Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 181, NWS Philadelphia/Mount Holly

July 17, 2021Berks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2021, 2:36 PM EDT for Berks County, Pennsylvania. It was in force for 39 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 17, 2021, 2:36 PM EDT (18:36 UTC)
Expired: Jul 17, 2021, 3:15 PM EDT
In force: 39 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 State College radar (KCCX), 161 km from the middle of the area, began a volume at 18:36 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 17, 1:13 PM EDT	Severe Thunderstorm Watch	SPC	10 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.6 hours before the alert went out and 204 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: 538 J/kg
Mixed-layer CIN: -141 J/kg
Mixed-layer LCL: 1337 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

789 
WUUS51 KPHI 171836
SVRPHI
PAC011-171915-
/O.NEW.KPHI.SV.W.0181.210717T1836Z-210717T1915Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
236 PM EDT Sat Jul 17 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 315 PM EDT.

* At 235 PM EDT, a severe thunderstorm was located over Myerstown,
  moving northeast at 25 mph.

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

  SOURCE...Radar indicated. Downed trees were also reported with 
           this storm in Lebanon County.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Hamburg, Womelsdorf, Bernville and Strausstown. 

This includes Interstate 78 in Pennsylvania between mile markers 10
and 31.
 
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 4052 7634 4052 7625 4056 7609 4058 7606
      4058 7604 4057 7602 4060 7600 4058 7596
      4035 7619 4039 7627 4049 7643
TIME...MOT...LOC 1835Z 208DEG 22KT 4038 7635 

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

JEO

2 follow-up statements

741 
WWUS51 KPHI 171850
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
250 PM EDT Sat Jul 17 2021

PAC011-171915-
/O.CON.KPHI.SV.W.0181.000000T0000Z-210717T1915Z/
Berks PA-
250 PM EDT Sat Jul 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 315 PM EDT
FOR NORTHWESTERN BERKS COUNTY...

At 250 PM EDT, a severe thunderstorm was located near Strausstown, or
near Myerstown, 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...
Strausstown.

This includes Interstate 78 in Pennsylvania between mile markers 10
and 27.
 
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 4052 7634 4052 7625 4056 7609 4058 7606
      4058 7604 4057 7602 4051 7607 4041 7620
      4039 7627 4049 7643
TIME...MOT...LOC 1850Z 208DEG 22KT 4046 7629 

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

JEO

433 
WWUS51 KPHI 171910
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
310 PM EDT Sat Jul 17 2021

PAC011-171920-
/O.EXP.KPHI.SV.W.0181.000000T0000Z-210717T1915Z/
Berks PA-
310 PM EDT Sat Jul 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN BERKS COUNTY WILL
EXPIRE AT 315 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 1100 PM EDT for
eastern Pennsylvania.

LAT...LON 4052 7634 4052 7625 4056 7609 4058 7606
      4058 7604 4057 7602 4051 7607 4041 7620
      4039 7627 4049 7643
TIME...MOT...LOC 1910Z 208DEG 22KT 4067 7545 

$$

JEO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 8:14 PM EDT	Special Weather Statement	PHI	Montgomery	31 min
Jul 16, 8:41 PM EDT	Special Weather Statement	PHI	Bucks	34 min
Jul 16, 9:07 PM EDT	Special Weather Statement	PHI	Lehigh	23 min
Jul 16, 9:29 PM EDT	Special Weather Statement	PHI	Lehigh	31 min
Jul 16, 10:21 PM EDT	Special Weather Statement	PHI	Lehigh	24 min
Jul 17, 12:55 PM EDT	Special Weather Statement	PHI	Bucks	50 min
Jul 17, 1:05 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	40 min
Jul 17, 1:31 PM EDT	Areal Flood Advisory	PHI	Bucks	97 min
Jul 17, 2:30 PM EDT	Special Weather Statement	PHI	Berks	45 min
Jul 17, 3:06 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	39 min
Jul 17, 5:13 PM EDT	Areal Flood Advisory	PHI	Bucks, Montgomery, Philadelphia	4 hr
Jul 17, 5:25 PM EDT	Flash Flood Warning	PHI	Bucks	6 hr
Jul 17, 5:30 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	19 min
Jul 17, 6:02 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	43 min
Jul 17, 6:39 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	51 min
Jul 17, 6:51 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	39 min
Jul 17, 7:01 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	44 min
Jul 17, 7:12 PM EDT	Areal Flood Advisory	PHI	Bucks, Philadelphia	3 hr
Jul 17, 7:26 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	49 min
Jul 17, 7:36 PM EDT	Special Weather Statement	PHI	Carbon	54 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.