Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2013

Severe Thunderstorm Warning 89, NWS Philadelphia/Mount Holly

August 13, 20135 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 13, 2013, 6:07 AM EDT for 5 counties in Pennsylvania. It was in force for 53 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 13, 2013, 6:07 AM EDT (10:07 UTC)
Expired: Aug 13, 2013, 7:00 AM EDT
In force: 53 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 73 km from the middle of the area, began a volume at 10:10 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
Aug 13, 6:16 AM EDT	TSTM WND DMG	Schuylkill Twp, PA	DOWNED TREES AND WIRES.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 10.1 hours before the alert went out and 220 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: 1 J/kg
Mixed-layer CIN: -66 J/kg
Mixed-layer LCL: 1841 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

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

917 
WUUS51 KPHI 131007
SVRPHI
PAC017-029-045-091-101-131100-
/O.NEW.KPHI.SV.W.0089.130813T1007Z-130813T1100Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
607 AM EDT TUE AUG 13 2013

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CENTRAL BUCKS COUNTY IN SOUTHEAST PENNSYLVANIA...
  SOUTHERN MONTGOMERY COUNTY IN SOUTHEAST PENNSYLVANIA...
  PHILADELPHIA COUNTY IN SOUTHEAST PENNSYLVANIA...
  NORTHERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  EAST CENTRAL CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 700 AM EDT

* AT 604 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM. THE STORM WAS NEAR WEST GOSHEN...MOVING
  NORTHEAST AT 30 MPH. THIS STORM IS CAPABLE OF PRODUCING DAMAGING
  WINDS IN EXCESS OF 60 MPH. 

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PHOENIXVILLE AROUND 615 AM EDT...
  NEWTOWN SQUARE AND BROOMALL AROUND 620 AM EDT...
  RADNOR TOWNSHIP AND TROUT LAKE AROUND 625 AM EDT...
  BRYN MAWR AND NORRISTOWN AROUND 630 AM EDT...
  CONSHOHOCKEN AND NARBERTH AROUND 635 AM EDT...
  CHESTNUT HILL AND PLYMOUTH MEETING AROUND 640 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4007 7570 4032 7511 4004 7498 4002 7501
      4002 7503 3998 7508 3997 7510 3989 7560
TIME...MOT...LOC 1007Z 247DEG 24KT 4000 7552

$$

KLINE

1 follow-up statement

753 
WWUS51 KPHI 131028
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
628 AM EDT TUE AUG 13 2013

PAC017-029-045-091-101-131100-
/O.CON.KPHI.SV.W.0089.000000T0000Z-130813T1100Z/
BUCKS PA-MONTGOMERY PA-PHILADELPHIA PA-DELAWARE PA-CHESTER PA-
628 AM EDT TUE AUG 13 2013

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 700 AM EDT
FOR EAST CENTRAL CHESTER...NORTHERN DELAWARE...PHILADELPHIA...
SOUTHERN MONTGOMERY AND CENTRAL BUCKS COUNTIES...

AT 624 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR RADNOR TOWNSHIP...OR 13
MILES NORTHEAST OF WEST CHESTER...MOVING NORTHEAST AT 30 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
CONSHOHOCKEN AND NORRISTOWN AROUND 635 AM EDT...
PLYMOUTH MEETING AND BLUE BELL AROUND 640 AM EDT...
FLOURTOWN AND WYNDMOOR AROUND 645 AM EDT...
ORELAND AND GLENSIDE AROUND 650 AM EDT...
ABINGTON AND WILLOW GROVE AROUND 655 AM EDT...
BRYN ATHYN AND HATBORO AROUND 700 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 4032 7511 4004 7498 3997 7510 3991 7547
      4013 7557
TIME...MOT...LOC 1027Z 247DEG 24KT 4005 7536

$$

KLINE

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 13, 2:45 AM EDT	Flash Flood Watch	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	9 hr
Aug 13, 5:15 AM EDT	Areal Flood Advisory	PHI	Berks, Chester, Montgomery	4 hr
Aug 13, 5:47 AM EDT	Flash Flood Warning	PHI	Chester	4 hr
Aug 13, 6:07 AM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	7 hr
Aug 13, 6:20 AM EDT	Areal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	4 hr
Aug 13, 6:23 AM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	67 min
Aug 13, 6:32 AM EDT	Tornado Warning	PHI	Chester	43 min
Aug 13, 6:36 AM EDT	Flash Flood Warning	PHI	Chester, Delaware, Montgomery	8 hr
Aug 13, 7:05 AM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	40 min
Aug 13, 7:14 AM EDT	Flash Flood Warning	PHI	Berks	4 hr
Aug 13, 7:42 AM EDT	Special Weather Statement	PHI	Philadelphia	48 min
Aug 13, 7:54 AM EDT	Flash Flood Warning	PHI	Delaware, Montgomery, Philadelphia	8 hr
Aug 13, 7:54 AM EDT	Special Weather Statement	PHI	Delaware, Philadelphia	66 min
Aug 13, 8:07 AM EDT	River Flood Warning	PHI	Chester	9 hr
Aug 13, 8:20 AM EDT	Flash Flood Warning	PHI	Bucks	8 hr
Aug 13, 9:50 AM EDT	Flash Flood Warning	PHI	Chester	4 hr
Aug 13, 11:22 AM EDT	River Flood Warning	PHI	Chester, Delaware	16 hr
Aug 13, 2:18 PM EDT	Areal Flood Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	9 hr

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.