Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 204, NWS Philadelphia/Mount Holly

July 21, 2021Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 21, 2021, 1:27 PM EDT for Berks County, Pennsylvania. It was in force for 48 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: Jul 21, 2021, 1:27 PM EDT (17:27 UTC)
Expired: Jul 21, 2021, 2:15 PM EDT
In force: 48 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), 156 km from the middle of the area, began a volume at 17:30 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
Jul 21, 2:00 PM EDT	HAIL 1	Temple, PA
Jul 21, 2:20 PM EDT	TSTM WND DMG	1 Nw West Lawn, PA	PHOTO OF LARGE TREE BRANCHES DOWN ON WIRES IN WEST LAWN PA. TIME ESTIMATED BY SPOTTER.
Jul 21, 2:24 PM EDT	TSTM WND DMG	Spring Twp, PA	LARGE BRANCH DOWN 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
Jul 21, 11:56 AM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.5 hours before the alert went out and 199 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: 638 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 1275 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 95 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

950 
WUUS51 KPHI 211727
SVRPHI
PAC011-211815-
/O.NEW.KPHI.SV.W.0204.210721T1727Z-210721T1815Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
127 PM EDT Wed Jul 21 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Berks County in eastern Pennsylvania...

* Until 215 PM EDT.

* At 126 PM EDT, a severe thunderstorm was located over Fairview
  Hgts, or 9 miles northwest of Reading, moving southeast at 20 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, Fleetwood, Sinking Spring,
  Laureldale, Womelsdorf, Wernersville, Robesonia, Leesport,
  Shoemakersville, Bally, Bernville, Bechtelsville, Strausstown, New
  Morgan, Spring Ridge, Fairview Hgts, Shillington and West Reading.

This includes the following highways...
 Interstate 78 in Pennsylvania near mile marker 8, and between mile
markers 10 and 27.
 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.

&&

LAT...LON 4049 7643 4051 7636 4052 7625 4053 7622
      4054 7617 4056 7612 4040 7557 4024 7570
      4017 7582 4040 7629
TIME...MOT...LOC 1726Z 298DEG 18KT 4043 7605 

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

NC

1 follow-up statement

345 
WWUS51 KPHI 211751
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
151 PM EDT Wed Jul 21 2021

PAC011-211815-
/O.CON.KPHI.SV.W.0204.000000T0000Z-210721T1815Z/
Berks PA-
151 PM EDT Wed Jul 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 215 PM EDT
FOR CENTRAL BERKS COUNTY...

At 150 PM EDT, a severe thunderstorm was located over Laureldale, or
just north of Reading, moving southeast at 20 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, Fleetwood, Sinking Spring,
Laureldale, Womelsdorf, Wernersville, Robesonia, Leesport, Bally,
Bernville, Bechtelsville, Strausstown, New Morgan, Spring Ridge,
Fairview Hgts, Shillington, West Reading and Boyertown.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 12 and 22.
 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.

&&

LAT...LON 4045 7637 4048 7632 4049 7629 4051 7613
      4040 7557 4024 7570 4017 7582 4040 7629
TIME...MOT...LOC 1750Z 298DEG 18KT 4037 7591 

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

NC

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 1:08 PM EDT	Special Weather Statement	PHI	Lehigh	37 min
Jul 21, 1:11 PM EDT	Special Weather Statement	PHI	Northampton	34 min
Jul 21, 2:03 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Northampton	42 min
Jul 21, 2:14 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Montgomery	19 min
Jul 21, 2:41 PM EDT	Special Weather Statement	PHI	Montgomery	49 min
Jul 21, 2:48 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	42 min
Jul 21, 2:52 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	38 min
Jul 21, 3:16 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	44 min
Jul 21, 3:27 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Philadelphia	33 min
Jul 21, 3:48 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	42 min
Jul 21, 5:59 PM EDT	Special Weather Statement	PHI	Berks	31 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.