Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 133, NWS Philadelphia/Mount Holly

July 6, 2020Chester County, Delaware County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 6, 2020, 5:20 PM EDT for Chester County, Delaware County, Pennsylvania. It was in force for 42 min. 3 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 6, 2020, 5:20 PM EDT (21:20 UTC)
Expired
Jul 6, 2020, 6:02 PM EDT
In force
42 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Chester County, PA, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 105 km from the middle of the area, began a volume at 21:19 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
Jul 6, 5:25 PM EDTTSTM WND GST 50Pocopson, PAWIRES DOWN NEAR THE INTERSECTION OF WEST STREET ROAD AND CREEK ROAD. TIME ESTIMATED FROM RADAR.
Jul 6, 5:27 PM EDTTSTM WND GST 581 Sw Birmingham Twp, PATREE AND WIRES DOWN NEAR THE INTERSECTION OF MEETINGHOUSE ROAD AND CREEK ROAD NORTH OF CHADDS FORD. TIME ESTIMATED FROM RADAR.
Jul 6, 5:32 PM EDTTSTM WND DMGPennsbury Twp, PAMULTIPLE REPORTS OF TREES DOWN INTO WIRES ON US-1. 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
Jul 6, 1:38 PM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.3 hours before the alert went out and 194 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 2020-07-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1250 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 2020-07-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 62 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
1250 J/kg
Mixed-layer CIN
-133 J/kg
Mixed-layer LCL
1150 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
62 m²/s²
0-3 km storm-relative helicity
57 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

046 
WUUS51 KPHI 062120
SVRPHI
PAC029-045-062215-
/O.NEW.KPHI.SV.W.0133.200706T2120Z-200706T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
520 PM EDT Mon Jul 6 2020

The National Weather Service in Mount Holly NJ has issued a

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

* Until 615 PM EDT.

* At 519 PM EDT, a severe thunderstorm was located over West Chester,
  moving southeast at 10 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...
  West Chester, Coatesville, Westtown, Downingtown, Honey Brook,
  Elverson, Cheyney, Pughtown, Elam, Marshallton, Lima, Trout Lake,
  Chelsea, Radnor Township, Lionville-Marchwood, Gradyville,
  Broomall, Glenmoore, Paoli and Chester Springs.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 300 and 324.
 Interstate 476 in Pennsylvania between mile markers 4 and 13.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 4014 7587 4021 7576 4004 7534 4002 7532
      4002 7531 4000 7530 3985 7541 3985 7562
      4003 7594 4004 7593 4011 7594
TIME...MOT...LOC 2119Z 311DEG 9KT 3995 7561 

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

BAH
2 follow-up statements
013 
WWUS51 KPHI 062151
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
551 PM EDT Mon Jul 6 2020

PAC029-045-062215-
/O.CON.KPHI.SV.W.0133.000000T0000Z-200706T2215Z/
Chester PA-Delaware PA-
551 PM EDT Mon Jul 6 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR CENTRAL CHESTER AND SOUTHWESTERN DELAWARE COUNTIES...

At 549 PM EDT, a severe thunderstorm was located over Concordville,
or near West Chester, moving southeast at 10 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...
West Chester, Westtown, Downingtown, Gradyville, Cheyney, Elam,
Marshallton, Lima, Concordville, Chelsea, Nether Providence Township,
Chester Township, West Goshen, Brookhaven, Media, Chester Heights,
South Coatesville, Springfield, Rose Valley and Modena.

This includes Interstate 476 in Pennsylvania between mile markers 4
and 5.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3985 7541 3985 7562 3996 7582 4002 7574
      3994 7534
TIME...MOT...LOC 2149Z 311DEG 9KT 3990 7554 

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

BAH
292 
WWUS51 KPHI 062202 RRA
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
602 PM EDT Mon Jul 6 2020

PAC029-045-062212-
/O.CAN.KPHI.SV.W.0133.000000T0000Z-200706T2215Z/
Chester PA-Delaware PA-
602 PM EDT Mon Jul 6 2020

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL CHESTER AND
SOUTHWESTERN DELAWARE COUNTIES IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 1100 PM EDT for
southeastern Pennsylvania.

LAT...LON 3985 7541 3985 7562 3996 7582 4002 7574
      3994 7534
TIME...MOT...LOC 2159Z 311DEG 9KT 3988 7551 

$$

BAH

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 6, 3:16 AM EDTHeat AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia12 hr
Jul 6, 12:34 PM EDTSpecial Weather StatementPHIPhiladelphia26 min
Jul 6, 12:45 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia60 min
Jul 6, 12:52 PM EDTFlash Flood WatchPHIBucks, Chester, Delaware, Montgomery, Philadelphia8 hr
Jul 6, 12:57 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia2 hr
Jul 6, 1:08 PM EDTFlash Flood WarningPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Jul 6, 1:15 PM EDTSevere Thunderstorm WarningPHIBucks60 min
Jul 6, 1:20 PM EDTSpecial Weather StatementPHIMontgomery25 min
Jul 6, 1:24 PM EDTSpecial Weather StatementPHIMonroe36 min
Jul 6, 1:43 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia62 min
Jul 6, 1:44 PM EDTSpecial Weather StatementPHIMontgomery31 min
Jul 6, 1:50 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery4 hr
Jul 6, 1:50 PM EDTSevere Thunderstorm WarningPHIMonroe40 min
Jul 6, 2:02 PM EDTAreal Flood AdvisoryPHIBucks118 min
Jul 6, 2:04 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery41 min
Jul 6, 2:10 PM EDTAreal Flood AdvisoryPHIMonroe2 hr
Jul 6, 2:18 PM EDTSpecial Weather StatementPHIMontgomery27 min
Jul 6, 2:27 PM EDTSevere Thunderstorm WarningPHIMontgomery48 min
Jul 6, 2:28 PM EDTSevere Thunderstorm WarningPHIMonroe28 min
Jul 6, 2:39 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Montgomery4 hr
Jul 6, 2:39 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia66 min
Jul 6, 2:41 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery49 min
Jul 6, 2:48 PM EDTAreal Flood AdvisoryPHIPhiladelphia4 hr
Jul 6, 2:51 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery24 min
Jul 6, 2:57 PM EDTFlash Flood Warning EmergencyCatastrophic damage threatPHIBucks, Delaware, Montgomery, Philadelphia4 hr
Jul 6, 3:00 PM EDTSevere Thunderstorm WarningPHIBucks, Northampton45 min
Jul 6, 3:11 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia49 min
Jul 6, 3:38 PM EDTSevere Thunderstorm WarningPHIBucks, Lehigh, Northampton52 min
Jul 6, 3:52 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia38 min
Jul 6, 3:56 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton64 min
Jul 6, 4:06 PM EDTSevere Thunderstorm WarningPHILehigh24 min
Jul 6, 4:07 PM EDTFlash Flood WarningPHIChester, Delaware, Montgomery4 hr
Jul 6, 4:31 PM EDTSevere Thunderstorm WarningPHIBerks, Lehigh, Monroe, Northampton44 min
Jul 6, 4:51 PM EDTAreal Flood AdvisoryPHICarbon, Monroe114 min
Jul 6, 5:00 PM EDTSevere Thunderstorm WarningPHIBerks, Carbon, Lehigh, Monroe, Northampton45 min
Jul 6, 5:01 PM EDTAreal Flood AdvisoryPHIBerks, Carbon, Lehigh, Monroe, Northampton119 min
Jul 6, 5:14 PM EDTSevere Thunderstorm WarningPHIChester61 min
Jul 6, 5:17 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton43 min
Jul 6, 5:29 PM EDTSevere Thunderstorm WarningPHIChester46 min
Jul 6, 5:43 PM EDTAreal Flood AdvisoryPHIChester, Delaware3 hr
Jul 6, 5:53 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery52 min
Jul 6, 6:13 PM EDTSevere Thunderstorm WarningPHIChester48 min
Jul 6, 6:14 PM EDTAreal Flood AdvisoryPHIBerks, Chester, Montgomery3 hr
Jul 6, 6:18 PM EDTSevere Thunderstorm WarningPHIBerks, Chester, Montgomery35 min
Jul 6, 6:54 PM EDTFlash Flood WarningPHIBerks, Chester, Montgomery109 min
Jul 6, 7:18 PM EDTSevere Thunderstorm WarningPHIMonroe36 min
Jul 6, 7:36 PM EDTSevere Thunderstorm WarningPHIChester69 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020Every severe thunderstorm warning in 2020

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.