Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 110, NWS Philadelphia/Mount Holly

October 7, 2013Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Oct 7, 2013, 12:49 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 41 min. 2 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: Oct 7, 2013, 12:49 PM EDT (16:49 UTC)
Expired: Oct 7, 2013, 1:30 PM EDT
In force: 41 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Berks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 129 km from the middle of the area, began a volume at 16:51 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
Oct 7, 1:00 PM EDT	TSTM WND GST 57	Birdsboro, PA	A 57 MPH WIND GUST WAS MEASURED ON A HANDHELD ANEMOMETER DURING A LINE OF CONVECTION.
Oct 7, 1:08 PM EDT	TSTM WND DMG	Earl Twp, PA	TREES DOWN.

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
Oct 7, 8:56 AM EDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 4.8 hours before the alert went out and 55 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: 114 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 584 m above ground
0-6 km bulk shear: 48 kt
0-1 km storm-relative helicity: 149 m²/s²
0-3 km storm-relative helicity: 196 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.

983 
WUUS51 KPHI 071649
SVRPHI
PAC011-029-091-071730-
/O.NEW.KPHI.SV.W.0110.131007T1649Z-131007T1730Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1249 PM EDT MON OCT 7 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHEASTERN BERKS COUNTY IN EASTERN PENNSYLVANIA...
  NORTHWESTERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 130 PM EDT

* AT 1245 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS. THESE SEVERE STORMS EXTENDED FROM
  TERRE HILL TO WOODLAWN...MOVING NORTHEAST AT 40 MPH. THESE STORMS
  ARE CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH. 

* SEVERE THUNDERSTORMS WILL BE NEAR...
  PARKESBURG AND HONEY BROOK AROUND 1255 PM EDT...
  NEW MORGAN AROUND 100 PM EDT...
  BIRDSBORO AND WEST GROVE AROUND 105 PM EDT...
  GLENMOORE AROUND 110 PM EDT...
  KENNETT SQUARE AND DOWNINGTOWN AROUND 115 PM EDT...
  LIONVILLE AND PUGHTOWN AROUND 120 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY INSIDE A
STRONG BUILDING...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

DOPPLER RADAR HAS INDICATED SOME ROTATION WITHIN THIS STORM. WHILE
NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A TORNADO IS
SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM ON THE LOWEST
FLOOR.

&&

LAT...LON 3977 7607 3985 7603 3988 7599 3997 7600
      4004 7594 4011 7595 4014 7589 4024 7605
      4043 7551 3989 7558 3986 7560 3972 7599
      3972 7611 3975 7611
TIME...MOT...LOC 1649Z 244DEG 36KT 4017 7601 3967 7601

$$

SZATKOWSKI

1 follow-up statement

647 
WWUS51 KPHI 071724
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
124 PM EDT MON OCT 7 2013

PAC011-029-091-071730-
/O.CON.KPHI.SV.W.0110.000000T0000Z-131007T1730Z/
BERKS PA-MONTGOMERY PA-CHESTER PA-
124 PM EDT MON OCT 7 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 130 PM EDT
FOR CENTRAL CHESTER...NORTHWESTERN MONTGOMERY AND SOUTHEASTERN BERKS
COUNTIES...

AT 122 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS IN EXCESS OF 60 MPH. THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM BECHTELSVILLE TO WEST CHESTER...MOVING NORTHEAST AT 40
MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO WEST
GOSHEN...THORNDALE...STOWE...SOUTH POTTSTOWN...SOUTH COATESVILLE...
SANATOGA...POTTSGROVE...MODENA...KENILWORTH...HALFWAY HOUSE...EXTON
AND BOYERTOWN

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

DOPPLER RADAR HAS INDICATED SOME ROTATION WITHIN THIS STORM. WHILE
NOT IMMEDIATELY LIKELY...A TORNADO MAY DEVELOP. IF A TORNADO IS
SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

&&

LAT...LON 3986 7593 4002 7579 4035 7571 4043 7551
      3989 7558 3986 7560
TIME...MOT...LOC 1724Z 244DEG 36KT 4038 7556 3998 7560

$$

FORECASTER:  DRAG

The office that day

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

Issued	Product	Office	Counties	Lasted
Oct 7, 11:31 AM EDT	Special Weather Statement	PHI	Berks, Chester	59 min
Oct 7, 11:50 AM EDT	Severe Thunderstorm Warning	PHI	Berks	40 min
Oct 7, 12:12 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	63 min
Oct 7, 12:41 PM EDT	Special Weather Statement	PHI	Chester	64 min
Oct 7, 1:05 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	25 min
Oct 7, 1:30 PM EDT	Special Weather Statement	PHI	Monroe, Northampton	60 min
Oct 7, 1:33 PM EDT	Special Weather Statement	PHI	Bucks, Montgomery	42 min
Oct 7, 1:37 PM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	53 min
Oct 7, 1:59 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	46 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2013 Every severe thunderstorm warning in 2013

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.