Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2023

Severe Thunderstorm Warning 285, NWS Philadelphia/Mount Holly

August 12, 2023Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 12, 2023, 3:49 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 41 min. 1 report 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 12, 2023, 3:49 PM EDT (19:49 UTC)
Expired
Aug 12, 2023, 4:30 PM EDT
In force
41 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Berks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 119 km from the middle of the area, began a volume at 19:49 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

TimeReportWhereRemark
Aug 12, 3:56 PM EDTTSTM WND GST 451 S Reading Regional Ai, PAASOS station KRDG Reading.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.8 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.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2023-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 176 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 2023-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 24 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
176 J/kg
Mixed-layer CIN
-108 J/kg
Mixed-layer LCL
1236 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
24 m²/s²
0-3 km storm-relative helicity
103 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

567 
WUUS51 KPHI 121949
SVRPHI
PAC011-029-091-122030-
/O.NEW.KPHI.SV.W.0285.230812T1949Z-230812T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
349 PM EDT Sat Aug 12 2023

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southeastern Berks County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 430 PM EDT.

* At 349 PM EDT, a severe thunderstorm was located over Reading,
  moving east at 30 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Reading, Pottstown, Phoenixville, Wyomissing, Birdsboro,
  Collegeville, Royersford, Sinking Spring, Laureldale, Trappe, East
  Greenville, Leesport, Schwenksville, Bally, Bechtelsville, Green
  Lane, Spring Mount, Gilbertsville, Spring Ridge and Cedarville.

This includes the following highways...
 Northeast Extension between mile markers 36 and 39.
 Interstate 176 in Pennsylvania between mile markers 10 and 11.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4046 7599 4041 7546 4035 7537 4011 7542
      4032 7604
TIME...MOT...LOC 1949Z 280DEG 26KT 4034 7589 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Hoeflich
2 follow-up statements
981 
WWUS51 KPHI 122013
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
413 PM EDT Sat Aug 12 2023

PAC029-122022-
/O.CAN.KPHI.SV.W.0285.000000T0000Z-230812T2030Z/
Chester PA-
413 PM EDT Sat Aug 12 2023

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...
    
The severe 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 until 4:45 PM EDT for central 
Chester County. 

LAT...LON 4045 7586 4042 7553 4021 7555 4022 7559
      4024 7560 4022 7561 4024 7565 4024 7568
      4032 7587
TIME...MOT...LOC 2012Z 274DEG 18KT 4037 7578 

$$

PAC011-091-122030-
/O.CON.KPHI.SV.W.0285.000000T0000Z-230812T2030Z/
Berks PA-Montgomery PA-
413 PM EDT Sat Aug 12 2023

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR EAST CENTRAL BERKS AND NORTHWESTERN MONTGOMERY COUNTIES...

At 412 PM EDT, a severe thunderstorm was located near Fleetwood, or 7
miles east of Reading, moving east at 20 mph.

HAZARD...60 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Pottstown, Bally, Bechtelsville, Gilbertsville, Stowe, Boyertown, St.
Lawrence, Pottsgrove, Amity Gardens, Sanatoga, Halfway House, South
Pottstown, Reiffton and Kenilworth.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 4045 7586 4042 7553 4021 7555 4022 7559
      4024 7560 4022 7561 4024 7565 4024 7568
      4032 7587
TIME...MOT...LOC 2012Z 274DEG 18KT 4037 7578 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Hoeflich
126 
WWUS51 KPHI 122022
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
422 PM EDT Sat Aug 12 2023

PAC011-091-122032-
/O.EXP.KPHI.SV.W.0285.000000T0000Z-230812T2030Z/
Berks PA-Montgomery PA-
422 PM EDT Sat Aug 12 2023

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL BERKS AND
NORTHWESTERN MONTGOMERY COUNTIES WILL EXPIRE AT 430 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 4045 7586 4042 7553 4021 7555 4022 7559
      4024 7560 4022 7561 4024 7565 4024 7568
      4032 7587
TIME...MOT...LOC 2022Z 280DEG 26KT 4036 7570 

$$

Hoeflich

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 12:57 PM EDTAreal Flood AdvisoryPHIDelaware, Philadelphia3 hr
Aug 12, 1:38 PM EDTAreal Flood AdvisoryPHIDelaware, Philadelphia3 hr
Aug 12, 3:06 PM EDTSpecial Weather StatementPHIBerks24 min
Aug 12, 3:39 PM EDTSpecial Weather StatementPHIBerks36 min
Aug 12, 3:55 PM EDTSpecial Weather StatementPHIChester35 min
Aug 12, 4:06 PM EDTSevere Thunderstorm WarningPHIChester, Delaware39 min
Aug 12, 4:37 PM EDTSevere Thunderstorm WarningPHIChester, Delaware38 min
Aug 12, 4:57 PM EDTSevere Thunderstorm WarningPHICarbon48 min
Aug 12, 5:05 PM EDTAreal Flood AdvisoryPHIChester3 hr
Aug 12, 5:16 PM EDTSpecial Weather StatementPHIDelaware29 min
Aug 12, 5:31 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery44 min
Aug 12, 6:42 PM EDTSpecial Weather StatementPHIMontgomery33 min
Aug 12, 6:47 PM EDTSevere Thunderstorm WarningPHIChester, Delaware, Montgomery28 min
Aug 12, 6:58 PM EDTAreal Flood AdvisoryPHIChester3 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2023Every severe thunderstorm warning 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.