Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 34, NWS Philadelphia/Mount Holly

May 26, 2021Chester County, Pennsylvania

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 26, 2021, 5:37 PM EDT for Chester County, Pennsylvania. It was in force for 53 min. 5 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: May 26, 2021, 5:37 PM EDT (21:37 UTC)
Expired: May 26, 2021, 6:30 PM EDT
In force: 53 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Chester County, PA

The radar

The Dover AFB radar (KDOX), 119 km from the middle of the area, began a volume at 21:40 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
May 26, 5:44 PM EDT	TSTM WND DMG	Oxford, PA	DOWNED TREES AND WIRES NEAR SIXTH STREET AND MARKET STREET. TIME ESTIMATED FROM RADAR.
May 26, 5:49 PM EDT	TSTM WND DMG	Lincoln University, PA	DOWNED WIRES NEAR LOOP ROAD. TIME ESTIMATED FROM RADAR.
May 26, 5:52 PM EDT	TSTM WND DMG	Londonderry Twp, PA	DOWNED TREE LIMBS AND WIRES NEAR MINDY DRIVE. TIME ESTIMATED FROM RADAR.
May 26, 5:54 PM EDT	TSTM WND DMG	Londonderry Twp, PA	DOWNED TREE LIMBS AND WIRES NEAR DALEVILLE ROAD. TIME ESTIMATED FROM RADAR.
May 26, 6:00 PM EDT	TSTM WND GST 48	West Grove, PA	DEOS MEASURED GUST.

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
May 26, 2:48 PM EDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.6 hours before the alert went out and 157 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: 478 J/kg
Mixed-layer CIN: -132 J/kg
Mixed-layer LCL: 922 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 35 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

381 
WUUS51 KPHI 262137
SVRPHI
PAC029-262230-
/O.NEW.KPHI.SV.W.0034.210526T2137Z-210526T2230Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
537 PM EDT Wed May 26 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southern Chester County in southeastern Pennsylvania...

* Until 630 PM EDT.

* At 537 PM EDT, a severe thunderstorm was located over Mount Vernon,
  or 17 miles northwest of Newark, moving east at 40 mph.

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

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  West Chester, Coatesville, Westtown, Downingtown, Kennett Square,
  Oxford, Parkesburg, West Grove, Homeville, Glen Roy, Cochranville,
  Mount Vernon, Marshallton, Ladenberg, Kemblesville, North Star,
  Hockessin, West Goshen, Atglen and South Coatesville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

&&

LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3983 7604 3987 7599 3997 7599
      4004 7594 4000 7548 3982 7565 3977 7575
      3972 7577 3972 7613
TIME...MOT...LOC 2137Z 258DEG 35KT 3981 7603 

HAIL...0.75IN
WIND...60MPH
 
$$

Meola

3 follow-up statements

859 
WWUS51 KPHI 262155
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
555 PM EDT Wed May 26 2021

PAC029-262230-
/O.CON.KPHI.SV.W.0034.000000T0000Z-210526T2230Z/
Chester PA-
555 PM EDT Wed May 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR SOUTHERN CHESTER COUNTY...

At 555 PM EDT, a severe thunderstorm was located near West Grove, or
13 miles southwest of West Chester, moving east at 35 mph.

HAZARD...70 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
West Chester, Coatesville, Westtown, Downingtown, Kennett Square,
Oxford, Parkesburg, West Grove, Homeville, Glen Roy, Cochranville,
Mount Vernon, Marshallton, Ladenberg, Kemblesville, North Star,
Hockessin, West Goshen, Atglen and South Coatesville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

&&

LAT...LON 3974 7612 3973 7610 3974 7610 3976 7606
      3981 7603 3983 7604 3987 7599 3997 7599
      4004 7594 4000 7548 3982 7565 3977 7575
      3972 7577 3972 7613
TIME...MOT...LOC 2155Z 264DEG 33KT 3988 7583 

HAIL...<.75IN
WIND...70MPH
 
$$

Deal

361 
WWUS51 KPHI 262217
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
617 PM EDT Wed May 26 2021

PAC029-262230-
/O.CON.KPHI.SV.W.0034.000000T0000Z-210526T2230Z/
Chester PA-
617 PM EDT Wed May 26 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 630 PM EDT
FOR SOUTHEASTERN CHESTER COUNTY...

At 617 PM EDT, a severe thunderstorm was located near Elam, or near
West Chester, moving east at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
West Chester, Westtown, Kennett Square, West Grove, Marshallton,
Ladenberg, Kemblesville, North Star, Hockessin, West Goshen, Avondale
and Toughkenamon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

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

To report severe weather contact your nearest law enforcement agency.
They will send your report to the National Weather Service office in
Mount Holly NJ.

&&

LAT...LON 3996 7576 4000 7548 3982 7565 3977 7575
      3972 7577 3972 7596
TIME...MOT...LOC 2217Z 266DEG 30KT 3986 7561 

HAIL...<.75IN
WIND...60MPH
 
$$

Deal

692 
WWUS51 KPHI 262223
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
623 PM EDT Wed May 26 2021

PAC029-262233-
/O.EXP.KPHI.SV.W.0034.000000T0000Z-210526T2230Z/
Chester PA-
623 PM EDT Wed May 26 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CHESTER COUNTY
WILL EXPIRE AT 630 PM EDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.

A Severe Thunderstorm Watch remains in effect until 1000 PM EDT for
northern Delaware...and southeastern Pennsylvania.

To report severe weather, contact your nearest law enforcement
agency. They will relay your report to the National Weather Service
Mount Holly NJ.

LAT...LON 3996 7576 4000 7548 3982 7565 3977 7575
      3972 7577 3972 7596
TIME...MOT...LOC 2223Z 258DEG 35KT 3987 7554 

$$

Deal

The office that day

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

Issued	Product	Office	Counties	Lasted
May 26, 3:39 PM EDT	Severe Thunderstorm Warning	PHI	Berks	56 min
May 26, 4:10 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh	65 min
May 26, 4:46 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	44 min
May 26, 4:52 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery	38 min
May 26, 5:27 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Montgomery, Philadelphia	48 min
May 26, 5:34 PM EDT	Severe Thunderstorm Warning	PHI	Northampton	41 min
May 26, 5:53 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Montgomery, Philadelphia	67 min
May 26, 6:52 PM EDT	Severe Thunderstorm Warning	PHI	Berks	38 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.