Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 90, NWS Philadelphia/Mount Holly

June 17, 2004Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 17, 2004, 2:40 PM EDT for Chester 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: Jun 17, 2004, 2:40 PM EDT (18:40 UTC)
Expired: Jun 17, 2004, 3:30 PM EDT
In force: 50 min
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 130 km from the middle of the area, began a volume at 18:44 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jun 17, 2:35 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.7 hours before the alert went out and 69 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 456 J/kg
Mixed-layer CIN: -16 J/kg
Mixed-layer LCL: 655 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 55 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000 
WUUS51 KPHI 171840 AAA
SVRPHI
PAC029-171930-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING...CORRECTED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
237 PM EDT THU JUN 17 2004

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA

* UNTIL 330 PM EDT

* AT 233 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED 9 MILES WEST OF HONEY BROOK...OR
  ABOUT 14 MILES NORTHEAST OF LANCASTER...AND MOVING SOUTHEAST AT 30
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HONEY BROOK BY 250 PM EDT
  PARKESBURG BY 300 PM EDT
  COATESVILLE BY 305 PM EDT
  DOWNINGTOWN BY 315 PM EDT
  WEST CHESTER AND 6 MILES NORTHEAST OF KENNETT SQUARE BY 325 PM EDT.

LAT...LON 4025 7609 4010 7621 3979 7575 3997 7549

$$

WN

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 17, 2:37 PM EDT	Severe Thunderstorm Warning	PHI	Chester	53 min
Jun 17, 5:23 PM EDT	Special Marine Warning	PHI		97 min
Jun 17, 5:58 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	32 min
Jun 17, 6:27 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh	33 min
Jun 17, 6:45 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Northampton	30 min
Jun 17, 7:08 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	52 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2004 Every 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; radar from the NEXRAD Level II archive.