Alert archive / Pennsylvania / Tornado Warnings in 2007

Tornado Warning 3, NWS Philadelphia/Mount Holly

August 17, 2007Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this tornado warning at Aug 17, 2007, 2:14 PM EDT for Chester County, Pennsylvania. It was in force for 46 min. 1 report 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: Aug 17, 2007, 2:14 PM EDT (18:14 UTC)
Expired: Aug 17, 2007, 3:00 PM EDT
In force: 46 min
Issued by: NWS Philadelphia/Mount Holly
Area: Counties, with a storm outline in the text

County Chester County, PA

What was reported inside it

Time	Report	Where	Remark
Aug 17, 2:15 PM EDT	TSTM WND DMG	Coatesville, PA	SCATTERED LARGE TREE LIMBS DOWN ACROSS THE CENTRAL PART OF THE COUNTY.

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
Aug 17, 1:37 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.2 hours before the alert went out and 188 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: 352 J/kg
Mixed-layer CIN: -115 J/kg
Mixed-layer LCL: 1022 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 24 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

000 
WFUS51 KPHI 171814
TORPHI
PAC029-171900-
/O.NEW.KPHI.TO.W.0003.070817T1814Z-070817T1900Z/

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
214 PM EDT FRI AUG 17 2007

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 300 PM EDT

* AT 213 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR            
  MARSHALLTON...MOVING EAST AT 40   MPH.

* THE TORNADO WILL BE NEAR...
  MARSHALLTON BY 220 PM EDT...
  WEST CHESTER BY 225 PM EDT...
  WESTTOWN BY 230 PM EDT...

THE SAFEST PLACE TO BE DURING A TORNADO IS IN A BASEMENT. GET UNDER A
WORKBENCH OR OTHER PIECE OF STURDY FURNITURE. IF NO BASEMENT IS
AVAILABLE...SEEK SHELTER ON THE LOWEST FLOOR OF THE BUILDING IN AN
INTERIOR HALLWAY OR ROOM SUCH AS A CLOSET. USE BLANKETS OR PILLOWS TO
COVER YOUR BODY AND ALWAYS STAY AWAY FROM WINDOWS.

IF IN MOBILE HOMES OR VEHICLES...EVACUATE THEM AND GET INSIDE A
SUBSTANTIAL SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE
NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT FRIDAY
EVENING FOR NORTHERN DELAWARE AND NEW JERSEY AND EASTERN
PENNSYLVANIA.

LAT...LON 4000 7588 4002 7544 4000 7546 3999 7545
      3992 7555 3992 7556 3991 7556 3984 7566
      3982 7588
TIME...MOT...LOC 1814Z 271DEG 35KT 3991 7575

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 17, 1:48 PM EDT	Severe Thunderstorm Warning	PHI	Chester	72 min
Aug 17, 2:07 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	68 min
Aug 17, 2:19 PM EDT	Tornado Warning	PHI	Carbon	26 min
Aug 17, 2:20 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	70 min
Aug 17, 2:36 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	54 min
Aug 17, 2:41 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	79 min
Aug 17, 2:43 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	62 min
Aug 17, 2:45 PM EDT	Tornado Warning	PHI	Carbon, Northampton	45 min
Aug 17, 2:54 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh	66 min
Aug 17, 4:42 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	19 min
Aug 17, 4:45 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	60 min
Aug 17, 4:51 PM EDT	Severe Thunderstorm Warning	PHI	Lehigh, Northampton	43 min
Aug 17, 5:17 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	58 min
Aug 17, 7:56 PM EDT	Severe Thunderstorm Warning	PHI	Montgomery	19 min

Nearby

Tornado Warnings in Pennsylvania, 2007 Every tornado warning in 2007 Tornadoes in 2007

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.