Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2014

Severe Thunderstorm Warning 157, NWS Philadelphia/Mount Holly

September 6, 2014Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 6, 2014, 2:19 PM EDT for Chester County, Pennsylvania. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 6, 2014, 2:19 PM EDT (18:19 UTC)
Expired
Sep 6, 2014, 3:02 PM EDT
In force
43 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 126 km from the middle of the area, began a volume at 18:20 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 6, 2:07 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.3 hours before the alert went out and 174 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2014-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1444 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2014-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
1444 J/kg
Mixed-layer CIN
-42 J/kg
Mixed-layer LCL
867 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
18 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.

922 
WUUS51 KPHI 061819
SVRPHI
PAC029-061915-
/O.NEW.KPHI.SV.W.0157.140906T1819Z-140906T1915Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
219 PM EDT SAT SEP 6 2014

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  WESTERN CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...

* UNTIL 315 PM EDT

* AT 218 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM. THE STORM WAS NEAR ATGLEN...MOVING EAST AT 5
  MPH. THIS STORM IS CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH. 

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  HOMEVILLE AROUND 230 PM EDT...
  HONEY BROOK AROUND 235 PM EDT...
  PARKESBURG AROUND 250 PM EDT...
  COCHRANVILLE AROUND 255 PM EDT...
  COATESVILLE AND WEST GROVE AROUND 315 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE WINDS OF MORE THAN 57 MPH...OR HAIL ONE
INCH OR LARGER.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
SATURDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 3985 7603 3988 7599 3997 7600 4004 7594
      4010 7595 4023 7562 4022 7561 3973 7579
TIME...MOT...LOC 1819Z 281DEG 6KT 3993 7599

$$

FORECASTER: SFJ
2 follow-up statements
563 
WWUS51 KPHI 061833
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
233 PM EDT SAT SEP 6 2014

PAC029-061915-
/O.CON.KPHI.SV.W.0157.000000T0000Z-140906T1915Z/
CHESTER PA-
233 PM EDT SAT SEP 6 2014

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 315 PM EDT
FOR WESTERN CHESTER COUNTY...

AT 231 PM 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 ATGLEN...OR 14 MILES
SOUTHEAST OF NEW HOLLAND...MOVING EAST AT 5 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  PARKESBURG BY 240 PM EDT...
  COCHRANVILLE AND PARKESBURG BY 245 PM EDT...
  COCHRANVILLE BY 250 PM EDT...
  SOUTH COATESVILLE...MODENA...COATESVILLE AND 6 MILES NORTH OF WEST
  GROVE BY 315 PM EDT...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
SATURDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 3985 7603 3988 7599 3997 7600 4004 7594
      4010 7595 4023 7562 4022 7561 3973 7579
TIME...MOT...LOC 1833Z 281DEG 6KT 3992 7595

$$

SFJ
110 
WWUS51 KPHI 061902
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
302 PM EDT SAT SEP 6 2014

PAC029-061911-
/O.CAN.KPHI.SV.W.0157.000000T0000Z-140906T1915Z/
CHESTER PA-
302 PM EDT SAT SEP 6 2014

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN CHESTER COUNTY IS
CANCELLED...

THE STORM THAT PROMPTED THE WARNING HAS WEAKENED. HOWEVER...VERY 
HEAVY RAIN IS OCCURRING WITH THIS STORM. THUS...A FLOOD ADVISORY 
REMAINS IN EFFECT FOR MUCH OF CHESTER COUNTY.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT
SATURDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 3985 7603 3988 7599 3997 7600 4004 7594
      4010 7595 4023 7562 4022 7561 3973 7579
TIME...MOT...LOC 1901Z 281DEG 6KT 3991 7589

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 6, 1:37 PM EDTSpecial Weather StatementPHINorthampton53 min
Sep 6, 2:13 PM EDTSpecial Weather StatementPHIChester62 min
Sep 6, 2:43 PM EDTAreal Flood AdvisoryPHIChester4 hr
Sep 6, 3:21 PM EDTSpecial Weather StatementPHIBerks, Bucks, Lehigh, Montgomery54 min
Sep 6, 3:45 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery60 min
Sep 6, 3:51 PM EDTFlash Flood WarningPHIChester4 hr
Sep 6, 4:52 PM EDTSevere Thunderstorm WarningPHIDelaware36 min
Sep 6, 7:36 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton54 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2014Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.