Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009
Severe Thunderstorm Warning 127, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2009, 7:22 PM EDT for 5 counties in Pennsylvania. It was in force for 53 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 17, 2009, 7:22 PM EDT (23:22 UTC)
- Expired
- Jul 17, 2009, 8:15 PM EDT
- In force
- 53 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 77 km from the middle of the area, began a volume at 23:25 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 17, 7:25 PM EDT | TSTM WND DMG | Media, PA | TREES AND WIRES DOWN IN MEDIA, UPPER DARBY AND SPRINGFIELD. |
| Jul 17, 7:55 PM EDT | TSTM WND GST 46 | Philadelphia, PA | A 46 MPH THUNDERSTORM WIND GUST WAS MEASURED AT THE NORTHEAST PHILADELPHIA AIRPORT. |
| Jul 17, 8:09 PM EDT | TSTM WND DMG | Lansdale, PA | TREES DOWN. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 11.4 hours before the alert went out and 218 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
- 95 J/kg
- Mixed-layer CIN
- -122 J/kg
- Mixed-layer LCL
- 1120 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- -28 m²/s²
- 0-3 km storm-relative helicity
- 62 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.0
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS51 KPHI 172322 SVRPHI PAC017-029-045-091-101-180015- /O.NEW.KPHI.SV.W.0127.090717T2322Z-090718T0015Z/ BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 722 PM EDT FRI JUL 17 2009 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... SOUTHERN BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA... EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA... DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA... EASTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA... WESTERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA... THIS INCLUDES THE CITY OF PHILADELPHIA... * UNTIL 815 PM EDT * AT 719 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR SWARTHMORE...OR 12 MILES SOUTHWEST OF PHILADELPHIA...AND MOVING NORTH AT 35 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... BRYN MAWR...TROUT LAKE...MORRIS PARK AND ROXBOROUGH AROUND 730 PM EDT... PLYMOUTH MEETING...CHESTNUT HILL AND NORRISTOWN AROUND 740 PM EDT... AMBLER AROUND 750 PM EDT... LANSDALE AROUND 755 PM EDT... CHALFONT AROUND 805 PM EDT... PRECAUTIONARY/PREPAREDNESS ACTIONS... THIS IS A DANGEROUS STORM. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS. && LAT...LON 4040 7532 4028 7491 3986 7525 3987 7555 TIME...MOT...LOC 2321Z 202DEG 29KT 3994 7533 $$ KRUZDLO
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 17, 5:41 PM EDT | Severe Thunderstorm Warning | PHI | Northampton | 52 min |
| Jul 17, 6:10 PM EDT | Severe Thunderstorm Warning | PHI | Chester | 80 min |
| Jul 17, 7:07 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Lehigh, Montgomery | 53 min |
| Jul 17, 7:33 PM EDT | Areal Flood Advisory | PHI | Chester, Delaware, Montgomery, Philadelphia | 86 min |
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.