Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 87, NWS Philadelphia/Mount Holly

July 1, 2001Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 1, 2001, 6:31 PM EDT for Philadelphia County, Pennsylvania. It was in force for 29 min. 1 report 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: Jul 1, 2001, 6:31 PM EDT (22:31 UTC)
Expired: Jul 1, 2001, 7:00 PM EDT
In force: 29 min
Issued by: NWS Philadelphia/Mount Holly
Area: Whole counties

County Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 62 km from the middle of the area, began a volume at 22:31 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.

What was reported inside it

Time	Report	Where	Remark
Jul 1, 6:35 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
Jul 1, 4:30 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.5 hours before the alert went out and 214 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: 301 J/kg
Mixed-layer CIN: -117 J/kg
Mixed-layer LCL: 1284 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 104 m²/s²
0-3 km storm-relative helicity: 132 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 012232
SVRPHI

PAC101-012300-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
631 PM EDT SUN JUL 1 2001

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA.

* UNTIL 700 PM EDT.

* AT 626 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  DEVELOPING SEVERE THUNDERSTORM... 7 MILES SOUTHWEST OF PHILADELPHIA...
  MOVING EAST AT 30 MPH.

*  HAIL...DIME SIZED OR GREATER...IS EXPECTED FROM THIS STORM. IF 
   YOU ARE IN THE STORM'S PATH...SEEK SHELTER INDOORS...ALONG WITH 
   TORRENTIAL DOWNPOURS AND POSSIBLY SOME STRONG GUSTY WINDS.

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
Jun 30, 10:53 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	52 min
Jul 1, 1:09 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	36 min
Jul 1, 1:20 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	25 min
Jul 1, 1:26 PM EDT	Severe Thunderstorm Warning	PHI	Berks	64 min
Jul 1, 2:03 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	42 min
Jul 1, 2:44 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Northampton	61 min
Jul 1, 4:06 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	39 min
Jul 1, 4:35 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Montgomery	40 min
Jul 1, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	45 min
Jul 1, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Montgomery	45 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; radar from the NEXRAD Level II archive.