Alert archive / Maryland / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 270, NWS Philadelphia/Mount Holly

August 28, 2020Cecil County, Kent County, Maryland; Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 28, 2020, 2:40 PM EDT for Cecil County, Kent County, Maryland; Kent County, New Castle County, Delaware. It was in force for 50 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
Aug 28, 2020, 2:40 PM EDT (18:40 UTC)
Expired
Aug 28, 2020, 3:30 PM EDT
In force
50 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.5 in
Wind
60.0 mph

Counties Kent County, DE, New Castle County, DE, Cecil County, MD, Kent County, MD

The radar

The Dover AFB radar (KDOX), 68 km from the middle of the area, began a volume at 18:43 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

TimeReportWhereRemark
Aug 28, 2:43 PM EDTTSTM WND DMGCecilton, MDSEVERAL REPORTS OF DOWNED TREES AND WIRES IN THE CECILTON AREA. TIME ESTIMATED FROM RADAR.
Aug 28, 2:45 PM EDTTSTM WND DMGWarwick, MDSEVERAL REPORTS OF DOWNED TREES AND WIRES IN THE WARWICK AREA. TIME ESTIMATED FROM RADAR.

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.

IssuedProductOfficeLasted
Aug 28, 1:37 PM EDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.7 hours before the alert went out and 152 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2020-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 511 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2020-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
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
511 J/kg
Mixed-layer CIN
-119 J/kg
Mixed-layer LCL
1109 m above ground
0-6 km bulk shear
24 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

207 
WUUS51 KPHI 281840
SVRPHI
DEC001-003-MDC015-029-281930-
/O.NEW.KPHI.SV.W.0270.200828T1840Z-200828T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
240 PM EDT Fri Aug 28 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southwestern New Castle County in northern Delaware...
  Northwestern Kent County in central Delaware...
  Northeastern Kent County in northeastern Maryland...
  Southeastern Cecil County in northeastern Maryland...

* Until 330 PM EDT.

* At 240 PM EDT, a severe thunderstorm was located over Warwick, or
  near Middletown, moving east at 25 mph.

  HAZARD...Ping pong ball size hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Wind 
           damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Middletown, Smyrna, Clayton, Cheswold, Cecilton, Warwick,
  Sassafras, Green Spring, Bohemias Mills, Delaney Corner, Cayots,
  Townsend, Odessa and Chambersville.

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.

Prepare immediately for large hail and damaging winds. People outside
should move immediately to shelter inside a strong building. Stay
away from windows.

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

&&

LAT...LON 3941 7595 3951 7585 3947 7557 3937 7548
      3920 7557
TIME...MOT...LOC 1840Z 290DEG 21KT 3943 7582 

HAIL...1.50IN
WIND...60MPH
 
$$

Staarmann
3 follow-up statements
705 
WWUS51 KPHI 281851
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
251 PM EDT Fri Aug 28 2020

DEC001-003-MDC015-029-281930-
/O.CON.KPHI.SV.W.0270.000000T0000Z-200828T1930Z/
New Castle DE-Kent DE-Kent MD-Cecil MD-
251 PM EDT Fri Aug 28 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR SOUTHWESTERN NEW CASTLE...NORTHWESTERN KENT...NORTHEASTERN KENT
AND SOUTHEASTERN CECIL COUNTIES...

At 250 PM EDT, a severe thunderstorm was located over Warwick, or
near Middletown, moving east at 25 mph.

HAZARD...Two inch hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Wind damage 
         to roofs, siding, trees, and power lines is possible.

Locations impacted include...
Middletown, Smyrna, Clayton, Cheswold, Warwick, Sassafras, Delaney
Corner, Green Spring, Townsend, Odessa and Chambersville.

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.

Prepare immediately for large hail and damaging winds. People outside
should seek shelter inside a well-built structure and away from
windows.

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 3944 7582 3947 7572 3945 7555 3937 7548
      3920 7557 3936 7586
TIME...MOT...LOC 1850Z 290DEG 21KT 3941 7575 

HAIL...2.00IN
WIND...60MPH
 
$$

Staarmann
887 
WWUS51 KPHI 281901
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
301 PM EDT Fri Aug 28 2020

MDC015-029-281911-
/O.CAN.KPHI.SV.W.0270.000000T0000Z-200828T1930Z/
Kent MD-Cecil MD-
301 PM EDT Fri Aug 28 2020

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN KENT AND
SOUTHEASTERN CECIL COUNTIES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

A Severe Thunderstorm Watch remains in effect until 800 PM EDT for
central and northern Delaware.

LAT...LON 3944 7569 3942 7552 3937 7548 3920 7557
      3931 7576 3939 7576
TIME...MOT...LOC 1901Z 290DEG 24KT 3936 7568 

$$

DEC001-003-281930-
/O.CON.KPHI.SV.W.0270.000000T0000Z-200828T1930Z/
New Castle DE-Kent DE-
301 PM EDT Fri Aug 28 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR SOUTHWESTERN NEW CASTLE AND NORTHWESTERN KENT COUNTIES...

At 301 PM EDT, a severe thunderstorm was located near Green Spring,
or near Middletown, moving east at 30 mph.

HAZARD...Two inch hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Wind damage 
         to roofs, siding, trees, and power lines is possible.

Locations impacted include...
Smyrna, Clayton, Cheswold, Green Spring, Townsend and Chambersville. 

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.

Prepare immediately for large hail and damaging winds. People outside
should seek shelter inside a well-built structure and away from
windows.

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 3944 7569 3942 7552 3937 7548 3920 7557
      3931 7576 3939 7576
TIME...MOT...LOC 1901Z 290DEG 24KT 3936 7568 

HAIL...2.00IN
WIND...60MPH
 
$$

Staarmann
496 
WWUS51 KPHI 281922
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
322 PM EDT Fri Aug 28 2020

DEC001-003-281930-
/O.CON.KPHI.SV.W.0270.000000T0000Z-200828T1930Z/
New Castle DE-Kent DE-
322 PM EDT Fri Aug 28 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR SOUTHEASTERN NEW CASTLE AND NORTH CENTRAL KENT COUNTIES...

At 322 PM EDT, a severe thunderstorm was located near Woodland Beach,
or 10 miles north of Dover, moving east at 25 mph.

HAZARD...Two inch hail and 70 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect 
         considerable tree damage. Wind damage is also likely to 
         mobile homes, roofs, and outbuildings.

Locations impacted include...
Smyrna.

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.

Prepare immediately for large hail and damaging winds. People outside
should seek shelter inside a well-built structure and away from
windows.

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 3937 7556 3938 7548 3933 7550 3923 7556
      3926 7563
TIME...MOT...LOC 1922Z 290DEG 21KT 3932 7553 

HAIL...2.00IN
WIND...70MPH
 
$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 28, 1:53 PM EDTSevere Thunderstorm WarningPHICecil, Kent52 min
Aug 28, 4:01 PM EDTSevere Thunderstorm WarningPHICecil44 min
Aug 28, 4:39 PM EDTSevere Thunderstorm WarningPHICecil, Kent, Queen Anne's66 min
Aug 28, 6:17 PM EDTSevere Thunderstorm WarningPHICaroline43 min
Aug 28, 3:15 PM EDTSpecial Weather StatementPHINew Castle30 min
Aug 28, 3:21 PM EDTSevere Thunderstorm WarningPHIKent, New Castle24 min
Aug 28, 3:41 PM EDTSpecial Weather StatementPHINew Castle34 min
Aug 28, 3:52 PM EDTSevere Thunderstorm WarningPHINew Castle53 min
Aug 28, 5:40 PM EDTSpecial Weather StatementPHIKent35 min
Aug 28, 7:53 PM EDTSpecial Weather StatementPHISussex37 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2020Severe Thunderstorm Warnings in Delaware, 2020Every 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.