Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2006

Severe Thunderstorm Warning 173, NWS Philadelphia/Mount Holly

July 18, 2006Philadelphia County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 18, 2006, 7:25 PM EDT for Philadelphia County, Pennsylvania. It was in force for 65 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 18, 2006, 7:25 PM EDT (23:25 UTC)
Expired: Jul 18, 2006, 8:30 PM EDT
In force: 65 min
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

County Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 23:25 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 18, 7:43 PM EDT	TSTM WND DMG	Philadelphia, PA	TREES DOWN IN ROXBOROUGH WITH 68 MPH WIND GUST.
Jul 18, 7:43 PM EDT	TSTM WND DMG	Philadelphia, PA	TREES DOWN IN ROXBOROUGH WITH A 68 MPH WIND GUST REPORTED.
Jul 18, 7:59 PM EDT	TSTM WND GST 48	Philadelphia, PA	A 48 MPH THUNDERSTORM WIND GUST WAS MEASURED AT THE PHILADELPHIA INTERNATIONAL AIRPORT. ALSO, HALF INCH HAIL WAS REPORTED BY THE AIRPORT WEATHER OBSERVER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

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 18, 12:38 PM EDT	Severe Thunderstorm Watch	SPC	7 hr
Jul 18, 6:37 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.4 hours before the alert went out and 101 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: 1100 J/kg
Mixed-layer CIN: -174 J/kg
Mixed-layer LCL: 1804 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -17 m²/s²
0-3 km storm-relative helicity: 16 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.

000 
WUUS51 KPHI 182326
SVRPHI
PAC101-190030-
/O.NEW.KPHI.SV.W.0173.060718T2325Z-060719T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
725 PM EDT TUE JUL 18 2006

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA
  THIS INCLUDES THE CITY OF PHILADELPHIA

* UNTIL 830 PM EDT

* AT 717 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 21
  MILES WEST OF PHILADELPHIA...OR ABOUT 13 MILES NORTHWEST OF
  SPRINGFIELD...AND MOVING EAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PHILADELPHIA BY 805 PM EDT...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

WIND DAMAGE WITH THIS STORM WILL OCCUR WELL AHEAD OF ANY RAIN OR
LIGHTNING. DO NOT WAIT FOR THE SOUND OF THUNDER BEFORE TAKING COVER.
SEEK SHELTER IMMEDIATELY INSIDE A STURDY STRUCTURE AND STAY AWAY FROM
WINDOWS.

LAT...LON 4005 7519 3996 7527 3991 7517 4011 7498

$$

AMC/MPD

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 18, 4:51 PM EDT	Severe Thunderstorm Warning	PHI	Berks	56 min
Jul 18, 5:33 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh, Northampton	57 min
Jul 18, 6:27 PM EDT	Severe Thunderstorm Warning	PHI	Chester	78 min
Jul 18, 7:09 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Montgomery	81 min
Jul 18, 7:37 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	53 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2006 Every severe thunderstorm warning in 2006

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.