Alert archive / Pennsylvania / Tornado Warnings in 2020
Tornado Warning 12, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this tornado warning at Aug 4, 2020, 7:23 AM EDT for 4 counties in Pennsylvania. It was in force for 20 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
- Aug 4, 2020, 7:23 AM EDT (11:23 UTC)
- Expired
- Aug 4, 2020, 7:43 AM EDT
- In force
- 20 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.0 in
Counties Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 75 km from the middle of the area, began a volume at 11:26 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.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Aug 4, 7:23 AM EDT | Tornado Watch | SPC | 9 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 00:00Z, 11.4 hours before the alert went out and 213 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.
- Mixed-layer CAPE
- 89 J/kg
- Mixed-layer CIN
- -54 J/kg
- Mixed-layer LCL
- 889 m above ground
- 0-6 km bulk shear
- 43 kt
- 0-1 km storm-relative helicity
- 65 m²/s²
- 0-3 km storm-relative helicity
- 140 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
445
WFUS51 KPHI 041123
TORPHI
PAC029-045-091-101-041200-
/O.NEW.KPHI.TO.W.0012.200804T1123Z-200804T1200Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
723 AM EDT Tue Aug 4 2020
The National Weather Service in Mount Holly NJ has issued a
* Tornado Warning for...
Southeastern Montgomery County in southeastern Pennsylvania...
Northeastern Chester County in southeastern Pennsylvania...
Western Philadelphia County in southeastern Pennsylvania...
Northeastern Delaware County in southeastern Pennsylvania...
* Until 800 AM EDT.
* At 722 AM EDT, a severe thunderstorm capable of producing a tornado
was located over Philadelphia International Airport, or near
Gloucester City, moving north at 25 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, Yeadon, Conshohocken, Folcroft, Paulsboro, Narberth,
National Park, East Lansdowne, Darby Township, Morris Park,
Germantown, Bryn Mawr, Trout Lake, South Philadelphia, Radnor
Township, Broomall, Roxborough, Chestnut Hill, Philadelphia
International Airport and Drexel Hill.
This includes the following highways...
Interstate 95 in Pennsylvania between mile markers 10 and 15.
Interstate 76 in Pennsylvania between mile markers 328 and 349.
Interstate 676 in Pennsylvania near mile marker 0.
Interstate 476 in Pennsylvania between mile markers 6 and 18.
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.
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 4007 7546 4012 7515 3988 7518 3986 7524
3985 7525 3985 7527
TIME...MOT...LOC 1122Z 171DEG 23KT 3987 7524
TORNADO...RADAR INDICATED
HAIL...0.00IN
$$
Gorse3 follow-up statements
378
WWUS51 KPHI 041129
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
729 AM EDT Tue Aug 4 2020
PAC029-041139-
/O.CAN.KPHI.TO.W.0012.000000T0000Z-200804T1200Z/
Chester PA-
729 AM EDT Tue Aug 4 2020
...THE TORNADO WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...
The tornadic thunderstorm which prompted the warning is expected to
stay east of this area. Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 400 PM EDT for southeastern
Pennsylvania.
LAT...LON 4007 7536 4006 7539 4008 7540 4012 7515
3989 7521 3988 7525 4004 7541
TIME...MOT...LOC 1129Z 173DEG 29KT 3992 7525
$$
PAC045-091-101-041200-
/O.CON.KPHI.TO.W.0012.000000T0000Z-200804T1200Z/
Montgomery PA-Philadelphia PA-Delaware PA-
729 AM EDT Tue Aug 4 2020
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 800 AM EDT FOR
SOUTHEASTERN MONTGOMERY...WESTERN PHILADELPHIA AND NORTHEASTERN
DELAWARE COUNTIES...
At 729 AM EDT, a severe thunderstorm capable of producing a tornado
was located over Yeadon, or 7 miles west of Gloucester City, moving
north at 35 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, Yeadon, Conshohocken, Narberth, East Lansdowne, Morris
Park, Germantown, Bryn Mawr, Trout Lake, South Philadelphia, Radnor
Township, Roxborough, Chestnut Hill, Drexel Hill, Darby Township,
Broomall, Plymouth Meeting, King Of Prussia, Darby and Lansdowne.
This includes the following highways...
Interstate 95 in Pennsylvania between mile markers 13 and 14.
Interstate 76 in Pennsylvania between mile markers 328 and 343, and
near mile marker 346.
Interstate 476 in Pennsylvania between mile markers 8 and 18.
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.
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 4007 7536 4006 7539 4008 7540 4012 7515
3989 7521 3988 7525 4004 7541
TIME...MOT...LOC 1129Z 173DEG 29KT 3992 7525
TORNADO...RADAR INDICATED
HAIL...0.00IN
$$
Gorse533
WWUS51 KPHI 041137
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
737 AM EDT Tue Aug 4 2020
PAC045-041146-
/O.CAN.KPHI.TO.W.0012.000000T0000Z-200804T1200Z/
Delaware PA-
737 AM EDT Tue Aug 4 2020
...THE TORNADO WARNING FOR NORTHEASTERN DELAWARE COUNTY IS
CANCELLED...
The tornadic thunderstorm which prompted the warning is moving east
of this area, therefore the warning has been cancelled.
A Tornado Watch remains in effect until 400 PM EDT for southeastern
Pennsylvania.
LAT...LON 4008 7531 4012 7515 3995 7520 3995 7524
TIME...MOT...LOC 1136Z 183DEG 29KT 3998 7523
$$
PAC091-101-041200-
/O.CON.KPHI.TO.W.0012.000000T0000Z-200804T1200Z/
Montgomery PA-Philadelphia PA-
737 AM EDT Tue Aug 4 2020
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 800 AM EDT FOR
SOUTHEASTERN MONTGOMERY AND NORTHWESTERN PHILADELPHIA COUNTIES...
At 736 AM EDT, a severe thunderstorm capable of producing a tornado
was located over Roxborough, or near Philadelphia, moving north at 35
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, Conshohocken, Narberth, Germantown, Roxborough,
Chestnut Hill, Plymouth Meeting, Flourtown, Wyndmoor, Oreland,
Glenside, Penn Wynne and Wyncote.
This includes Interstate 76 in Pennsylvania between mile markers 333
and 343.
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.
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 4008 7531 4012 7515 3995 7520 3995 7524
TIME...MOT...LOC 1136Z 183DEG 29KT 3998 7523
TORNADO...RADAR INDICATED
HAIL...0.00IN
$$
Gorse595
WWUS51 KPHI 041143
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
743 AM EDT Tue Aug 4 2020
PAC091-101-041153-
/O.CAN.KPHI.TO.W.0012.000000T0000Z-200804T1200Z/
Montgomery PA-Philadelphia PA-
743 AM EDT Tue Aug 4 2020
...THE TORNADO WARNING FOR SOUTHEASTERN MONTGOMERY AND NORTHWESTERN
PHILADELPHIA COUNTIES IS CANCELLED...
The storm which prompted the warning has weakened below severe
limits, and no longer appears capable of producing a tornado.
Therefore, the warning has been cancelled.
A Tornado Watch remains in effect until 400 PM EDT for southeastern
Pennsylvania.
LAT...LON 4008 7531 4012 7515 3995 7520 3995 7524
TIME...MOT...LOC 1142Z 171DEG 23KT 4003 7524
$$
GorseThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 4, 5:17 AM EDT | Areal Flood Advisory | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Aug 4, 7:28 AM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery | 3 hr |
| Aug 4, 8:11 AM EDT | Flash Flood Warning | PHI | Bucks, Lehigh, Montgomery, Northampton | 4 hr |
| Aug 4, 8:19 AM EDT | River Flood Warning | PHI | Delaware | 15 hr |
| Aug 4, 8:19 AM EDT | Tornado Warning | PHI | Bucks | 26 min |
| Aug 4, 9:23 AM EDT | Tornado Warning | PHI | Chester | 22 min |
| Aug 4, 9:29 AM EDT | Tornado Warning | PHI | Monroe, Northampton | 31 min |
| Aug 4, 9:38 AM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 4 hr |
| Aug 4, 9:58 AM EDT | Tornado Warning | PHI | Monroe | 16 min |
| Aug 4, 10:02 AM EDT | Flash Flood Warning | PHI | Chester, Delaware | 4 hr |
| Aug 4, 10:20 AM EDT | Flash Flood Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Aug 4, 10:51 AM EDT | Tornado Warning | PHI | Montgomery | 24 min |
| Aug 4, 11:01 AM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Aug 4, 11:13 AM EDT | Areal Flood Advisory | PHI | Berks, Carbon, Lehigh, Monroe, Northampton | 4 hr |
| Aug 4, 11:43 AM EDT | Flash Flood Warning | PHI | Berks, Lehigh, Northampton | 4 hr |
| Aug 4, 12:06 PM EDT | River Flood Warning | PHI | Chester | 11 hr |
| Aug 4, 12:37 PM EDT | River Flood Warning | PHI | Montgomery | 14 hr |
| Aug 4, 12:48 PM EDT | River Flood Warning | PHI | Chester, Delaware | 24 hr |
| Aug 4, 1:01 PM EDT | River Flood Warning | PHI | Bucks | 18 hr |
| Aug 4, 1:12 PM EDT | River Flood Warning | PHI | Berks | 10 hr |
| Aug 4, 1:12 PM EDT | River Flood Warning | PHI | Montgomery | 26 hr |
| Aug 4, 1:12 PM EDT | River Flood Warning | PHI | Chester, Montgomery, Philadelphia | 43 hr |
| Aug 4, 1:12 PM EDT | River Flood Warning | PHI | Montgomery, Philadelphia | 35 hr |
| Aug 4, 1:59 PM EDT | Areal Flood Warning | PHI | Chester, Delaware | 9 hr |
| Aug 4, 2:09 PM EDT | Areal Flood Warning | PHI | Berks, Chester, Delaware, Montgomery, Philadelphia | 15 hr |
| Aug 4, 2:23 PM EDT | River Flood Warning | PHI | Lehigh | 16 hr |
| Aug 4, 2:47 PM EDT | Areal Flood Warning | PHI | Bucks | 9 hr |
| Aug 4, 3:42 PM EDT | Areal Flood Warning | PHI | Lehigh, Northampton | 4 hr |
| Aug 4, 4:39 PM EDT | River Flood Warning | PHI | Monroe | 6 hr |
| Aug 4, 7:29 PM EDT | Areal Flood Warning | PHI | Lehigh, Northampton | 12 hr |
Nearby
Tornado Warnings in Pennsylvania, 2020Every tornado warning in 2020Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.