Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 75, NWS Philadelphia/Mount Holly

June 24, 2010Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 24, 2010, 2:31 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 59 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: Jun 24, 2010, 2:31 PM EDT (18:31 UTC)
Expired: Jun 24, 2010, 3:30 PM EDT
In force: 59 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 124 km from the middle of the area, began a volume at 18:33 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 24, 2:45 PM EDT	TSTM WND DMG	Phoenixville, PA	LARGE TREE LIMBS DOWN ACROSS THE AREA.
Jun 24, 2:50 PM EDT	TSTM WND DMG	Ese Glen Echo, PA	EXTENSIVE TREE DAMAGE IN GLENMOORE. WIDESPEAD TREE DOWN THROUGHOUT THE COUNTY WITH SEVERAL ON HOUSES AND CARS.
Jun 24, 3:00 PM EDT	TSTM WND DMG	Exton, PA	TREES AND WIRES DOWN IN EXTON

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 24, 12:28 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.5 hours before the alert went out and 63 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: 126 J/kg
Mixed-layer CIN: -170 J/kg
Mixed-layer LCL: 1592 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 133 m²/s²
0-3 km storm-relative helicity: 65 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.

567 
WUUS51 KPHI 241831
SVRPHI
PAC029-091-241930-
/O.NEW.KPHI.SV.W.0075.100624T1831Z-100624T1930Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
231 PM EDT THU JUN 24 2010

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  WEST CENTRAL MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 330 PM EDT

* AT 229 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 14
  MILES NORTHWEST OF HONEY BROOK...OR 12 MILES SOUTHWEST OF
  READING...AND MOVING SOUTHEAST AT 40 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ELVERSON AND HONEY BROOK AROUND 250 PM EDT...
  GLENMOORE AROUND 300 PM EDT...
  6 MILES SOUTHWEST OF PUGHTOWN AROUND 305 PM EDT...
  LIONVILLE...CHESTER SPRINGS AND DOWNINGTOWN AROUND 310 PM EDT...
  WEST CHESTER AROUND 315 PM EDT...
  6 MILES SOUTHWEST OF VALLEY FORGE AROUND 320 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS!

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 600 PM EDT
THURSDAY EVENING FOR NORTHEAST PENNSYLVANIA. A SEVERE THUNDERSTORM
WATCH ALSO REMAINS IN EFFECT UNTIL 800 PM EDT THURSDAY EVENING FOR
DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND SOUTHEASTERN
PENNSYLVANIA.

&&

LAT...LON 3987 7601 3991 7601 3993 7600 3996 7600
      4003 7595 4011 7595 4024 7571 4031 7565
      4024 7532 3976 7578 3984 7603
TIME...MOT...LOC 1830Z 294DEG 34KT 4022 7610

$$

KRUZDLO

1 follow-up statement

881 
WWUS51 KPHI 241846
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
246 PM EDT THU JUN 24 2010

PAC029-091-241930-
/O.CON.KPHI.SV.W.0075.000000T0000Z-100624T1930Z/
CHESTER PA-MONTGOMERY PA-
246 PM EDT THU JUN 24 2010

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR WEST CENTRAL MONTGOMERY AND CHESTER COUNTIES...

AT 241 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DESTRUCTIVE WINDS IN EXCESS OF 70 MPH.  THIS STORM WAS
LOCATED NEAR HONEY BROOK...OR 12 MILES SOUTH OF READING...MOVING
SOUTHEAST AT 40 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  ELVERSON BY 250 PM EDT...
  GLENMOORE BY 255 PM EDT...
  LIONVILLE...DOWNINGTOWN...THORNDALE AND CHESTER SPRINGS BY 305 PM
  EDT...
  EXTON AND 6 MILES NORTHEAST OF MARSHALLTON BY 310 PM EDT...
  WEST CHESTER BY 315 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS STORM HAS A HISTORY OF PRODUCING WIDESPREAD WIND DAMAGE ACROSS 
LEBANON AND LANCASTER COUNTIES. THIS IS AN EXTREMELY DANGEROUS 
SITUATION. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY AWAY 
FROM WINDOWS!

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 600 PM EDT
THURSDAY EVENING FOR NORTHEAST PENNSYLVANIA. A SEVERE THUNDERSTORM
WATCH ALSO REMAINS IN EFFECT UNTIL 800 PM EDT THURSDAY EVENING FOR
DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND SOUTHEASTERN
PENNSYLVANIA.

&&

LAT...LON 3987 7601 3991 7601 3993 7600 3996 7600
      4003 7595 4011 7595 4024 7571 4031 7565
      4024 7532 3976 7578 3984 7603
TIME...MOT...LOC 1844Z 299DEG 36KT 4015 7592

$$

KRUZDLO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 24, 12:36 PM EDT	Special Weather Statement	PHI	Monroe	54 min
Jun 24, 1:16 PM EDT	Special Weather Statement	PHI	Monroe	59 min
Jun 24, 1:59 PM EDT	Severe Thunderstorm Warning	PHI	Berks	66 min
Jun 24, 2:56 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	64 min
Jun 24, 3:13 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	62 min
Jun 24, 3:29 PM EDT	Severe Thunderstorm Warning	PHI	Chester	61 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2010 Every severe thunderstorm warning in 2010

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.