Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 154, NWS Philadelphia/Mount Holly

June 29, 2019Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 29, 2019, 3:09 PM EDT for Chester County, Pennsylvania. It was in force for 51 min. 19 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 29, 2019, 3:09 PM EDT (19:09 UTC)
Expired
Jun 29, 2019, 4:00 PM EDT
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Chester County, PA

The radar

The Philadelphia radar (KDIX), 123 km from the middle of the area, began a volume at 19:08 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

TimeReportWhereRemark
Jun 29, 3:24 PM EDTTSTM WND DMG2 Ne West Sadsbury Twp, PADOWNED TREE BLOCKING THE ROADWAY AT THE INTERSECTION OF SANDY HILL ROAD AND TYLER DRIVE. TIME ESTIMATED FROM RADAR.
Jun 29, 3:26 PM EDTTSTM WND DMG1 Nnw Sadsburyville, PADOWNED TREE NEAR THE INTERSECTION OF AIRPORT ROAD AND ASH ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:26 PM EDTTSTM WND DMG1 Sw West Brandywine Tw, PADOWNED TREE ON CEDAR KNOLL ROAD IN WEST CALN TWP. TIME ESTIMATED FROM RADAR.
Jun 29, 3:26 PM EDTTSTM WND DMG2 W West Caln Twp, PADOWNED TREE BLOCKING THE ROADWAY AT THE INTERSECTION OF KINGS HIGHWAY AND ASH ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:29 PM EDTTSTM WND DMG1 Sse Parkesburg, PADOWNED TREE NEAR THE INTERSECTION OF LIMESTONE ROAD AND OLD RACETRACK ROAD. TIME ESTIMATED FROM RADAR..
Jun 29, 3:31 PM EDTTSTM WND DMG1 Sse Atglen, PADOWNED TREES AND POWER LINES ON AND NEAR FALLOWFIELD ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:31 PM EDTHAIL 1Wagontown, PA
Jun 29, 3:33 PM EDTTSTM WND DMG1 S West Brandywine Twp, PADOWNED TREE BLOCKING MONACY ROAD NEAR MANOR ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:33 PM EDTHAIL 1Coatesville, PATIME ESTIMATED FROM RADAR.
Jun 29, 3:37 PM EDTTSTM WND DMG1 Se Atglen, PADOWNED TREE ON GAP NEWPORT PIKE NEAR GLEN RUN ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:41 PM EDTTSTM WND DMG2 S Parkesburg, PADOWNED TREE BLOCKING LIMESTONE ROAD NEAR HIGHLAND ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:47 PM EDTTSTM WND DMGEast Fallowfield Twp, PADOWNED TREE NEAR THE INTERSECTION OF STRASBURG ROAD AND YOUNGSBURG ROAD. TIME ESTIMATED FROM RADAR.
Jun 29, 3:51 PM EDTTSTM WND DMG1 Nnw East Caln Twp, PADOWNED TREE NEAR THE INTERSECTION OF WILLIAM SALESBURY DRIVE AND HICKORY DRIVE. TIME ESTIMATED FROM RADAR.
Jun 29, 3:51 PM EDTTSTM WND DMGCoatesville, PACORRECTS PREVIOUS TSTM WND DMG REPORT FROM COATESVILLE. PHOTO OF A LARGE TREE DOWN. TIME ESTIMATED FROM RADAR.
Jun 29, 3:52 PM EDTHAIL 0.252 N Coatesville, PA
Jun 29, 3:54 PM EDTTSTM WND DMG3 Nnw East Caln Twp, PADOWNED TREE BLOCKING DORIAN MILL ROAD NEAR ROBERT DEAN DRIVE. TIME ESTIMATED FROM RADAR.
Jun 29, 3:58 PM EDTTSTM WND DMG1 Nnw East Caln Twp, PADOWNED TREE NEAR THE INTERSECTION OF WOODLAND DRIVE AND SANTILLO WAY. TIME ESTIMATED FROM RADAR.
Jun 29, 4:05 PM EDTTSTM WND DMGLandenberg, PATREES DOWN. TIME ESTIMATED FROM RADAR.
Jun 29, 4:08 PM EDTTSTM WND DMG1 Ssw Kennett Square, PADOWNED TREE NEAR THE INTERSECTION OF ORIOLE DRIVE AND CHANDLER MILL ROAD. TIME ESTIMATED FROM RADAR.

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.

IssuedProductOfficeLasted
Jun 29, 12:08 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.2 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 2019-06-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 927 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 2019-06-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -10 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
927 J/kg
Mixed-layer CIN
-115 J/kg
Mixed-layer LCL
1390 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
-10 m²/s²
0-3 km storm-relative helicity
2 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

797 
WUUS51 KPHI 291909 RRA
SVRPHI
PAC029-292000-
/O.NEW.KPHI.SV.W.0154.190629T1909Z-190629T2000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
309 PM EDT Sat Jun 29 2019

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Chester County in southeastern Pennsylvania...

* Until 400 PM EDT.

* At 309 PM EDT, severe thunderstorms were located along a line
  extending from near Honey Brook to near Cochranville, moving east
  at 30 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Coatesville, Downingtown, Kennett Square, Parkesburg, West Grove,
  Honey Brook, Cochranville, Marshallton, Ladenberg,
  Lionville-Marchwood, Atglen, South Coatesville, Avondale, Modena,
  Thorndale and Toughkenamon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with these storms. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4004 7593 4011 7594 4007 7565 3986 7567
      3977 7576 3981 7592 3997 7599
TIME...MOT...LOC 1909Z 279DEG 25KT 4005 7595 3987 7587 

HAIL...0.75IN
WIND...60MPH
 
$$

CMS
1 follow-up statement
256 
WWUS51 KPHI 291930
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
330 PM EDT Sat Jun 29 2019

PAC029-292000-
/O.CON.KPHI.SV.W.0154.000000T0000Z-190629T2000Z/
Chester PA-
330 PM EDT Sat Jun 29 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT
FOR CENTRAL CHESTER COUNTY...

At 330 PM EDT, a severe thunderstorm was located over Coatesville, or
13 miles southeast of New Holland, moving southeast at 15 mph.

HAZARD...60 mph wind gusts and half dollar size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Coatesville, Downingtown, Parkesburg, Honey Brook, Marshallton,
Lionville-Marchwood, South Coatesville, Modena and Thorndale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Continuous cloud to ground lightning is occurring with this storm.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4004 7593 4011 7594 4007 7565 3986 7567
      3993 7587 3997 7599
TIME...MOT...LOC 1930Z 323DEG 15KT 3999 7587 

HAIL...1.25IN
WIND...60MPH
 
$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 29, 2:27 PM EDTSevere Thunderstorm WarningPHIBerks63 min
Jun 29, 2:46 PM EDTSpecial Weather StatementPHIChester29 min
Jun 29, 3:06 PM EDTSpecial Weather StatementPHIChester24 min
Jun 29, 3:20 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery, Northampton55 min
Jun 29, 3:24 PM EDTSevere Thunderstorm WarningPHIDelaware36 min
Jun 29, 3:27 PM EDTSevere Thunderstorm WarningPHIChester53 min
Jun 29, 3:45 PM EDTFlash Flood WarningPHIChester3 hr
Jun 29, 3:52 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia53 min
Jun 29, 3:56 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery49 min
Jun 29, 3:59 PM EDTSevere Thunderstorm WarningPHIChester, Delaware46 min
Jun 29, 4:00 PM EDTFlash Flood WarningPHIChester, Delaware3 hr
Jun 29, 4:17 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh, Northampton3 hr
Jun 29, 4:28 PM EDTSevere Thunderstorm WarningPHIBucks, Delaware, Montgomery, Philadelphia47 min
Jun 29, 4:41 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia3 hr
Jun 29, 7:10 PM EDTSpecial Weather StatementPHIBerks35 min
Jun 29, 7:16 PM EDTSpecial Weather StatementPHILebanon29 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2019Every severe thunderstorm warning in 2019

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.