Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2002

Severe Thunderstorm Warning 40, NWS Philadelphia/Mount Holly

May 13, 2002Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 13, 2002, 2:41 PM EDT for Montgomery County, Pennsylvania. It was in force for 34 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 13, 2002, 2:41 PM EDT (18:41 UTC)
Expired: May 13, 2002, 3:15 PM EDT
In force: 34 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 86 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
May 13, 1:30 PM EDT	Tornado Watch	SPC	6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.7 hours before the alert went out and 224 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: 313 J/kg
Mixed-layer CIN: -110 J/kg
Mixed-layer LCL: 1186 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 117 m²/s²
0-3 km storm-relative helicity: 127 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.0

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 131841
SVRPHI
PAC091-131915-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
239 PM EDT MON MAY 13 2002

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA.
  
* UNTIL 315 PM EDT.

* AT 234 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM... 6 MILES NORTHWEST OF POTTSTOWN...MOVING EAST
  AT 50 MPH. THIS THUNDERSTORM APPEARS TO BE PRODUCING LARGE HAIL
  BETWEEN BIRDSBORO AND BECHTELSVILLE IN BERKS COUNTY.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  GILBERTSVILLE AT 245 PM.
  EAST GREENVILLE AT 250 PM.

HAIL UP TO ONE INCH IN DIAMETER AND WINDS GREATER THAN 55 MILES AN
HOUR ARE EXPECTED FROM THIS STORM. SEEK SHELTER IN A STURDY STRUCTURE
UNTIL THE STORM HAS PASSED.

A TORNADO WATCH IS ALSO IN EFFECT FOR THE WARNED AREA. REMEMBER...
SEVERE THUNDERSTORMS CAN PRODUCE TORNADOES WITH LITTLE OR NO ADVANCE
WARNING.

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
May 13, 2:18 PM EDT	Severe Thunderstorm Warning	PHI	Berks	42 min
May 13, 3:02 PM EDT	Severe Thunderstorm Warning	PHI	Berks	28 min
May 13, 3:08 PM EDT	Tornado Warning	PHI	Berks	37 min
May 13, 3:08 PM EDT	Tornado Warning	PHI	Berks	112 min
May 13, 3:21 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	24 min
May 13, 3:25 PM EDT	Flash Flood Warning	PHI	Berks	95 min
May 13, 4:40 PM EDT	Severe Thunderstorm Warning	PHI	Chester	65 min
May 13, 4:57 PM EDT	Flash Flood Warning	PHI	Berks	2 hr
May 13, 5:03 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	42 min
May 13, 5:16 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	39 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.