Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 264, NWS Philadelphia/Mount Holly

August 13, 2021Caroline County, Maryland; Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 13, 2021, 7:43 PM EDT for Caroline County, Maryland; Kent County, Sussex County, Delaware. It was in force for 47 min. 1 report 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 13, 2021, 7:43 PM EDT (23:43 UTC)
Expired
Aug 13, 2021, 8:30 PM EDT
In force
47 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

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

The radar

The Dover AFB radar (KDOX), 18 km from the middle of the area, began a volume at 23:45 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 13, 8:06 PM EDTTSTM WND DMGGreenwood, DETREES DOWN IN GREENWOOD, 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 13, 1:11 PM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.7 hours before the alert went out and 113 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 2021-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 809 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 2021-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 55 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
809 J/kg
Mixed-layer CIN
-190 J/kg
Mixed-layer LCL
1510 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
55 m²/s²
0-3 km storm-relative helicity
32 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

006 
WUUS51 KPHI 132343
SVRPHI
DEC001-005-MDC011-140030-
/O.NEW.KPHI.SV.W.0264.210813T2343Z-210814T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
743 PM EDT Fri Aug 13 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 830 PM EDT.

* At 743 PM EDT, a cluster of severe thunderstorms were located over 
  Andrewsville, or 17 miles northwest of Georgetown, moving east at 
  25 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...
  Dover, Milford, Denton, Harrington, Camden, Greensboro, Ellendale,
  Bowers, Woodside, Viola, Rising Sun-Lebanon, Dover Base Housing,
  Sandtown, Andrewsville, Rising Sun, Big Stone Beach, Wyoming,
  Felton, Greenwood and Frederica.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3877 7585 3888 7589 3907 7574 3916 7552
      3909 7519 3882 7512
TIME...MOT...LOC 2343Z 257DEG 21KT 3888 7561 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

NC
2 follow-up statements
634 
WWUS51 KPHI 140006
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
806 PM EDT Fri Aug 13 2021

MDC011-140015-
/O.CAN.KPHI.SV.W.0264.000000T0000Z-210814T0030Z/
Caroline MD-
806 PM EDT Fri Aug 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CAROLINE COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3878 7572 3892 7573 3903 7567 3916 7552
      3909 7519 3882 7512
TIME...MOT...LOC 0005Z 257DEG 21KT 3891 7544 

$$

DEC001-005-140030-
/O.CON.KPHI.SV.W.0264.000000T0000Z-210814T0030Z/
Sussex DE-Kent DE-
806 PM EDT Fri Aug 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTHERN SUSSEX AND SOUTHERN KENT COUNTIES...

At 805 PM EDT, a severe thunderstorm was located over Milford, or 15
miles north of Georgetown, moving east at 25 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...
Dover, Milford, Harrington, Camden, Ellendale, Bowers, Woodside,
Viola, Rising Sun-Lebanon, Dover Base Housing, Andrewsville, Rising
Sun, Big Stone Beach, Wyoming, Felton, Greenwood, Frederica, Houston,
Magnolia and Farmington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

&&

LAT...LON 3878 7572 3892 7573 3903 7567 3916 7552
      3909 7519 3882 7512
TIME...MOT...LOC 0005Z 257DEG 21KT 3891 7544 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

NC
346 
WWUS51 KPHI 140025
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
825 PM EDT Fri Aug 13 2021

DEC001-005-140035-
/O.EXP.KPHI.SV.W.0264.000000T0000Z-210814T0030Z/
Sussex DE-Kent DE-
825 PM EDT Fri Aug 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN SUSSEX AND SOUTHERN
KENT COUNTIES WILL EXPIRE AT 830 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds are still possible with this thunderstorm.

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 3878 7572 3892 7573 3903 7567 3916 7552
      3909 7519 3882 7512
TIME...MOT...LOC 0025Z 257DEG 21KT 3893 7531 

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 6:02 PM EDTSpecial Weather StatementPHIKent, Queen Anne's58 min
Aug 13, 6:29 PM EDTSpecial Weather StatementPHICaroline31 min
Aug 13, 6:29 PM EDTSevere Thunderstorm WarningPHIQueen Anne's, Talbot25 min
Aug 13, 6:45 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's30 min
Aug 13, 7:12 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's33 min
Aug 13, 7:57 PM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's, Talbot93 min
Aug 13, 3:21 PM EDTSpecial Weather StatementPHISussex24 min
Aug 13, 6:04 PM EDTSpecial Weather StatementPHISussex26 min
Aug 13, 6:47 PM EDTSpecial Weather StatementPHISussex43 min
Aug 13, 6:53 PM EDTSevere Thunderstorm WarningPHISussex37 min
Aug 13, 7:30 PM EDTSpecial Weather StatementPHISussex45 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2021Severe Thunderstorm Warnings in Maryland, 2021Every 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.