Alert archive / Pennsylvania / Tornado Warnings in 2023

Tornado Warning 31, NWS Philadelphia/Mount Holly

August 7, 20234 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this tornado warning at Aug 7, 2023, 6:35 PM EDT for 4 counties in Pennsylvania. It was in force for 25 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
Aug 7, 2023, 6:35 PM EDT (22:35 UTC)
Expired
Aug 7, 2023, 7:00 PM EDT
In force
25 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Radar indicated
Hail
0.75 in

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

The radar

The Philadelphia radar (KDIX), 78 km from the middle of the area, began a volume at 22:36 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
Aug 7, 6:43 PM EDTTSTM WND DMGHaverford, PAReport of multiple trees down in Haverford on social media. Photo on social media of a tree down on a car. Time estimated via radar.
Aug 7, 6:46 PM EDTTSTM WND DMG1 Se King Of Prussia, PALarge tree down on I-76 Eastbound with a lane blockage. Time estimated from radar.
Aug 7, 6:49 PM EDTTSTM WND DMGChestnut Hill, PAPictures of extensive tree damage in Chestnut Hill. Time estimated from radar.
Aug 7, 6:50 PM EDTTSTM WND GST 55Glenside, PA
Aug 7, 7:00 PM EDTTSTM WND DMGHorsham Twp, PADavis Grove Road at Park Road closed due to downed tree. 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
Aug 7, 3:13 PM EDTTornado WatchSPC8 hr

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 10.6 hours before the alert went out and 221 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, Brookhaven, NY at 12:00Z on 2023-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 36 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, Brookhaven, NY at 12:00Z on 2023-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 143 square meters per square second.193958Sfc1 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
36 J/kg
Mixed-layer CIN
-8 J/kg
Mixed-layer LCL
726 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
143 m²/s²
0-3 km storm-relative helicity
167 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

863 
WFUS51 KPHI 072235
TORPHI
PAC029-045-091-101-072300-
/O.NEW.KPHI.TO.W.0031.230807T2235Z-230807T2300Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
635 PM EDT Mon Aug 7 2023

The National Weather Service in Mount Holly NJ has issued a

* Tornado Warning for...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Eastern Chester County in southeastern Pennsylvania...
  Northwestern Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 700 PM EDT.
    
* At 635 PM EDT, a severe thunderstorm capable of producing a tornado
  was located over Newtown Square, or 10 miles east of West Chester,
  moving northeast at 50 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Philadelphia, Norristown, Lansdale, West Norriton, East Norriton,
  Conshohocken, Hatboro, Ambler, Jenkintown, Abington, Bryn Athyn,
  Willow Grove, Bryn Mawr, Trout Lake, Radnor Township, Plymouth
  Meeting, Newtown Square, Chestnut Hill, King Of Prussia and
  Broomall.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 326 and 346.
 Northeast Extension between mile markers 21 and 27.
 Interstate 76 in Pennsylvania between mile markers 327 and 336.
 Interstate 476 in Pennsylvania between mile markers 9 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4029 7526 4015 7504 3994 7541 4000 7550
TIME...MOT...LOC 2235Z 220DEG 43KT 3999 7541 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

RCM
2 follow-up statements
733 
WWUS51 KPHI 072243
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
643 PM EDT Mon Aug 7 2023

PAC029-072253-
/O.CAN.KPHI.TO.W.0031.000000T0000Z-230807T2300Z/
Chester PA-
643 PM EDT Mon Aug 7 2023

...THE TORNADO WARNING FOR EASTERN CHESTER COUNTY IS CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled. A 
Severe Thunderstorm Warning remains in effect.

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

LAT...LON 4028 7526 4027 7522 4015 7504 4001 7536
      4004 7541 4007 7536 4006 7539 4009 7542
TIME...MOT...LOC 2243Z 220DEG 43KT 4007 7533 

$$

PAC045-091-101-072300-
/O.CON.KPHI.TO.W.0031.000000T0000Z-230807T2300Z/
Montgomery PA-Philadelphia PA-Delaware PA-
643 PM EDT Mon Aug 7 2023

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM EDT FOR
SOUTHEASTERN MONTGOMERY...NORTHWESTERN PHILADELPHIA AND NORTHERN
DELAWARE COUNTIES...
    
At 643 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Conshohocken, or 10 miles west of Philadelphia,
moving northeast at 50 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
Philadelphia, Norristown, Lansdale, West Norriton, East Norriton,
Conshohocken, Hatboro, Ambler, Abington, Bryn Athyn, Willow Grove,
Radnor Township, Plymouth Meeting, King Of Prussia, Chestnut Hill,
Bryn Mawr, Horsham, Bridgeport, North Wales and West Conshohocken.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 326 and 346.
 Northeast Extension between mile markers 21 and 26.
 Interstate 76 in Pennsylvania between mile markers 327 and 335.
 Interstate 476 in Pennsylvania between mile markers 12 and 19.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 4028 7526 4027 7522 4015 7504 4001 7536
      4004 7541 4007 7536 4006 7539 4009 7542
TIME...MOT...LOC 2243Z 220DEG 43KT 4007 7533 

TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN

$$

RCM
799 
WWUS51 KPHI 072250
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
650 PM EDT Mon Aug 7 2023

PAC045-091-101-072300-
/O.EXP.KPHI.TO.W.0031.000000T0000Z-230807T2300Z/
Montgomery PA-Philadelphia PA-Delaware PA-
650 PM EDT Mon Aug 7 2023

...THE TORNADO WARNING FOR SOUTHEASTERN MONTGOMERY...NORTHWESTERN
PHILADELPHIA AND NORTHERN DELAWARE COUNTIES WILL EXPIRE AT 700 PM
EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning will be allowed to expire.

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

Remember, a Severe Thunderstorm Warning still remains in effect.

LAT...LON 4028 7526 4027 7522 4015 7504 4001 7536
      4004 7541 4007 7536 4006 7539 4009 7542
TIME...MOT...LOC 2250Z 220DEG 43KT 4013 7527 

$$

RCM

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 5:33 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIBerks, Chester57 min
Aug 7, 5:37 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIDelaware53 min
Aug 7, 5:57 PM EDTAreal Flood AdvisoryPHIChester, Delaware79 min
Aug 7, 6:08 PM EDTTornado WarningPHIChester19 min
Aug 7, 6:21 PM EDTSevere Thunderstorm Warning Considerable damage threatPHIBerks, Bucks, Chester, Delaware, Montgomery, Philadelphia69 min
Aug 7, 6:29 PM EDTAreal Flood AdvisoryPHIChester, Delaware, Montgomery, Philadelphia63 min
Aug 7, 6:45 PM EDTSevere Thunderstorm WarningPHICarbon, Monroe45 min
Aug 7, 6:53 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Carbon, Lehigh, Monroe, Montgomery and 1 more52 min
Aug 7, 7:00 PM EDTAreal Flood AdvisoryPHIBerks, Lehigh, Montgomery, Northampton66 min
Aug 7, 7:20 PM EDTSevere Thunderstorm WarningPHIBucks58 min
Aug 7, 7:27 PM EDTSevere Thunderstorm WarningPHICarbon, Lehigh, Monroe, Northampton48 min

Nearby

Tornado Warnings in Pennsylvania, 2023Every tornado warning in 2023Tornadoes in 2023

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.