Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 122, NWS Philadelphia/Mount Holly

July 6, 2021Berks County, Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 6, 2021, 4:23 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 52 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: Jul 6, 2021, 4:23 PM EDT (20:23 UTC)
Expired: Jul 6, 2021, 5:15 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

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

The radar

The Philadelphia radar (KDIX), 121 km from the middle of the area, began a volume at 20:24 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
Jul 6, 1:32 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.4 hours before the alert went out and 186 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 982 J/kg
Mixed-layer CIN: -161 J/kg
Mixed-layer LCL: 1216 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 38 m²/s²
0-3 km storm-relative helicity: 39 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

127 
WUUS51 KPHI 062023
SVRPHI
PAC011-029-091-062115-
/O.NEW.KPHI.SV.W.0122.210706T2023Z-210706T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
423 PM EDT Tue Jul 6 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southern Berks County in eastern Pennsylvania...
  West central Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...

* Until 515 PM EDT.

* At 422 PM EDT, a severe thunderstorm was located over Honey Brook,
  or 11 miles east of New Holland, 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...
  Pottstown, Phoenixville, Coatesville, Downingtown, Royersford,
  Trappe, Honey Brook, Elverson, New Morgan, Pughtown,
  Lionville-Marchwood, Valley Forge, Glenmoore, Paoli, Chester
  Springs, Lionville, Cedarville, Spring City, Malvern and South
  Pottstown.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 296 and 323.
 Interstate 176 in Pennsylvania between mile markers 1 and 3.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4004 7593 4011 7594 4014 7588 4019 7595
      4027 7549 3999 7545 4000 7595
TIME...MOT...LOC 2022Z 264DEG 23KT 4010 7587 

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

Staarmann

2 follow-up statements

231 
WWUS51 KPHI 062040
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
440 PM EDT Tue Jul 6 2021

PAC011-062050-
/O.CAN.KPHI.SV.W.0122.000000T0000Z-210706T2115Z/
Berks PA-
440 PM EDT Tue Jul 6 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN BERKS 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 Watch remains in effect until 1000 PM EDT for
eastern and southeastern Pennsylvania.

LAT...LON 4017 7582 4023 7548 3999 7545 4002 7583
      4017 7583
TIME...MOT...LOC 2040Z 265DEG 22KT 4009 7575 

$$

PAC029-091-062115-
/O.CON.KPHI.SV.W.0122.000000T0000Z-210706T2115Z/
Montgomery PA-Chester PA-
440 PM EDT Tue Jul 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR WEST CENTRAL MONTGOMERY AND NORTHEASTERN CHESTER COUNTIES...

At 440 PM EDT, a severe thunderstorm was located over Glenmoore, or
11 miles northwest of West Chester, 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...
Phoenixville, Downingtown, Royersford, Trappe, Elverson, Valley
Forge, Glenmoore, Paoli, Chester Springs, Pughtown, Lionville,
Lionville-Marchwood, Spring City, Malvern, Exton, Chesterbrook and
Devon-Berwyn.

This includes Pennsylvania Turnpike between mile markers 302 and 323.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4017 7582 4023 7548 3999 7545 4002 7583
      4017 7583
TIME...MOT...LOC 2040Z 265DEG 22KT 4009 7575 

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

Staarmann

394 
WWUS51 KPHI 062050
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
450 PM EDT Tue Jul 6 2021

PAC029-091-062115-
/O.CON.KPHI.SV.W.0122.000000T0000Z-210706T2115Z/
Montgomery PA-Chester PA-
450 PM EDT Tue Jul 6 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR WEST CENTRAL MONTGOMERY AND NORTHEASTERN CHESTER COUNTIES...

At 450 PM EDT, a severe thunderstorm was located over Chester
Springs, or 9 miles north of West Chester, 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...
Phoenixville, Downingtown, Royersford, Trappe, Valley Forge, Paoli,
Chester Springs, Pughtown, Lionville, Lionville-Marchwood, Spring
City, Malvern, Exton, Chesterbrook and Devon-Berwyn.

This includes Pennsylvania Turnpike between mile markers 307 and 323.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4001 7573 4017 7577 4023 7548 3999 7545
TIME...MOT...LOC 2050Z 264DEG 23KT 4010 7566 

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

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 6, 4:29 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe	76 min
Jul 6, 5:08 PM EDT	Special Weather Statement	PHI	Carbon	37 min
Jul 6, 5:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	49 min
Jul 6, 5:15 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	60 min
Jul 6, 5:34 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery, Philadelphia	41 min
Jul 6, 5:55 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	65 min
Jul 6, 6:13 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	31 min
Jul 6, 6:41 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	64 min
Jul 6, 7:01 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	59 min
Jul 6, 7:50 PM EDT	Special Weather Statement	PHI	Lehigh	25 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2021 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.