Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 13, NWS Philadelphia/Mount Holly

April 9, 2001Delaware County, Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 9, 2001, 8:37 PM EDT for Delaware County, Philadelphia County, Pennsylvania. It was in force for 38 min. 2 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued: Apr 9, 2001, 8:37 PM EDT (00:37 UTC)
Expired: Apr 9, 2001, 9:15 PM EDT
In force: 38 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

Counties Delaware County, PA, Philadelphia County, PA

What was reported inside it

Time	Report	Where	Remark
Apr 9, 8:40 PM EDT	Thunderstorm Wind 52 E	Countywide, PA
Apr 9, 8:45 PM EDT	Thunderstorm Wind 50 E	Philadelphia, PA

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The watch it was issued in

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

Issued	Product	Office	Lasted
Apr 9, 7:00 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.6 hours before the alert went out and 215 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: 616 J/kg
Mixed-layer CIN: -34 J/kg
Mixed-layer LCL: 2415 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 177 m²/s²
0-3 km storm-relative helicity: 248 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 100039
SVRPHL
DEC003-MDC029-NJC019-021-PAC045-101-100115-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
837 PM EDT MON APR 9 2001

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  MERCER COUNTY IN CENTRAL NEW JERSEY.
  KENT COUNTY IN NORTHEAST MARYLAND.
  NEW CASTLE COUNTY IN NORTHERN DELAWARE.
  HUNTERDON COUNTY IN NORTHWEST NEW JERSEY.
  DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA.
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA.

* UNTIL 915 PM EDT.

* AT 834 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  SEVERE THUNDERSTORMS... 5 MILES WEST OF PHILADELPHIA...MOVING 
  EAST AT 60 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  TRENTON...LAWRENCEVILLE AT 845 PM.

FOR THE LATEST STORM INFORMATION...PLEASE TUNE TO NOAA WEATHER
RADIO...YOUR LOCAL RADIO OR TELEVISION STATION...OR YOUR CABLE
TELEVISION OUTLET.

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 9, 8:02 PM EDT	Severe Thunderstorm Warning	PHI	Chester	43 min
Apr 9, 8:09 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	36 min
Apr 9, 8:09 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	36 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2001 Every severe thunderstorm warning in 2001

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.