Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 75, NWS Philadelphia/Mount Holly

May 31, 2002Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 31, 2002, 4:31 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 29 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: May 31, 2002, 4:31 PM EDT (20:31 UTC)
Expired: May 31, 2002, 5:00 PM EDT
In force: 29 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 99 km from the middle of the area, began a volume at 20:31 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.5 hours before the alert went out and 203 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: 430 J/kg
Mixed-layer CIN: -126 J/kg
Mixed-layer LCL: 1001 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 106 m²/s²
0-3 km storm-relative helicity: 111 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

576 
WUUS51 KPHI 312031
SVRPHI
PAC029-091-312100-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
431 PM EDT FRI MAY 31 2002

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 500 PM EDT.

* AT 431 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM... 4 MILES SOUTH OF POTTSTOWN...MOVING EAST AT
  30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PHOENIXVILLE AT 440 PM.
  COLLEGEVILLE...SPRING MOUNT AT 445 PM.

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

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM FRIDAY
EVENING FOR NORTHEAST PENNSYLVANIA.

$$

LAT...LON 4028 7569 4013 7568 4012 7537 4028 7536

The office that day

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

Issued	Product	Office	Counties	Lasted
May 31, 5:04 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	26 min
May 31, 5:18 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	27 min
May 31, 5:30 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	45 min
May 31, 5:43 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	47 min
May 31, 7:30 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	45 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2002 Every severe thunderstorm warning in 2002

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.