Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 148, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 29, 2009, 11:48 AM EDT for Bucks County, Chester County, Montgomery County, Pennsylvania. It was in force for 72 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
- Jul 29, 2009, 11:48 AM EDT (15:48 UTC)
- Expired
- Jul 29, 2009, 1:00 PM EDT
- In force
- 72 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Bucks County, PA, Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 91 km from the middle of the area, began a volume at 15:49 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 |
|---|---|---|---|
| Jul 29, 12:06 PM EDT | HAIL 1.5 | 4 N Valley Forge, PA | PING PONG SIZE HAIL REPORT IN UPPER PROVIDENCE TWP |
| Jul 29, 12:15 PM EDT | TSTM WND DMG | Royersford, PA | LARGE TREES DOWN |
| Jul 29, 12:50 PM EDT | TSTM WND DMG | Perkasie, PA | TREES DOWN ON HIGHLAND AVENUE IN HILLTOWN AND RIVER ROAD AND FLEECEY DALE ROAD IN SOLEBURY. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 3.8 hours before the alert went out and 116 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
- 1577 J/kg
- Mixed-layer CIN
- -35 J/kg
- Mixed-layer LCL
- 745 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 56 m²/s²
- 0-3 km storm-relative helicity
- 86 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.3
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS51 KPHI 291548 SVRPHI PAC017-029-091-291700- /O.NEW.KPHI.SV.W.0148.090729T1548Z-090729T1700Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1148 AM EDT WED JUL 29 2009 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA... NORTHEASTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA... MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA... * UNTIL 100 PM EDT * AT 1147 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR CHESTER SPRINGS...OR 10 MILES NORTH OF WEST CHESTER...AND MOVING NORTHEAST AT 30 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... VALLEY FORGE AROUND 1155 AM EDT... ROYERSFORD AROUND NOON EDT... TRAPPE AND COLLEGEVILLE AROUND 1205 PM EDT... SCHWENKSVILLE AROUND 1215 PM EDT... LANSDALE AROUND 1225 PM EDT... SOUDERTON AND HATFIELD AROUND 1230 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. 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 GREATEST KILLERS. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. && LAT...LON 4059 7524 4028 7491 4004 7561 4019 7574 TIME...MOT...LOC 1548Z 224DEG 25KT 4011 7560 $$ TFG
3 follow-up statements
000
WWUS51 KPHI 291610
SVSPHI
SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1210 PM EDT WED JUL 29 2009
PAC029-291619-
/O.CAN.KPHI.SV.W.0148.000000T0000Z-090729T1700Z/
CHESTER PA-
1210 PM EDT WED JUL 29 2009
...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...
THE SEVERE THUNDERSTORM IN NOW IN MONTGOMERY COUNTY.
LAT...LON 4028 7491 4009 7546 4013 7548 4012 7550
4014 7551 4015 7551 4015 7553 4018 7556
4020 7556 4020 7558 4025 7563 4059 7524
TIME...MOT...LOC 1609Z 229DEG 22KT 4017 7548
$$
PAC017-091-291700-
/O.CON.KPHI.SV.W.0148.000000T0000Z-090729T1700Z/
MONTGOMERY PA-BUCKS PA-
1210 PM EDT WED JUL 29 2009
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 PM EDT
FOR BUCKS AND MONTGOMERY COUNTIES...
AT 1209 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING HAIL AS
LARGE AS GOLF BALL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.
THIS STORM WAS LOCATED NEAR COLLEGEVILLE...OR 16 MILES NORTHEAST OF
WEST CHESTER...MOVING NORTHEAST AT 25 MPH.
PING PONG BALL SIZE HAIL WAS REPORTED IN UPPER PROVIDENCE TOWNSHIP.
THE SEVERE THUNDERSTORM WILL BE NEAR...
COLLEGEVILLE BY 1215 PM EDT...
SCHWENKSVILLE BY 1220 PM EDT...
HATFIELD AND LANSDALE BY 1235 PM EDT...
SOUDERTON BY 1240 PM EDT...
FRICKS AND CHALFONT BY 1245 PM EDT...
CHALFONT AND PERKASIE BY 1250 PM EDT...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
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.
THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS
&&
LAT...LON 4028 7491 4009 7546 4013 7548 4012 7550
4014 7551 4015 7551 4015 7553 4018 7556
4020 7556 4020 7558 4025 7563 4059 7524
TIME...MOT...LOC 1609Z 229DEG 22KT 4017 7548
$$
TFG000 WWUS51 KPHI 291643 SVSPHI SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1243 PM EDT WED JUL 29 2009 PAC091-291652- /O.CAN.KPHI.SV.W.0148.000000T0000Z-090729T1700Z/ MONTGOMERY PA- 1243 PM EDT WED JUL 29 2009 ...THE SEVERE THUNDERSTORM WARNING FOR MONTGOMERY COUNTY IS CANCELLED... LAT...LON 4028 7491 4022 7516 4037 7541 4053 7518 TIME...MOT...LOC 1642Z 237DEG 24KT 4030 7525 $$ PAC017-291700- /O.CON.KPHI.SV.W.0148.000000T0000Z-090729T1700Z/ BUCKS PA- 1243 PM EDT WED JUL 29 2009 ...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 100 PM EDT FOR CENTRAL BUCKS COUNTY... AT 1240 PM EDT...A SEVERE THUNDERSTORM WAS REPORTED CAPABLE OF PRODUCING PENNY SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR FRICKS...OR 21 MILES NORTH OF PHILADELPHIA...MOVING NORTHEAST AT 25 MPH. THE SEVERE THUNDERSTORM WILL BE NEAR... NEW BRITAIN AND DUBLIN BY 1250 PM EDT... DOYLESTOWN AND BEDMINSTER BY 1255 PM EDT... GARDENVILLE...PIPERSVILLE...6 MILES SOUTH OF TINICUM AND 8 MILES SOUTH OF OTTSVILLE BY 100 PM EDT... PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS STORM HAS A HISTORY OF PRODUCING HAIL UP TO PING-PONG BALL SIZE. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS && LAT...LON 4028 7491 4022 7516 4037 7541 4053 7518 TIME...MOT...LOC 1642Z 237DEG 24KT 4030 7525 $$ AMC
000 WWUS51 KPHI 291701 SVSPHI SEVERE WEATHER STATEMENT NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 101 PM EDT WED JUL 29 2009 PAC017-291710- /O.EXP.KPHI.SV.W.0148.000000T0000Z-090729T1700Z/ BUCKS PA- 101 PM EDT WED JUL 29 2009 ...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL BUCKS COUNTY HAS EXPIRED... THE THUNDERSTORMS WHICH PROMPTED THE WARNING FOR BUCKS COUNTY ARE NOW MOVING NORTHEAST ACROSS THE DELAWARE RIVER INTO NEW JERSEY. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT WEDNESDAY EVENING FOR NORTHWESTERN NEW JERSEY AND EASTERN PENNSYLVANIA. LAT...LON 4028 7491 4022 7516 4037 7541 4053 7518 TIME...MOT...LOC 1700Z 237DEG 24KT 4037 7512 $$ AMC
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 29, 10:15 AM EDT | Flash Flood Watch | PHI | Berks, Delaware, Lehigh, Northampton, Philadelphia | 17 hr |
| Jul 29, 12:12 PM EDT | Severe Thunderstorm Warning | PHI | Carbon, Lehigh, Monroe, Northampton | 78 min |
| Jul 29, 1:51 PM EDT | Flash Flood Warning | PHI | Carbon, Monroe | 9 hr |
| Jul 29, 1:56 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 64 min |
| Jul 29, 2:04 PM EDT | Severe Thunderstorm Warning | PHI | Monroe | 56 min |
| Jul 29, 2:11 PM EDT | Tornado Warning | PHI | Carbon, Monroe | 34 min |
| Jul 29, 2:32 PM EDT | Flash Flood Warning | PHI | Monroe | 6 hr |
| Jul 29, 5:09 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 66 min |
| Jul 29, 5:28 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Northampton | 40 min |
| Jul 29, 5:55 PM EDT | Areal Flood Advisory | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2009Every severe thunderstorm warning in 2009
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.