Alert archive / Pennsylvania / Tornado Warnings in 2021
Tornado Warning 36, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this tornado warning at Sep 1, 2021, 4:13 PM EDT for Chester County, Pennsylvania. It was in force for 32 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
- Sep 1, 2021, 4:13 PM EDT (20:13 UTC)
- Expired
- Sep 1, 2021, 4:45 PM EDT
- In force
- 32 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Tornado
- Radar indicated
- Hail
- 0.75 in
County Chester County, PA
The radar
The Dover AFB radar (KDOX), 122 km from the middle of the area, began a volume at 20:16 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
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 1, 4:15 PM EDT | TORNADO | 1 Sse Oxford, PA | AN EMBEDDED SUPERCELL IN A QUASI-LINEAR FEATURE PRODUCED A TORNADO NEAR OXFORD, PA. A PATH OF DAMAGE BEGAN IN CROP LAND NEAR THE INTERSECTION OF 5TH STREET AND WATERWAY ROAD. TREE DAMAGE CONTINUED NORTHEAST OF HERE. SIGNIFICANT DAMAGE OCCURRED IN THE WILTSHIRE |
| Sep 1, 4:17 PM EDT | TSTM WND DMG | 1 Se Oxford, PA | TREES AND POWER POLES SNAPPED AND ROOF DAMAGE ALONG SLATE HILL DRIVE IN EAST NOTTINGHAM TOWNSHIP. PROBABLE TORNADO. TIME ESTIMATED FROM RADAR. |
| Sep 1, 4:21 PM EDT | TSTM WND DMG | 2 S Upper Oxford Twp, PA | MULTIPLE TREES DOWN ALONG US 1 SOUTH NEAR NEW LONDON. POSSIBLE TORNADO. 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.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Sep 1, 12:40 PM EDT | Tornado Watch | SPC | 9 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 8.2 hours before the alert went out and 154 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
- 558 J/kg
- Mixed-layer CIN
- -21 J/kg
- Mixed-layer LCL
- 575 m above ground
- 0-6 km bulk shear
- 48 kt
- 0-1 km storm-relative helicity
- 122 m²/s²
- 0-3 km storm-relative helicity
- 223 m²/s²
- Significant tornado parameter
- 0.4
- Supercell composite
- 2.6
The text
As transmitted.
905
WFUS51 KPHI 012013
TORPHI
PAC029-012045-
/O.NEW.KPHI.TO.W.0036.210901T2013Z-210901T2045Z/
BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
413 PM EDT Wed Sep 1 2021
The National Weather Service in Mount Holly NJ has issued a
* Tornado Warning for...
Southwestern Chester County in southeastern Pennsylvania...
* Until 445 PM EDT.
* At 412 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Glen Roy, or 14 miles northwest of Elkton, moving
northeast 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...
Coatesville, Oxford, Parkesburg, Homeville, Glen Roy, Mount Vernon,
Cochranville, Atglen, South Coatesville and Modena.
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.
Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!
&&
LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
3981 7603 3983 7604 3987 7599 3992 7600
3994 7598 3995 7600 4001 7596 3996 7572
3972 7597 3972 7613
TIME...MOT...LOC 2012Z 204DEG 29KT 3975 7602
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Staarmann2 follow-up statements
870
WWUS51 KPHI 012023
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
423 PM EDT Wed Sep 1 2021
PAC029-012045-
/O.CON.KPHI.TO.W.0036.000000T0000Z-210901T2045Z/
Chester PA-
423 PM EDT Wed Sep 1 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 445 PM EDT FOR
SOUTHWESTERN CHESTER COUNTY...
At 423 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Homeville, or 15 miles northwest of Newark, moving
northeast at 35 mph.
HAZARD...Tornado.
SOURCE...Radar indicated rotation.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be damaged or destroyed. Damage
to roofs, windows, and vehicles will occur. Tree damage is
likely.
Locations impacted include...
Coatesville, Oxford, Parkesburg, Homeville, Mount Vernon,
Cochranville, Atglen, South Coatesville and Modena.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.
Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 3978 7590 3980 7603 3981 7603 3983 7604
3987 7599 3992 7600 3994 7598 3995 7600
4001 7596 3996 7572
TIME...MOT...LOC 2023Z 204DEG 29KT 3983 7597
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
Staarmann362
WWUS51 KPHI 012031
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
431 PM EDT Wed Sep 1 2021
PAC029-012045-
/O.CON.KPHI.TO.W.0036.000000T0000Z-210901T2045Z/
Chester PA-
431 PM EDT Wed Sep 1 2021
...A TORNADO WARNING REMAINS IN EFFECT UNTIL 445 PM EDT FOR WEST
CENTRAL CHESTER COUNTY...
At 431 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Cochranville, or 14 miles southeast of New Holland,
moving north at 40 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...
Coatesville, Parkesburg, Cochranville, Atglen, South Coatesville and
Modena.
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.
Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 3985 7588 3987 7599 3988 7599 3992 7600
3994 7598 3995 7600 4001 7596 3998 7580
TIME...MOT...LOC 2031Z 189DEG 36KT 3992 7594
TORNADO...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
$$
StaarmannThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 1, 6:19 AM EDT | Areal Flood Advisory | PHI | Chester, Delaware | 116 min |
| Sep 1, 6:49 AM EDT | Flash Flood Warning | PHI | Chester, Delaware, Philadelphia | 86 min |
| Sep 1, 11:24 AM EDT | Areal Flood Advisory | PHI | Berks, Carbon, Lehigh, Monroe, Northampton | 3 hr |
| Sep 1, 12:07 PM EDT | Flash Flood Warning | PHI | Carbon, Monroe | 4 hr |
| Sep 1, 1:29 PM EDT | Flash Flood Warning | PHI | Berks, Lehigh | 6 hr |
| Sep 1, 2:53 PM EDT | Flash Flood Warning | PHI | Berks, Chester, Delaware, Montgomery | 9 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Montgomery | 36 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Chester, Montgomery, Philadelphia | 43 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Montgomery, Philadelphia | 41 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Philadelphia | 39 hr |
| Sep 1, 3:55 PM EDT | River Flood Warning | PHI | Berks | 24 hr |
| Sep 1, 4:02 PM EDT | River Flood Warning | PHI | Monroe | 24 hr |
| Sep 1, 4:04 PM EDT | Areal Flood Warning | PHI | Carbon, Monroe, Northampton | 24 hr |
| Sep 1, 4:10 PM EDT | River Flood Warning | PHI | Monroe | 19 hr |
| Sep 1, 4:12 PM EDT | Flash Flood Warning | PHI | Berks, Bucks, Lehigh, Montgomery, Northampton | 7 hr |
| Sep 1, 4:12 PM EDT | River Flood Warning | PHI | Lehigh, Northampton | 25 hr |
| Sep 1, 4:12 PM EDT | River Flood Warning | PHI | Lehigh, Northampton | 24 hr |
| Sep 1, 4:12 PM EDT | River Flood Warning | PHI | Carbon | 15 hr |
| Sep 1, 4:20 PM EDT | River Flood Warning | PHI | Montgomery | 22 hr |
| Sep 1, 4:21 PM EDT | River Flood Warning | PHI | Bucks | 29 hr |
| Sep 1, 4:42 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery | 6 hr |
| Sep 1, 5:07 PM EDT | River Flood Warning | PHI | Chester | 17 hr |
| Sep 1, 5:13 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 47 min |
| Sep 1, 5:15 PM EDT | Tornado Warning | PHI | Delaware, Montgomery, Philadelphia | 30 min |
| Sep 1, 5:26 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 9 hr |
| Sep 1, 5:34 PM EDT | Tornado Warning | PHI | Bucks, Montgomery, Philadelphia | 26 min |
| Sep 1, 5:42 PM EDT | Flash Flood Warning | PHI | Bucks | 10 hr |
| Sep 1, 5:57 PM EDT | Tornado Warning | PHI | Bucks | 33 min |
| Sep 1, 6:08 PM EDT | Flash Flood Warning | PHI | Monroe, Northampton | 6 hr |
| Sep 1, 6:20 PM EDT | Tornado Warning | PHI | Bucks | 40 min |
| Sep 1, 6:22 PM EDT | Tornado Warning | PHI | Philadelphia | 23 min |
| Sep 1, 6:38 PM EDT | River Flood Warning | PHI | Chester, Delaware | 26 hr |
| Sep 1, 6:42 PM EDT | Tornado Warning | PHI | Bucks, Philadelphia | 33 min |
| Sep 1, 6:59 PM EDT | Severe Thunderstorm Warning | PHI | Bucks | 61 min |
| Sep 1, 7:04 PM EDT | Tornado Warning | PHI | Bucks | 26 min |
| Sep 1, 7:05 PM EDT | Flash Flood Warning | PHI | Bucks | 8 hr |
| Sep 1, 7:22 PM EDT | Tornado Warning | PHI | Bucks | 11 min |
| Sep 1, 7:23 PM EDT | Areal Flood Warning | PHI | Berks, Lehigh | 14 hr |
| Sep 1, 7:31 PM EDT | Flash Flood Warning | PHI | Bucks | 4 hr |
| Sep 1, 7:53 PM EDT | River Flood Warning | PHI | Delaware | 13 hr |
Nearby
Tornado Warnings in Pennsylvania, 2021Every tornado warning in 2021Tornadoes in 2021
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.