Alert archive / Maryland / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 290, NWS Philadelphia/Mount Holly

September 3, 2020Caroline County, Talbot County, Maryland; Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 3, 2020, 6:48 PM EDT for Caroline County, Talbot County, Maryland; Kent County, Sussex County, Delaware. It was in force for 57 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
Sep 3, 2020, 6:48 PM EDT (22:48 UTC)
Expired
Sep 3, 2020, 7:45 PM EDT
In force
57 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Possible
Hail
1.0 in
Wind
70.0 mph

Counties Kent County, DE, Sussex County, DE, Caroline County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 48 km from the middle of the area, began a volume at 22:50 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
Sep 3, 7:19 PM EDTTSTM WND DMGFederalsburg, MDCOUNTY DISPATCH REPORTS 3 CALLS SO FAR FOR DOWNED TREES IN FEDERALSBURG. TIME ESTIMATED FROM RADAR.
Sep 3, 7:21 PM EDTTSTM WND DMG2 Ese Agner, MDDOWNED WIRES ON SMITHVILLE RD. TIME ESTIMATED FROM RADAR.
Sep 3, 7:30 PM EDTTSTM WND DMG4 Wsw Bridgeville, DETREE DOWN ON WIRES NEAR THE INTERSECTION OF FEDERALSBURG RD AND HARTZELL RD. TIME ESTIMATED FROM RADAR.
Sep 3, 7:30 PM EDTTSTM WND DMG5 Wnw Bridgeville, DETREE DOWN ON WIRES NEAR THE INTERSECTION OF WHITNEY SWAMP RD AND BUCK FEVER RD. TIME ESTIMATED FROM RADAR.
Sep 3, 7:33 PM EDTTSTM WND GST 601 S Bridgeville, DETHE SPOTTER ESTIMATED 60 TO 65 MPH WINDS ON THE SOUTH SIDE OF BRIDGEVILLE IN ASSOCIATION WITH A REAR FLANK DOWNDRAFT. 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
Sep 3, 3:42 PM EDTTornado WatchSPC6 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.8 hours before the alert went out and 108 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, Wallops Is Stn, VA at 12:00Z on 2020-09-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 72 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, Wallops Is Stn, VA at 12:00Z on 2020-09-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -21 square meters per square second.1939Sfc1 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
72 J/kg
Mixed-layer CIN
-137 J/kg
Mixed-layer LCL
1124 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-21 m²/s²
0-3 km storm-relative helicity
55 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.9

Open this sounding in Storm Lab

The text

As transmitted.

127 
WUUS51 KPHI 032248
SVRPHI
DEC001-005-MDC011-041-032345-
/O.NEW.KPHI.SV.W.0290.200903T2248Z-200903T2345Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
648 PM EDT Thu Sep 3 2020

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Central Sussex County in southern Delaware...
  Southern Kent County in central Delaware...
  Talbot County in eastern Maryland...
  Caroline County in eastern Maryland...

* Until 745 PM EDT.

* At 647 PM EDT, severe thunderstorms were located along a line
  extending from near Ridgely to near Easton to Talbot, moving east
  at 40 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...
  Easton, Georgetown, Talbot, Milford, Seaford, Denton, Harrington,
  Lewes, Federalsburg, Milton, Bridgeville, Ridgely, St. Michaels,
  Preston, Ellendale, Queen Anne, Smithville, Copperville, Agner and
  Choptank.

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.

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. A Tornado 
Watch remains in effect until 1000 PM EDT for central and southern 
Delaware...and eastern and northeastern Maryland.

In addition to large hail and 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 3886 7626 3885 7626 3879 7620 3886 7619
      3894 7602 3892 7595 3896 7592 3895 7530
      3879 7513 3868 7532 3859 7570 3865 7571
      3871 7584 3865 7596 3872 7623 3876 7622
      3873 7630 3878 7629 3874 7632 3875 7637
TIME...MOT...LOC 2247Z 281DEG 36KT 3891 7588 3883 7605 3880 7628 

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

Staarmann
2 follow-up statements
067 
WWUS51 KPHI 032320
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
720 PM EDT Thu Sep 3 2020

MDC041-032330-
/O.CAN.KPHI.SV.W.0290.000000T0000Z-200903T2345Z/
Talbot MD-
720 PM EDT Thu Sep 3 2020

...THE SEVERE THUNDERSTORM WARNING FOR TALBOT COUNTY IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware...and eastern Maryland.

LAT...LON 3861 7571 3865 7571 3869 7577 3868 7578
      3871 7584 3868 7592 3869 7595 3878 7591
      3890 7581 3895 7530 3879 7513 3868 7532
      3859 7569
TIME...MOT...LOC 2320Z 286DEG 31KT 3883 7571 3874 7576 3869 7581 

$$

DEC001-005-MDC011-032345-
/O.CON.KPHI.SV.W.0290.000000T0000Z-200903T2345Z/
Sussex DE-Kent DE-Caroline MD-
720 PM EDT Thu Sep 3 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR CENTRAL SUSSEX...SOUTHERN KENT AND SOUTHEASTERN CAROLINE
COUNTIES...

At 720 PM EDT, severe thunderstorms were located along a line
extending from near Smithville to near Agner to near Federalsburg,
moving east at 35 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...
Georgetown, Milford, Seaford, Denton, Harrington, Lewes,
Federalsburg, Milton, Bridgeville, Preston, Ellendale, Harmony,
Smithville, Agner, Andrewsville, Blades, Greenwood, Houston and
Farmington.

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.

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. A Tornado 
Watch remains in effect until 1000 PM EDT for central and southern 
Delaware...and eastern Maryland.

Frequent cloud to ground lightning is occurring with these storms.
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 3861 7571 3865 7571 3869 7577 3868 7578
      3871 7584 3868 7592 3869 7595 3878 7591
      3890 7581 3895 7530 3879 7513 3868 7532
      3859 7569
TIME...MOT...LOC 2320Z 286DEG 31KT 3883 7571 3874 7576 3869 7581 

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

Staarmann
571 
WWUS51 KPHI 032336
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
736 PM EDT Thu Sep 3 2020

MDC011-032345-
/O.CAN.KPHI.SV.W.0290.000000T0000Z-200903T2345Z/
Caroline MD-
736 PM EDT Thu Sep 3 2020

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN CAROLINE COUNTY
IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware...and eastern Maryland.

LAT...LON 3865 7571 3885 7572 3893 7527 3879 7513
      3868 7532 3862 7559
TIME...MOT...LOC 2335Z 277DEG 37KT 3882 7556 3874 7556 3866 7563 

$$

DEC001-005-032345-
/O.CON.KPHI.SV.W.0290.000000T0000Z-200903T2345Z/
Sussex DE-Kent DE-
736 PM EDT Thu Sep 3 2020

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR CENTRAL SUSSEX AND SOUTH CENTRAL KENT COUNTIES...

At 735 PM EDT, severe thunderstorms were located along a line
extending from near Andrewsville to near Bridgeville to Seaford,
moving east at 45 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...
Georgetown, Milford, Seaford, Lewes, Milton, Bridgeville, Ellendale,
Andrewsville, Blades, Greenwood and Farmington.

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.

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware...and eastern Maryland.

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.

Frequent cloud to ground lightning is occurring with these storms.
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 3865 7571 3885 7572 3893 7527 3879 7513
      3868 7532 3862 7559
TIME...MOT...LOC 2335Z 277DEG 37KT 3882 7556 3874 7556 3866 7563 

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

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 2, 8:07 PM EDTSevere Thunderstorm WarningPHICecil53 min
Sep 2, 8:47 PM EDTSevere Thunderstorm WarningPHICaroline, Cecil, Kent, Queen Anne's, Talbot58 min
Sep 2, 10:08 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot67 min
Sep 3, 5:47 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot73 min
Sep 2, 10:35 PM EDTSpecial Weather StatementPHISussex55 min
Sep 3, 7:40 PM EDTSevere Thunderstorm WarningPHISussex65 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.