-007-021-PAC017-029-045-091-101-211845- /O.NEW.KPHI.SV.W.0283.110821T1747Z-110821T1845Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 147 PM EDT SUN AUG 21 2011 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... CENTRAL MERCER COUNTY IN CENTRAL NEW JERSEY... THIS INCLUDES THE CITY OF TRENTON... SOUTHERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA... EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA... THIS INCLUDES THE CITY OF WEST CHESTER... DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA... SOUTHERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA... PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA... THIS INCLUDES THE CITY OF PHILADELPHIA... NORTHWESTERN BURLINGTON COUNTY IN SOUTHERN NEW JERSEY... NORTHWESTERN CAMDEN COUNTY IN SOUTHERN NEW JERSEY... THIS INCLUDES THE CITY OF CAMDEN... * UNTIL 245 PM EDT * AT 145 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM CHALFONT TO WEST CHESTER IN PENNSYLVANIA...AND MOVING EAST AT 40 MPH. * SEVERE THUNDERSTORMS WILL BE NEAR... CONCORDVILLE AROUND 150 PM EDT... DOYLESTOWN...CHEYNEY...NORRISTOWN AND KING OF PRUSSIA AROUND 155 PM EDT... AMBLER...GRADYVILLE AND LIMA AROUND 200 PM EDT... SWARTHMORE AND NETHER PROVIDENCE TOWNSHIP AROUND 205 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. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT SUNDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND EASTERN PENNSYLVANIA. && LAT...LON 3987 7505 3988 7586 4033 7525 4032 7464 TIME...MOT...LOC 1746Z 256DEG 33KT 4027 7521 3996 7562 $$ IOVINO
1 follow-up statement
826
WWUS51 KPHI 211815
SVSPHI
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
215 PM EDT SUN AUG 21 2011
NJC005-007-021-PAC017-029-045-091-101-211845-
/O.CON.KPHI.SV.W.0283.000000T0000Z-110821T1845Z/
CAMDEN NJ-MERCER NJ-DELAWARE PA-PHILADELPHIA PA-CHESTER PA-
MONTGOMERY PA-BUCKS PA-BURLINGTON NJ-
215 PM EDT SUN AUG 21 2011
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR NORTHWESTERN BURLINGTON...SOUTHERN BUCKS...SOUTHEASTERN
MONTGOMERY...EAST CENTRAL CHESTER...PHILADELPHIA...DELAWARE...CENTRAL
MERCER AND NORTHWESTERN CAMDEN COUNTIES...
AT 210 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER
SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM DOYLESTOWN TO CHEYNEY IN
PENNSYLVANIA...MOVING EAST AT 40 MPH.
SEVERE THUNDERSTORMS WILL BE NEAR...
ROSE VALLEY...NETHER PROVIDENCE TOWNSHIP...NEWTOWN SQUARE AND UPPER
PROVIDENCE TOWNSHIP BY 220 PM EDT...
WOODLYN...SWARTHMORE...RUTLEDGE AND RIDLEY PARK BY 225 PM EDT...
PHILADELPHIA INTERNATIONAL AIRPORT AND SHARON HILL BY 230 PM EDT...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.
PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.
A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.
&&
LAT...LON 3987 7505 3987 7514 3988 7515 3987 7519
3988 7568 4000 7570 4033 7525 4032 7464
TIME...MOT...LOC 1815Z 256DEG 33KT 4028 7505 3997 7547
$$
IOVINOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 3:24 AM EDT | Small Craft Advisory | PHI | 30 hr | |
| Aug 21, 3:28 AM EDT | Flash Flood Watch | PHI | Burlington, Camden, Cumberland, Gloucester, Hunterdon, Mercer and 6 more | 17 hr |
| Aug 21, 8:41 AM EDT | Special Weather Statement | PHI | Salem | 64 min |
| Aug 21, 10:33 AM EDT | Special Marine Warning | PHI | 57 min | |
| Aug 21, 11:07 AM EDT | Special Marine Warning | PHI | 83 min | |
| Aug 21, 12:20 PM EDT | Special Weather Statement | PHI | Morris | 55 min |
| Aug 21, 12:33 PM EDT | Severe Thunderstorm Warning | PHI | Morris | 33 min |
| Aug 21, 12:39 PM EDT | Special Weather Statement | PHI | Burlington, Camden | 66 min |
| Aug 21, 2:33 PM EDT | Areal Flood Advisory | PHI | Burlington, Camden, Mercer | 117 min |
| Aug 21, 2:43 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Camden, Gloucester, Mercer | 62 min |
| Aug 21, 3:08 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Mercer, Middlesex, Monmouth, Ocean | 67 min |
| Aug 21, 3:21 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth, Ocean | 54 min |
| Aug 21, 3:22 PM EDT | Special Marine Warning | PHI | 83 min | |
| Aug 21, 3:46 PM EDT | Flash Flood Warning | PHI | Burlington | 2 hr |
| Aug 21, 4:14 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth, Ocean | 46 min |
| Aug 21, 4:26 PM EDT | Special Marine Warning | PHI | 57 min | |
| Aug 21, 4:35 PM EDT | Areal Flood Advisory | PHI | Burlington, Camden, Mercer, Middlesex, Monmouth, Ocean | 3 hr |
| Aug 21, 5:44 PM EDT | Special Weather Statement | PHI | Mercer | 61 min |
| Aug 21, 6:05 PM EDT | Flash Flood Warning | PHI | Burlington | 6 hr |
| Aug 21, 6:12 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Mercer, Middlesex, Monmouth, Ocean | 63 min |
| Aug 21, 6:20 PM EDT | Special Weather Statement | PHI | Hunterdon | 55 min |
| Aug 21, 6:54 PM EDT | Areal Flood Advisory | PHI | Hunterdon, Middlesex, Morris, Somerset, Sussex, Warren | 111 min |
| Aug 21, 7:08 PM EDT | Special Weather Statement | PHI | Hunterdon, Middlesex, Somerset | 52 min |
| Aug 21, 7:18 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth, Ocean | 42 min |
| Aug 21, 7:21 PM EDT | Special Marine Warning | PHI | 84 min | |
| Aug 21, 7:24 PM EDT | Flash Flood Warning | PHI | Mercer, Monmouth, Ocean | 5 hr |
| Aug 21, 7:35 PM EDT | Areal Flood Advisory | PHI | Burlington, Mercer, Middlesex, Monmouth, Ocean | 115 min |
| Aug 21, 1:11 PM EDT | Special Weather Statement | PHI | Montgomery | 64 min |
| Aug 21, 1:25 PM EDT | Areal Flood Advisory | PHI | Bucks, Chester, Montgomery | 110 min |
| Aug 21, 3:31 PM EDT | Flash Flood Warning | PHI | Philadelphia | 8 hr |
| Aug 21, 4:11 PM EDT | Special Weather Statement | PHI | Carbon, Monroe | 64 min |
| Aug 21, 4:19 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe | 3 hr |
| Aug 21, 4:53 PM EDT | Special Weather Statement | PHI | Lehigh, Northampton | 67 min |
| Aug 21, 6:41 PM EDT | Special Weather Statement | PHI | Berks | 64 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2011Severe Thunderstorm Warnings in New Jersey, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.