Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 49, NWS Philadelphia/Mount Holly

June 4, 20214 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 4, 2021, 2:21 PM EDT for 4 counties in Pennsylvania. It was in force for 21 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: Jun 4, 2021, 2:21 PM EDT (18:21 UTC)
Expired: Jun 4, 2021, 2:42 PM EDT
In force: 21 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Berks County, PA, Bucks County, PA, Lehigh County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 117 km from the middle of the area, began a volume at 18:21 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
Jun 4, 2:31 PM EDT	TSTM WND DMG	1 S Earl Twp, PA	WIRES DOWN ON VEHICLE ON LONG LANE RD. TIME ESTIMATED FROM RADAR AND DISPATCH REPORT.
Jun 4, 2:41 PM EDT	TSTM WND DMG	4 Nne New Hanover Twp, PA	DOWNED TREE ON DEEP CREEK ROAD NEAR ERB ROAD. TIME ESTIMATED FROM RADAR.

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, 6.4 hours before the alert went out and 218 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: 381 J/kg
Mixed-layer CIN: -55 J/kg
Mixed-layer LCL: 947 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: -8 m²/s²
0-3 km storm-relative helicity: 73 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.1

Open this sounding in Storm Lab

The text

As transmitted.

025 
WUUS51 KPHI 041821
SVRPHI
PAC011-017-077-091-041900-
/O.NEW.KPHI.SV.W.0049.210604T1821Z-210604T1900Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
221 PM EDT Fri Jun 4 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  East central Berks County in eastern Pennsylvania...
  Southeastern Lehigh County in eastern Pennsylvania...
  Northwestern Montgomery County in southeastern Pennsylvania...
  West central Bucks County in southeastern Pennsylvania...

* Until 300 PM EDT.

* At 220 PM EDT, a severe thunderstorm was located near
  Bechtelsville, or 12 miles east of Reading, moving east at 40 mph.

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

  SOURCE...Public.

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

* Locations impacted include...
  East Greenville, Bally, Bechtelsville, Green Lane, Spring Mount,
  Gilbertsville, Zionsville, Geryville, Boyertown, Pennsburg and Red
  Hill.

This includes Northeast Extension between mile markers 44 and 48.
 
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 4034 7584 4047 7577 4050 7540 4027 7546
TIME...MOT...LOC 1820Z 274DEG 36KT 4040 7571 

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

Davis

2 follow-up statements

962 
WWUS51 KPHI 041830
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
230 PM EDT Fri Jun 4 2021

PAC011-017-077-091-041900-
/O.CON.KPHI.SV.W.0049.000000T0000Z-210604T1900Z/
Berks PA-Lehigh PA-Montgomery PA-Bucks PA-
230 PM EDT Fri Jun 4 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 PM EDT
FOR EAST CENTRAL BERKS...SOUTHEASTERN LEHIGH...NORTHWESTERN
MONTGOMERY AND WEST CENTRAL BUCKS COUNTIES...

At 230 PM EDT, a severe thunderstorm was located over Bally, or 15
miles south of Allentown, moving east at 40 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...
East Greenville, Bally, Bechtelsville, Green Lane, Spring Mount,
Gilbertsville, Zionsville, Geryville, Boyertown, Pennsburg and Red
Hill.

This includes Northeast Extension between mile markers 44 and 48.
 
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 4032 7576 4047 7571 4050 7540 4027 7546
TIME...MOT...LOC 1830Z 274DEG 36KT 4039 7558 

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

Davis

841 
WWUS51 KPHI 041842
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
242 PM EDT Fri Jun 4 2021

PAC011-017-077-091-041852-
/O.CAN.KPHI.SV.W.0049.000000T0000Z-210604T1900Z/
Berks PA-Lehigh PA-Montgomery PA-Bucks PA-
242 PM EDT Fri Jun 4 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL BERKS...
SOUTHEASTERN LEHIGH...NORTHWESTERN MONTGOMERY AND WEST CENTRAL BUCKS
COUNTIES IS CANCELLED...
                
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 has been cancelled.

LAT...LON 4032 7576 4047 7571 4050 7540 4027 7546
TIME...MOT...LOC 1841Z 274DEG 36KT 4038 7542 

$$

JEO

The office that day

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

Issued	Product	Office	Counties	Lasted
Jun 3, 8:44 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	30 min
Jun 4, 1:02 PM EDT	Special Weather Statement	PHI	Lehigh	28 min
Jun 4, 1:07 PM EDT	Special Weather Statement	PHI	Carbon, Monroe	38 min
Jun 4, 1:29 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh	2 hr
Jun 4, 1:45 PM EDT	Areal Flood Advisory	PHI	Monroe, Northampton	97 min
Jun 4, 1:49 PM EDT	Severe Thunderstorm Warning	PHI	Monroe, Northampton	41 min
Jun 4, 2:24 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery	51 min
Jun 4, 2:27 PM EDT	Severe Thunderstorm Warning	PHI	Berks	48 min
Jun 4, 3:14 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	46 min
Jun 4, 3:16 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	98 min
Jun 4, 3:18 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	42 min
Jun 4, 3:23 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	67 min
Jun 4, 3:46 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Philadelphia	44 min
Jun 4, 4:20 PM EDT	Severe Thunderstorm Warning	PHI	Philadelphia	40 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.