Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 248, NWS Philadelphia/Mount Holly

August 23, 2020New Castle County, Delaware; Chester County, Delaware County, Pennsylvania; Cecil County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 23, 2020, 8:42 PM EDT for New Castle County, Delaware; Chester County, Delaware County, Pennsylvania; Cecil County, Maryland. It was in force for 48 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: Aug 23, 2020, 8:42 PM EDT (00:42 UTC)
Expired: Aug 23, 2020, 9:30 PM EDT
In force: 48 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties New Castle County, DE, Cecil County, MD, Chester County, PA, Delaware County, PA

The radar

The Dover AFB radar (KDOX), 99 km from the middle of the area, began a volume at 00:44 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
Aug 23, 8:45 PM EDT	TSTM WND DMG	1 Nnw Elk Twp, PA	DOWNED TREES AND WIRES NEAR CAMP BONSUL ROAD IN ELK TWP. TIME ESTIMATED FROM RADAR.
Aug 23, 8:46 PM EDT	TSTM WND DMG	1 E Gum Tree, PA	LARGE TREE DOWN BLOCKING DOE RUN STATION ROAD. TIME ESTIMATED FROM RADAR AND DISPATCH REPORT.
Aug 23, 8:54 PM EDT	TSTM WND DMG	Ladenberg, PA	DOWNED TREES AND WIRES NEAR THE INTERSECTION OF PENN GREEN ROAD AND CHESTERVILLE ROAD IN LADENBERG. TIME ESTIMATED FROM RADAR.
Aug 23, 9:10 PM EDT	TSTM WND DMG	2 Ese Kennett Square, PA	DOWNED TREES AND WIRES NEAR HILLENDALE ROAD EAST OF KENNETT SQUARE. TIME ESTIMATED FROM RADAR.
Aug 23, 9:14 PM EDT	TSTM WND DMG	Richardson Park, DE	DOWNED POWER LINES NEAR MARYLAND AVENUE. 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 00:00Z, 0.7 hours before the alert went out and 171 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: 1662 J/kg
Mixed-layer CIN: -6 J/kg
Mixed-layer LCL: 1308 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 59 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

885 
WUUS51 KPHI 240042
SVRPHI
DEC003-MDC015-PAC029-045-240130-
/O.NEW.KPHI.SV.W.0248.200824T0042Z-200824T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
842 PM EDT Sun Aug 23 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern New Castle County in northern Delaware...
  Northeastern Cecil County in northeastern Maryland...
  Southeastern Chester County in southeastern Pennsylvania...
  Southwestern Delaware County in southeastern Pennsylvania...

* Until 930 PM EDT.

* At 842 PM EDT, severe thunderstorms were located along a line
  extending from near West Grove to Blake to Pleasant Hill to
  Brantwood, moving east at 30 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Wilmington, Newark, West Chester, Elkton, Pennsville, Westtown,
  Carneys Point, Elsmere, Kennett Square, New Castle, Penns Grove,
  North East, West Grove, Delaware City, Newport, Arden, Blake,
  Stanton, Cheyney and Glasgow.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 23.
 Interstate 95 in Maryland between mile markers 100 and 109.

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.

In addition to damaging winds, frequent cloud to ground lightning is 
occurring with these storms. Move indoors immediately. Remember, if 
you can hear thunder, you are close enough to be struck by lightning.

&&

LAT...LON 3993 7592 3997 7544 3982 7545 3971 7548
      3969 7551 3963 7556 3960 7555 3958 7551
      3954 7554 3953 7553 3952 7588 3963 7597
      3972 7598
TIME...MOT...LOC 0042Z 256DEG 26KT 3986 7584 3974 7589 3965 7589 3955
7583

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

Gorse

2 follow-up statements

313 
WWUS51 KPHI 240058
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
858 PM EDT Sun Aug 23 2020

DEC003-MDC015-PAC029-045-240130-
/O.CON.KPHI.SV.W.0248.000000T0000Z-200824T0130Z/
New Castle DE-Cecil MD-Chester PA-Delaware PA-
858 PM EDT Sun Aug 23 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR NORTHERN NEW CASTLE...NORTHEASTERN CECIL...SOUTHEASTERN CHESTER
AND SOUTHWESTERN DELAWARE COUNTIES...

At 858 PM EDT, a severe thunderstorm was located over Pike Creek, or
near Newark, moving east at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Wilmington, Newark, Elkton, Pennsville, Carneys Point, Elsmere,
Kennett Square, New Castle, Penns Grove, West Grove, Delaware City,
Newport, Arden, Barksdale, Stanton, North Star, Glasgow, Bear,
Talleyville and Wilmington Manor.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 21.
 Interstate 95 in Maryland between mile markers 104 and 109.

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.

Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.

&&

LAT...LON 3992 7582 3993 7544 3984 7545 3971 7548
      3969 7551 3963 7556 3960 7555 3958 7551
      3954 7554 3961 7588 3970 7589
TIME...MOT...LOC 0058Z 272DEG 26KT 3972 7572 

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

Gorse

126 
WWUS51 KPHI 240112
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
912 PM EDT Sun Aug 23 2020

DEC003-MDC015-PAC029-045-240130-
/O.CON.KPHI.SV.W.0248.000000T0000Z-200824T0130Z/
New Castle DE-Cecil MD-Chester PA-Delaware PA-
912 PM EDT Sun Aug 23 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR NORTHERN NEW CASTLE...NORTHEASTERN CECIL...SOUTH CENTRAL CHESTER
AND SOUTHWESTERN DELAWARE COUNTIES...

At 911 PM EDT, a severe thunderstorm was located over Elsmere, or
near Wilmington, moving east at 30 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Wilmington, Newark, Elkton, Pennsville, Carneys Point, Elsmere,
Kennett Square, New Castle, Penns Grove, Newport, Arden, Stanton,
North Star, Talleyville, Wilmington Manor, Pike Creek, Glen Westover,
Ashland, Greenville and Delaware Memorial Bridge.

This includes the following highways...
 Interstate 95 in Delaware between mile markers 0 and 21.
 Interstate 95 in Maryland near mile marker 109.

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.

Frequent cloud to ground lightning is occurring with this storm. Move
indoors immediately. Lightning is one of nature's leading killers.
Remember, if you can hear thunder, you are close enough to be struck
by lightning.

&&

LAT...LON 3984 7580 3986 7545 3984 7545 3971 7548
      3969 7551 3963 7556 3962 7581
TIME...MOT...LOC 0111Z 256DEG 26KT 3974 7559 

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

Gorse

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 23, 8:30 PM EDT	Special Weather Statement	PHI	New Castle	30 min
Aug 23, 8:48 PM EDT	Special Weather Statement	PHI	New Castle	27 min
Aug 23, 9:14 PM EDT	Special Weather Statement	PHI	New Castle	31 min
Aug 23, 8:20 PM EDT	Special Weather Statement	PHI	Chester	25 min
Aug 24, 1:15 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Lehigh, Monroe, Northampton	21 min
Aug 24, 1:48 PM EDT	Special Weather Statement	PHI	Northampton	27 min
Aug 24, 2:20 PM EDT	Special Weather Statement	PHI	Northampton	25 min
Aug 24, 4:05 PM EDT	Areal Flood Advisory	PHI	Carbon, Monroe	2 hr
Aug 24, 4:08 PM EDT	Special Weather Statement	PHI	Monroe	37 min
Aug 24, 4:38 PM EDT	Severe Thunderstorm Warning	PHI	Carbon, Monroe, Northampton	37 min
Aug 24, 5:01 PM EDT	Special Weather Statement	PHI	Carbon	29 min
Aug 24, 5:11 PM EDT	Special Weather Statement	PHI	Northampton	34 min
Aug 24, 5:40 PM EDT	Special Weather Statement	PHI	Northampton	35 min
Aug 24, 6:05 PM EDT	Special Weather Statement	PHI	Berks	25 min
Aug 24, 6:14 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Northampton	19 min
Aug 24, 3:32 PM EDT	Special Weather Statement	PHI	Queen Anne's	28 min
Aug 24, 3:56 PM EDT	Special Weather Statement	PHI	Kent	34 min

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2020 Severe Thunderstorm Warnings in Delaware, 2020 Severe Thunderstorm Warnings in Maryland, 2020 Every severe thunderstorm warning in 2020

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.