Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 42, NWS Philadelphia/Mount Holly

June 2, 2009Chester County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 2, 2009, 3:15 PM EDT for Chester County, Pennsylvania; New Castle County, Delaware. It was in force for 38 min. 5 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: Jun 2, 2009, 3:15 PM EDT (19:15 UTC)
Expired: Jun 2, 2009, 3:53 PM EDT
In force: 38 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties New Castle County, DE, Chester County, PA

The radar

The Dover AFB radar (KDOX), 108 km from the middle of the area, began a volume at 19:15 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
Jun 2, 3:38 PM EDT	TSTM WND GST 76	Wilmington, DE	A 76 MPH THUNDERSTORM WIND GUST WAS MEASURED AT THE NEW CASTLE COUNTY AIRPORT IN WILMINGTON. THE WIND WAS SUSTAINED AT 52 MPH.
Jun 2, 3:38 PM EDT	TSTM WND GST 76	Wilmington Manor, DE	A 76 MPH THUNDERSTORM WIND GUST WAS MEASURED AT THE NEW CASTLE COUNTY AIRPORT IN WILMINGTON. THE WIND WAS SUSTAINED AT 52 MPH.
Jun 2, 3:40 PM EDT	TSTM WND DMG	2 Nne Wilmington Manor, DE	A ROOF COLLAPSED AT THE INDUSTRIAL AIRPORT PARK IN WILMINGTON.
Jun 2, 3:41 PM EDT	TSTM WND DMG	New Castle, DE	LARGE TREES DOWN.
Jun 2, 3:42 PM EDT	HAIL 0.75	Wilmington, DE	PENNY SIZE HAIL REPORTED ON ROUTES 131 AND 142.

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
Jun 2, 1:58 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.3 hours before the alert went out and 43 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1348 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 11 m²/s²
0-3 km storm-relative helicity: 63 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 021915
SVRPHI
DEC003-PAC029-022015-
/O.NEW.KPHI.SV.W.0042.090602T1915Z-090602T2015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
315 PM EDT TUE JUN 2 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITY OF WILMINGTON...
  SOUTH CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 415 PM EDT

* AT 315 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR WEST GROVE...OR 11 MILES
  NORTHWEST OF NEWARK...AND MOVING EAST AT 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  WEST GROVE AROUND 320 PM EDT...
  KEMBLESVILLE AROUND 325 PM EDT...
  LADENBERG AROUND 330 PM EDT...
  KENNETT SQUARE AROUND 335 PM EDT...
  HOCKESSIN AND NORTH STAR AROUND 340 PM EDT...
  ASHLAND AND PIKE CREEK AROUND 345 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT
TUESDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY AND SOUTHEAST PENNSYLVANIA.

&&

LAT...LON 3987 7587 3981 7546 3963 7560 3970 7580
      3973 7580 3972 7587 3974 7591
TIME...MOT...LOC 1915Z 289DEG 18KT 3981 7586

$$
JJM

1 follow-up statement

000 
WWUS51 KPHI 021953
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
353 PM EDT TUE JUN 2 2009

DEC003-PAC029-022001-
/O.CAN.KPHI.SV.W.0042.000000T0000Z-090602T2015Z/
CHESTER PA-NEW CASTLE DE-
353 PM EDT TUE JUN 2 2009

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN NEW CASTLE AND SOUTH
CENTRAL CHESTER COUNTIES IS CANCELLED...

THE STORM RESPONSIBLE FOR THE WARNING HAS MOVED OUT OF THE WARNED 
AREA.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 800 PM EDT
TUESDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY AND SOUTHEAST PENNSYLVANIA.

LAT...LON 3987 7587 3981 7546 3963 7560 3970 7580
      3973 7580 3972 7587 3974 7591
TIME...MOT...LOC 1951Z 289DEG 18KT 3975 7564

$$

KRUZDLO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 2, 2:53 PM EDT	Severe Thunderstorm Warning	PHI	Delaware	67 min
Jun 2, 4:39 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	51 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2009 Severe Thunderstorm Warnings in Delaware, 2009 Every severe thunderstorm warning in 2009

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.