Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 97, NWS Philadelphia/Mount Holly

July 8, 2014Berks County, Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 8, 2014, 7:08 PM EDT for Berks County, Chester County, Pennsylvania. It was in force for 82 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: Jul 8, 2014, 7:08 PM EDT (23:08 UTC)
Expired: Jul 8, 2014, 8:30 PM EDT
In force: 82 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Berks County, PA, Chester County, PA

The radar

The Philadelphia radar (KDIX), 124 km from the middle of the area, began a volume at 23:09 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 8, 7:42 PM EDT	TSTM WND DMG	Wernersville, PA	TREE REPORTED DOWN IN WERNERSVILLE.
Jul 8, 7:50 PM EDT	TSTM WND DMG	Wyomissing, PA	SEVERAL LARGE TREE LIMBS DOWN.
Jul 8, 8:00 PM EDT	TSTM WND GST 48	West Grove, PA
Jul 8, 8:05 PM EDT	TSTM WND DMG	Coatesville, PA	MULTIPLE TREES AND WIRES DOWN THROUGHOUT THE COUNTY. APPROXIMATELY 50000 CUSTOMERS WITHOUT POWER.
Jul 8, 8:13 PM EDT	TSTM WND DMG	Exton, PA	LARGE TREE LIMBS REPORTED 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
Jul 8, 5:05 PM EDT	Severe Thunderstorm Watch	SPC	5 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.1 hours before the alert went out and 83 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: 132 J/kg
Mixed-layer CIN: -176 J/kg
Mixed-layer LCL: 1646 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 77 m²/s²
0-3 km storm-relative helicity: 123 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.

980 
WUUS51 KPHI 082308
SVRPHI
PAC011-029-090030-
/O.NEW.KPHI.SV.W.0097.140708T2308Z-140709T0030Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
708 PM EDT TUE JUL 8 2014

...THIS IS AN EXTREMELY DANGEROUS AND POTENTIALLY LIFE THREATENING
SITUATION...

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 830 PM EDT

* AT 706 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM. THE STORM WAS NEAR TOWER CITY...MOVING
  NORTHEAST AT 35 MPH. THIS STORM IS CAPABLE OF PRODUCING DESTRUCTIVE
  WINDS IN EXCESS OF 70 MPH...AND LARGE HAIL. 

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  WOMELSDORF AND PARKESBURG AROUND 725 PM EDT...
  STRAUSSTOWN AND BERNVILLE AROUND 730 PM EDT...
  SINKING SPRING AND COATESVILLE AROUND 735 PM EDT...
  LEESPORT AND FAIRVIEW HGTS AROUND 740 PM EDT...
  HAMBURG AND SHOEMAKERSVILLE AROUND 745 PM EDT...
  PUGHTOWN AND LIONVILLE AROUND 750 PM EDT...

* OTHER SEVERE THUNDERSTORMS WERE LOCATED IN YORK COUNTY MOVING EAST 
  AT AROUND 35 MPH. THESE SEVERE THUNDERSTORMS WILL MOVE INTO        
  WESTERN CHESTER COUNTY BETWEEN 730 PM AND 800 PM.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE ARE DANGEROUS STORMS. IF YOU ARE IN THEIR PATH...MOVE 
INDOORS TO A STURDY BUILDING AND STAY AWAY FROM WINDOWS. WHEN IT IS 
SAFE TO DO SO...REPORT SEVERE WEATHER TO LOCAL LAW ENFORCEMENT OR TO 
THE NATIONAL WEATHER SERVICE.

THESE SEVERE THUNDERSTORMS HAVE A HISTORY OF PRODUCING WIND DAMAGE IN
CENTRAL PENNSYLVANIA. DO NOT STAY OUTDOORS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM EDT
TUESDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY
AND EASTERN PENNSYLVANIA. A SEVERE THUNDERSTORM WATCH ALSO REMAINS IN
EFFECT UNTIL MIDNIGHT EDT WEDNESDAY MORNING FOR NORTHEAST NEW JERSEY.

&&

LAT...LON 4058 7603 4065 7599 4068 7589 4045 7553
      4024 7570 4024 7560 4012 7546 4009 7546
      4007 7536 3988 7560 3984 7558 3980 7571
      3972 7578 3972 7613 3988 7599 4011 7595
      4014 7589 4050 7644 4050 7643
TIME...MOT...LOC 2304Z 246DEG 36KT 4062 7661

$$

FORECASTER:
JJM

1 follow-up statement

917 
WWUS51 KPHI 082340
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
740 PM EDT TUE JUL 8 2014

PAC011-029-090030-
/O.CON.KPHI.SV.W.0097.000000T0000Z-140709T0030Z/
BERKS PA-CHESTER PA-
740 PM EDT TUE JUL 8 2014

...THIS IS AN EXTREMELY DANGEROUS AND POTENTIALLY LIFE THREATENING
SITUATION...

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR CHESTER AND BERKS COUNTIES...

AT 734 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DESTRUCTIVE WINDS 
IN EXCESS OF 70 MPH. THESE THUNDERSTORMS WERE LOCATED ALONG A LINE 
EXTENDING FROM FREDERICKSBURG SOUTH TO THE PENNSYLVANIA MARYLAND 
BORDER. THIS LINE IS JUST NOW ENTERING WESTERN BERKS COUNTY...AND 
WILL ENTER WESTERN CHESTER COUNTY BY ABOUT 745 PM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS AN UNUSUALLY DANGEROUS SITUATION. SEEK SHELTER NOW INSIDE A 
STURDY STRUCTURE AND STAY AWAY FROM WINDOWS! SEVERE WIND AND LARGE 
HAIL ARE THE PRIMARY THREATS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM EDT
TUESDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY
AND EASTERN PENNSYLVANIA. A SEVERE THUNDERSTORM WATCH ALSO REMAINS IN
EFFECT UNTIL MIDNIGHT EDT WEDNESDAY MORNING FOR NORTHEAST NEW JERSEY.

&&

LAT...LON 4058 7603 4065 7599 4068 7589 4045 7553
      4024 7570 4024 7560 4012 7546 4009 7546
      4007 7536 3988 7560 3984 7558 3980 7571
      3972 7578 3972 7613 3988 7599 4011 7595
      4014 7589 4050 7644 4050 7643
TIME...MOT...LOC 2336Z 238DEG 47KT 4043 7623

$$

JJM

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 7, 9:42 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	63 min
Jul 7, 10:04 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	3 hr
Jul 7, 10:45 PM EDT	Special Weather Statement	PHI	Northampton	60 min
Jul 8, 3:51 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	24 min
Jul 8, 4:12 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	33 min
Jul 8, 7:19 PM EDT	Severe Thunderstorm Warning	PHI	Carbon	116 min
Jul 8, 7:48 PM EDT	Severe Thunderstorm Warning	PHI	Monroe	106 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2014 Every severe thunderstorm warning in 2014

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.