Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2008
Severe Thunderstorm Warning 214, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 10, 2008, 11:09 AM EDT for 4 counties in Pennsylvania. It was in force for 66 min. 3 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 10, 2008, 11:09 AM EDT (15:09 UTC)
- Expired
- Aug 10, 2008, 12:15 PM EDT
- In force
- 66 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 88 km from the middle of the area, began a volume at 15:12 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 10, 11:10 AM EDT | HAIL 1.75 | 2 Se Exton, PA | |
| Aug 10, 11:15 AM EDT | HAIL 0.88 | Exton, PA | |
| Aug 10, 11:15 AM EDT | HAIL 2 | West Chester, PA |
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 10, 10:46 AM EDT | Severe Thunderstorm Watch | SPC | 10 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 3.2 hours before the alert went out and 214 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
- 771 J/kg
- Mixed-layer CIN
- -66 J/kg
- Mixed-layer LCL
- 923 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 3 m²/s²
- 0-3 km storm-relative helicity
- 85 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.8
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS51 KPHI 101509 SVRPHI PAC029-045-091-101-101615- /O.NEW.KPHI.SV.W.0214.080810T1509Z-080810T1615Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1109 AM EDT SUN AUG 10 2008 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA... DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA... MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA... CENTRAL PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA... * UNTIL 1215 PM EDT * AT 1103 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND DESTRUCTIVE WINDS IN EXCESS OF 70 MPH. THIS STORM WAS LOCATED NEAR GRADYVILLE...OR ABOUT 7 MILES EAST OF WEST CHESTER...AND MOVING NORTHEAST AT 22 MPH. * OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LIONVILLE...NEWTOWN SQUARE...BROOMALL...CHESTER SPRINGS...PAOLI... TROUT LAKE...RADNOR TOWNSHIP...BRYN MAWR...VALLEY FORGE... PHOENIXVILLE...KING OF PRUSSIA...NORRISTOWN...CHESTNUT HILL... COLLEGEVILLE...PLYMOUTH MEETING...AMBLER...WILLOW GROVE AND LANSDALE DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM. WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM. IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 PM SUNDAY EVENING FOR NORTHERN DELAWARE AND NEW JERSEY AND EASTERN PENNSYLVANIA. LAT...LON 4032 7539 4013 7509 3986 7542 3998 7579 TIME...MOT...LOC 1509Z 211DEG 19KT 3995 7546 $$ RNS
1 follow-up statement
000 WWUS51 KPHI 101540 SVSPHI SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1140 AM EDT SUN AUG 10 2008 PAC029-045-091-101-101615- /O.CON.KPHI.SV.W.0214.000000T0000Z-080810T1615Z/ DELAWARE PA-PHILADELPHIA PA-CHESTER PA-MONTGOMERY PA- 1139 AM EDT SUN AUG 10 2008 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1215 PM EDT FOR MONTGOMERY...EAST CENTRAL CHESTER...CENTRAL PHILADELPHIA AND NORTHERN DELAWARE COUNTIES... AT 1133 AM EDT...TRAINED WEATHER SPOTTERS REPORTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING GOLF BALL SIZE HAIL...AND DESTRUCTIVE WINDS IN EXCESS OF 70 MPH. THIS STORM WAS LOCATED NEAR DEVON-BERWYN...OR 11 MILES NORTHEAST OF WEST CHESTER...MOVING NORTHEAST AT 30 MPH. A SPOTTER IN WEST CHESTER REPORTED 2 INCH DIAMETER HAIL. OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO BRYN MAWR...SPRING CITY...ROYERSFORD...NARBERTH...KING OF PRUSSIA... AUDUBON...WEST CONSHOHOCKEN...CONSHOHOCKEN...BRIDGEPORT...WEST NORRITON...TRAPPE...COLLEGEVILLE...TROOPER...EAGLEVILLE... NORRISTOWN...EVANSBURG...PLYMOUTH MEETING...CHESTNUT HILL...EAST NORRITON...WYNDMOOR...SKIPPACK...FLOURTOWN...BLUE BELL...WYNCOTE... ORELAND...GLENSIDE...AMBLER...FORT WASHINGTON...KULPSVILLE... HARLEYSVILLE...NORTH WALES...SPRING HOUSE...MAPLE GLEN...LANSDALE AND WILLOW GROVE DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM. WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM. IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 PM EDT SUNDAY EVENING FOR NORTHERN DELAWARE AND NEW JERSEY AND EASTERN PENNSYLVANIA. LAT...LON 4032 7539 4013 7509 3989 7538 4007 7569 TIME...MOT...LOC 1539Z 221DEG 26KT 4006 7539 $$ RNS
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 10:18 AM EDT | Severe Thunderstorm Warning | PHI | Chester | 57 min |
| Aug 10, 10:44 AM EDT | Severe Thunderstorm Warning | PHI | Delaware | 61 min |
| Aug 10, 11:32 AM EDT | Areal Flood Advisory | PHI | Chester, Delaware | 3 hr |
| Aug 10, 11:46 AM EDT | Severe Thunderstorm Warning | PHI | Delaware | 59 min |
| Aug 10, 12:09 PM EDT | Tornado Warning | PHI | Delaware | 36 min |
| Aug 10, 12:17 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery | 4 hr |
| Aug 10, 12:21 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Lehigh, Montgomery | 84 min |
| Aug 10, 12:40 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 95 min |
| Aug 10, 1:05 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Carbon, Lehigh, Monroe, Northampton | 115 min |
| Aug 10, 1:10 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Montgomery | 65 min |
| Aug 10, 1:47 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Montgomery | 58 min |
| Aug 10, 3:05 PM EDT | Flash Flood Warning | PHI | Chester | 3 hr |
| Aug 10, 3:35 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 40 min |
| Aug 10, 4:45 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 75 min |
| Aug 10, 5:25 PM EDT | Areal Flood Advisory | PHI | Berks, Montgomery | 110 min |
| Aug 10, 5:45 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 75 min |
| Aug 10, 5:59 PM EDT | Areal Flood Advisory | PHI | Chester, Delaware | 2 hr |
| Aug 10, 6:45 PM EDT | Areal Flood Advisory | PHI | Philadelphia | 2 hr |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2008Every severe thunderstorm warning in 2008
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.