Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 230, NWS Philadelphia/Mount Holly

July 29, 2021Berks County, Lehigh County, Northampton County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 29, 2021, 3:48 PM EDT for Berks County, Lehigh County, Northampton County, Pennsylvania. It was in force for 42 min. 8 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 29, 2021, 3:48 PM EDT (19:48 UTC)
Expired: Jul 29, 2021, 4:30 PM EDT
In force: 42 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 1.0 in
Wind: 60.0 mph

Counties Berks County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 133 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

Time	Report	Where	Remark
Jul 29, 3:50 PM EDT	TSTM WND DMG	2 E Albany Twp, PA	SEVERAL TREES DOWN IN KEMPTON. TIME ESTIMATED FROM RADAR.
Jul 29, 4:04 PM EDT	TORNADO	4 N Greenwich Twp, PA	A TORNADO TOUCHED DOWN NEAR TURKEY RD IN KEMPTON, ALBANY TWP, BERKS COUNTY, PA, JUST WEST OF THE BORDER WITH LEHIGH COUNTY. ABOUT 15 TREES WERE UPROOTED IN THE AREA OF TURKEY RD WITH A CONVERGENT DAMAGE PATTERN NOTED IN MULTIPLE NEARBY CORN FIELDS. THE PATH CO
Jul 29, 4:05 PM EDT	TSTM WND DMG	1 Nw Weisenberg Twp, PA	UTILITY POLES DOWN.
Jul 29, 4:05 PM EDT	TSTM WND DMG	New Tripoli, PA	DOWNED TREES AND POWER LINES IN THE NEW TRIPOLI AREA. SOME STRUCTURAL DAMAGE TO AN OUTSIDE BARN AS WELL WITH PIECES OF ROOFING OFF. TIME ESTIMATED FROM RADAR.
Jul 29, 4:06 PM EDT	TORNADO	3 Wnw Weisenberg Twp, PA	A TORNADO TOUCHED DOWN BETWEEN KUNKELS MILL RD AND RED RD NEAR THE FAR SOUTHERN TIP OF LYNN TWP IN LEHIGH COUNTY, PENNSYLVANIA, JUST EAST OF THE COUNTY LINE WITH BERKS COUNTY. MOSTLY MINOR CROP AND TREE DAMAGE WAS OBSERVED IN THIS AREA, BUT WITH A CLEAR CONVER
Jul 29, 4:14 PM EDT	TSTM WND DMG	1 Ese Weisenberg Twp, PA	TREES AND WIRES DOWN ON 863. ROUTE 863 IS CLOSED DUE TO DEBRIS.
Jul 29, 4:15 PM EDT	TSTM WND DMG	1 Nw Weisenberg Twp, PA	TREES AND WIRES DOWN WITH PARTIALLY TORN OFF ROOF OF A BUILDING. POSSIBLE TORNADO DAMAGE. TIME ESTIMATED BY RADAR.
Jul 29, 4:40 PM EDT	TSTM WND GST 42	West Catasauqua, PA	MEASURED 42 MPH WIND GUST AND PEA-SIZED HAIL IN WHITEHALL TOWNSHIP, PA.

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 29, 2:23 PM EDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 7.8 hours before the alert went out and 231 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: 269 J/kg
Mixed-layer CIN: -91 J/kg
Mixed-layer LCL: 893 m above ground
0-6 km bulk shear: 39 kt
0-1 km storm-relative helicity: 62 m²/s²
0-3 km storm-relative helicity: 62 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

339 
WUUS51 KPHI 291948
SVRPHI
PAC011-077-095-292030-
/O.NEW.KPHI.SV.W.0230.210729T1948Z-210729T2030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
348 PM EDT Thu Jul 29 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northeastern Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Southwestern Northampton County in eastern Pennsylvania...

* Until 430 PM EDT.

* At 348 PM EDT, a severe thunderstorm was located over
  Lenhartsville, or 14 miles east of Schuylkill Haven, 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...
  Allentown, Bethlehem, Emmaus, Northampton, Kutztown, Hamburg,
  Topton, Shoemakersville, Lyons, Lenhartsville, Neffs, Coffeetown,
  New Tripoli, Zionsville, Ancient Oaks, Claussville, Wanamakers,
  Schnecksville, Catasauqua and Coplay.

This includes the following highways...
 Northeast Extension between mile markers 46 and 66.
 Interstate 78 in Pennsylvania between mile markers 32 and 62.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for eastern
Pennsylvania.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

&&

LAT...LON 4065 7597 4075 7542 4048 7542 4046 7544
      4047 7597 4065 7598
TIME...MOT...LOC 1948Z 261DEG 22KT 4059 7590 

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

Fitzsimmons

1 follow-up statement

633 
WWUS51 KPHI 292009
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
409 PM EDT Thu Jul 29 2021

PAC011-077-095-292030-
/O.CON.KPHI.SV.W.0230.000000T0000Z-210729T2030Z/
Berks PA-Lehigh PA-Northampton PA-
409 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 430 PM EDT
FOR NORTHEASTERN BERKS...LEHIGH AND SOUTHWESTERN NORTHAMPTON
COUNTIES...

At 407 PM EDT, a severe thunderstorm was located near Wanamakers, or
15 miles south of Lehighton, moving east at 25 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Allentown, Bethlehem, Emmaus, Northampton, Kutztown, Topton,
Lenhartsville, Neffs, Wanamakers, Coffeetown, New Tripoli, Ancient
Oaks, Schnecksville, Claussville, Catasauqua, Coplay, Macungie, North
Catasauqua, Alburtis and Fullerton.

This includes the following highways...
 Northeast Extension between mile markers 50 and 66.
 Interstate 78 in Pennsylvania between mile markers 36 and 62.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for eastern
Pennsylvania.

Remain alert for a possible tornado! Much of this warned area is 
also currently under a Tornado Warning. If you spot a tornado go at 
once into the basement or small central room in a sturdy structure.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4051 7591 4066 7591 4067 7586 4075 7542
      4050 7542
TIME...MOT...LOC 2007Z 257DEG 20KT 4062 7578 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...70MPH
 
$$

Fitzsimmons

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 4:03 PM EDT	Tornado Warning	PHI	Berks, Lehigh, Northampton	27 min
Jul 29, 4:27 PM EDT	Tornado Warning	PHI	Lehigh, Northampton	16 min
Jul 29, 4:30 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Carbon, Lehigh, Monroe, Northampton	45 min
Jul 29, 4:46 PM EDT	Areal Flood Advisory	PHI	Berks, Lehigh, Northampton	3 hr
Jul 29, 4:56 PM EDT	Tornado Warning	PHI	Bucks, Lehigh, Northampton	34 min
Jul 29, 4:57 PM EDT	Areal Flood Advisory	PHI	Bucks, Monroe, Northampton	3 hr
Jul 29, 5:03 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Monroe, Northampton	42 min
Jul 29, 5:08 PM EDT	Tornado Warning	PHI	Bucks	37 min
Jul 29, 5:27 PM EDT	Areal Flood Advisory	PHI	Bucks	3 hr
Jul 29, 5:32 PM EDT	Flash Flood Warning	PHI	Northampton	2 hr
Jul 29, 5:32 PM EDT	Tornado Warning	PHI	Bucks	28 min
Jul 29, 5:51 PM EDT	Tornado Warning Tornado observedConsiderable damage threat	PHI	Bucks	24 min
Jul 29, 5:58 PM EDT	Flash Flood Warning	PHI	Bucks	3 hr
Jul 29, 6:06 PM EDT	Tornado Warning Considerable damage threat	PHI	Bucks	39 min
Jul 29, 6:21 PM EDT	Special Weather Statement	PHI	Bucks	24 min
Jul 29, 6:45 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	45 min
Jul 29, 7:07 PM EDT	Tornado Warning	PHI	Bucks, Philadelphia	23 min
Jul 29, 7:12 PM EDT	Flash Flood Warning	PHI	Bucks, Philadelphia	4 hr
Jul 29, 7:25 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	50 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.