Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 249, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 11, 2021, 5:48 PM EDT for Berks County, Pennsylvania. It was in force for 57 min. 2 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 11, 2021, 5:48 PM EDT (21:48 UTC)
- Expired
- Aug 11, 2021, 6:45 PM EDT
- In force
- 57 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 1.0 in
- Wind
- 60.0 mph
County Berks County, PA
The radar
The Philadelphia radar (KDIX), 136 km from the middle of the area, began a volume at 21:49 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 |
|---|---|---|---|
| Aug 11, 6:08 PM EDT | TSTM WND DMG | West Wyomissing, PA | HALF OF LARGE MAPLE TREE DOWN ON ROAD. TIME ESTIMATED FROM RADAR. |
| Aug 11, 6:10 PM EDT | TSTM WND DMG | Spring Twp, PA | TREES DOWN ON WIRES ON JEFFERSON AVENUE IN SPRING TOWNSHIP.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 |
|---|---|---|---|
| Aug 11, 3:02 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 9.8 hours before the alert went out and 196 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
- 553 J/kg
- Mixed-layer CIN
- -190 J/kg
- Mixed-layer LCL
- 1301 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 20 m²/s²
- 0-3 km storm-relative helicity
- 77 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
911
WUUS51 KPHI 112148
SVRPHI
PAC011-112245-
/O.NEW.KPHI.SV.W.0249.210811T2148Z-210811T2245Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
548 PM EDT Wed Aug 11 2021
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
South central Berks County in eastern Pennsylvania...
* Until 645 PM EDT.
* At 548 PM EDT, a severe thunderstorm was located near Robesonia, or
8 miles north of Ephrata, moving east at 25 mph.
HAZARD...60 mph wind gusts and quarter 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...
Reading, Wyomissing, Birdsboro, Sinking Spring, Womelsdorf,
Wernersville, Robesonia, New Morgan, Spring Ridge, Shillington,
West Reading, Mount Penn, Mohnton, Kenhorst, St. Lawrence,
Wyomissing Hills, West Lawn, Lorane, Reiffton and Whitfield.
This includes the following highways...
Pennsylvania Turnpike between mile markers 296 and 299.
Interstate 176 in Pennsylvania between mile markers 1 and 11.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4036 7575 4014 7587 4031 7614 4036 7621
TIME...MOT...LOC 2148Z 274DEG 22KT 4030 7615
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
JEO3 follow-up statements
569
WWUS51 KPHI 112208
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
608 PM EDT Wed Aug 11 2021
PAC011-112245-
/O.CON.KPHI.SV.W.0249.000000T0000Z-210811T2245Z/
Berks PA-
608 PM EDT Wed Aug 11 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR SOUTH CENTRAL BERKS COUNTY...
At 607 PM EDT, a severe thunderstorm was located over Sinking Spring,
or near Reading, moving east at 25 mph.
HAZARD...60 mph wind gusts and quarter size hail.
SOURCE...Radar indicated.
IMPACT...Minor damage to vehicles is possible. Wind damage to roofs,
siding, trees, and power lines is possible.
Locations impacted include...
Reading, Wyomissing, Birdsboro, Sinking Spring, Womelsdorf,
Wernersville, Robesonia, New Morgan, Spring Ridge, Shillington, West
Reading, Mount Penn, Mohnton, Kenhorst, St. Lawrence, Wyomissing
Hills, West Lawn, Lorane, Reiffton and Whitfield.
This includes the following highways...
Pennsylvania Turnpike between mile markers 296 and 299.
Interstate 176 in Pennsylvania between mile markers 1 and 11.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4036 7575 4014 7587 4031 7614 4036 7621
TIME...MOT...LOC 2207Z 274DEG 22KT 4029 7599
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
JEO939
WWUS51 KPHI 112227
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
627 PM EDT Wed Aug 11 2021
PAC011-112245-
/O.CON.KPHI.SV.W.0249.000000T0000Z-210811T2245Z/
Berks PA-
627 PM EDT Wed Aug 11 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR SOUTH CENTRAL BERKS COUNTY...
At 627 PM EDT, a severe thunderstorm was located over Birdsboro, or
near Reading, moving east at 25 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Reading, Wyomissing, Birdsboro, Sinking Spring, Wernersville, New
Morgan, Spring Ridge, Shillington, West Reading, Mount Penn, Mohnton,
Kenhorst, St. Lawrence, Wyomissing Hills, West Lawn, Lorane,
Reiffton, Whitfield, West Wyomissing and Flying Hills.
This includes the following highways...
Pennsylvania Turnpike between mile markers 296 and 299.
Interstate 176 in Pennsylvania between mile markers 1 and 11.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.
&&
LAT...LON 4036 7575 4014 7587 4030 7612 4036 7608
TIME...MOT...LOC 2227Z 274DEG 22KT 4028 7583
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
JEO361
WWUS51 KPHI 112238
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
638 PM EDT Wed Aug 11 2021
PAC011-112248-
/O.EXP.KPHI.SV.W.0249.000000T0000Z-210811T2245Z/
Berks PA-
638 PM EDT Wed Aug 11 2021
...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL BERKS COUNTY
WILL EXPIRE AT 645 PM EDT...
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.
A Severe Thunderstorm Watch remains in effect until 900 PM EDT for
eastern Pennsylvania.
LAT...LON 4036 7575 4014 7587 4030 7612 4036 7608
TIME...MOT...LOC 2238Z 274DEG 22KT 4049 7574
$$
JEOThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 10, 8:02 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 43 min |
| Aug 10, 8:18 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery | 42 min |
| Aug 10, 8:36 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 39 min |
| Aug 10, 8:43 PM EDT | Areal Flood Advisory | PHI | Delaware, Montgomery, Philadelphia | 2 hr |
| Aug 11, 2:56 PM EDT | Excessive Heat Watch | PHI | Berks, Bucks, Chester, Lehigh, Montgomery, Northampton | 12 hr |
| Aug 11, 4:46 PM EDT | Special Weather Statement | PHI | Monroe | 44 min |
| Aug 11, 4:58 PM EDT | Special Weather Statement | PHI | Berks | 47 min |
| Aug 11, 5:20 PM EDT | Areal Flood Advisory | PHI | Carbon, Monroe | 57 min |
| Aug 11, 6:16 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh, Montgomery | 44 min |
| Aug 11, 6:26 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Delaware, Montgomery | 49 min |
| Aug 11, 6:48 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Lehigh, Montgomery, Northampton | 42 min |
| Aug 11, 6:50 PM EDT | Areal Flood Advisory | PHI | Monroe, Northampton | 3 hr |
| Aug 11, 7:04 PM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more | 2 hr |
| Aug 11, 7:11 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 49 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2021Every severe thunderstorm warning 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.