Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 147, NWS Philadelphia/Mount Holly

July 8, 2021Berks County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 8, 2021, 4:06 PM EDT for Berks County, Montgomery County, Pennsylvania. It was in force for 39 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
Jul 8, 2021, 4:06 PM EDT (20:06 UTC)
Expired
Jul 8, 2021, 4:45 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Berks County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 126 km from the middle of the area, began a volume at 20:09 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 8, 4:06 PM EDTTSTM WND DMGRobeson Twp, PATREES WERE DOWNED IN ROBESON TWP. TIME ESTIMATED FROM RADAR.
Jul 8, 4:40 PM EDTTSTM WND DMGWashington Twp, PATREES WERE DOWNED IN WASHINGTON TWP. 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 8, 2:09 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.1 hours before the alert went out and 214 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 2021-07-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 272 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 2021-07-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 18 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
272 J/kg
Mixed-layer CIN
-99 J/kg
Mixed-layer LCL
1291 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
18 m²/s²
0-3 km storm-relative helicity
96 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

298 
WUUS51 KPHI 082006
SVRPHI
PAC011-091-082045-
/O.NEW.KPHI.SV.W.0147.210708T2006Z-210708T2045Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
406 PM EDT Thu Jul 8 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Eastern Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...

* Until 445 PM EDT.

* At 406 PM EDT, a severe thunderstorm was located over Birdsboro, or
  near Reading, moving northeast 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, Birdsboro, Kutztown, Fleetwood, Topton, Bally,
  Bechtelsville, Lyons, New Morgan, Boyertown, Mount Penn, St.
  Lawrence, Lorane, Reiffton, Amity Gardens and Flying Hills.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 43 and 44.
 Interstate 176 in Pennsylvania between mile markers 5 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 4060 7577 4043 7550 4018 7583 4023 7597
TIME...MOT...LOC 2006Z 215DEG 21KT 4026 7586 

HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann
2 follow-up statements
410 
WWUS51 KPHI 082019
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
419 PM EDT Thu Jul 8 2021

PAC011-091-082045-
/O.CON.KPHI.SV.W.0147.000000T0000Z-210708T2045Z/
Berks PA-Montgomery PA-
419 PM EDT Thu Jul 8 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR EASTERN BERKS AND NORTHWESTERN MONTGOMERY COUNTIES...

At 419 PM EDT, a severe thunderstorm was located near Birdsboro, or 8
miles east of Reading, moving northeast 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...
Birdsboro, Kutztown, Fleetwood, Topton, Bally, Bechtelsville, Lyons,
Boyertown, St. Lawrence, Amity Gardens, Lorane and Reiffton.

This includes Interstate 78 in Pennsylvania between mile markers 43
and 44.
 
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 4060 7577 4043 7550 4023 7576 4029 7589
TIME...MOT...LOC 2019Z 217DEG 21KT 4031 7577 

HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann
752 
WWUS51 KPHI 082029
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
429 PM EDT Thu Jul 8 2021

PAC011-091-082045-
/O.CON.KPHI.SV.W.0147.000000T0000Z-210708T2045Z/
Berks PA-Montgomery PA-
429 PM EDT Thu Jul 8 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM EDT
FOR NORTHEASTERN BERKS AND NORTHWESTERN MONTGOMERY COUNTIES...

At 429 PM EDT, a severe thunderstorm was located near Bechtelsville,
or 12 miles east of Reading, moving northeast 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...
Kutztown, Topton, Bally, Bechtelsville, Lyons and Boyertown. 

This includes Interstate 78 in Pennsylvania between mile markers 43
and 44.
 
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 4028 7570 4037 7582 4060 7577 4043 7550
TIME...MOT...LOC 2029Z 216DEG 22KT 4036 7570 

HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 7, 11:11 PM EDTSpecial Weather StatementPHIMonroe49 min
Jul 8, 8:53 AM EDTSpecial Weather StatementPHIMonroe52 min
Jul 8, 9:31 AM EDTAreal Flood AdvisoryPHICarbon, Monroe119 min
Jul 8, 9:46 AM EDTSpecial Weather StatementPHIMonroe44 min
Jul 8, 1:49 PM EDTSevere Thunderstorm WarningPHIBucks41 min
Jul 8, 3:50 PM EDTSpecial Weather StatementPHIBerks25 min
Jul 8, 4:25 PM EDTSevere Thunderstorm WarningPHIBerks50 min
Jul 8, 4:45 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery, Northampton45 min
Jul 8, 4:51 PM EDTSevere Thunderstorm WarningPHIBerks54 min
Jul 8, 5:11 PM EDTSpecial Weather StatementPHILehigh34 min
Jul 8, 5:21 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery, Philadelphia39 min
Jul 8, 5:29 PM EDTSpecial Weather StatementPHINorthampton46 min
Jul 8, 5:52 PM EDTSpecial Weather StatementPHIBerks23 min
Jul 8, 6:06 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery39 min
Jul 8, 6:16 PM EDTSevere Thunderstorm WarningPHINorthampton44 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.