Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2004
Severe Thunderstorm Warning 193, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 21, 2004, 12:55 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 50 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
- Aug 21, 2004, 12:55 PM EDT (16:55 UTC)
- Expired
- Aug 21, 2004, 1:45 PM EDT
- In force
- 50 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Counties, with a storm outline in the text
Counties Chester County, PA, Montgomery County, PA
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 4.9 hours before the alert went out and 210 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
- 545 J/kg
- Mixed-layer CIN
- -109 J/kg
- Mixed-layer LCL
- 1174 m above ground
- 0-6 km bulk shear
- 38 kt
- 0-1 km storm-relative helicity
- 74 m²/s²
- 0-3 km storm-relative helicity
- 107 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 0.6
The text
As transmitted, in the capitals the NWS used until 2016.
000 WUUS51 KPHI 211655 SVRPHI PAC029-091-211745- BULLETIN - EAS ACTIVATION REQUESTED SEVERE THUNDERSTORM WARNING NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1255 PM EDT SAT AUG 21 2004 THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A * SEVERE THUNDERSTORM WARNING FOR... MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA. CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA. * UNTIL 145 PM EDT * AT 1253 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM. THIS STORM WAS LOCATED 7 MILES WEST OF PHOENIXVILLE...OR ABOUT 20 MILES SOUTHEAST OF READING...AND MOVING EAST AT 35 MPH. * THE SEVERE THUNDERSTORM WILL BE NEAR... PHOENIXVILLE BY 100 PM EDT... COLLEGEVILLE AND SPRING MOUNT BY 110 PM EDT... 8 MILES NORTH OF NORRISTOWN BY 115 PM EDT... 8 MILES NORTH OF AMBLER BY 125 PM EDT... LAT...LON 4018 7570 4004 7561 4016 7519 4036 7549 $$ JJM
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 21, 1:15 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 30 min |
| Aug 21, 5:14 PM EDT | Special Marine Warning | PHI | 76 min | |
| Aug 21, 5:14 PM EDT | Special Marine Warning | PHI | 76 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2004Every severe thunderstorm warning in 2004
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.