Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 262, NWS Philadelphia/Mount Holly

August 13, 2021Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 13, 2021, 6:53 PM EDT for Sussex County, Delaware. It was in force for 37 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 13, 2021, 6:53 PM EDT (22:53 UTC)
Expired
Aug 13, 2021, 7:30 PM EDT
In force
37 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 20 km from the middle of the area, began a volume at 22:53 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.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.9 hours before the alert went out and 80 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.

393 
WUUS51 KPHI 132253
SVRPHI
DEC005-132330-
/O.NEW.KPHI.SV.W.0262.210813T2253Z-210813T2330Z/

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

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Southern Sussex County in southern Delaware...

* Until 730 PM EDT.

* At 653 PM EDT, a severe thunderstorm was located near Sycamore, or
  near Georgetown, moving southeast at 10 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...
  Georgetown, Seaford, Millsboro, Laurel, Bridgeville, Sycamore,
  Blades, Greenwood and Bethel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3855 7560 3870 7572 3882 7559 3879 7541
      3871 7520 3857 7529 3848 7544
TIME...MOT...LOC 2253Z 301DEG 8KT 3867 7550 

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

$$

NC
2 follow-up statements
116 
WWUS51 KPHI 132312
SVSPHI

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

DEC005-132330-
/O.CON.KPHI.SV.W.0262.000000T0000Z-210813T2330Z/
Sussex DE-
712 PM EDT Fri Aug 13 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 730 PM EDT
FOR CENTRAL SUSSEX COUNTY...

At 711 PM EDT, a severe thunderstorm was located near Sycamore, or
near Georgetown, moving southeast at 10 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...
Georgetown, Seaford, Millsboro, Bridgeville, Sycamore, Blades and
Greenwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3857 7554 3868 7566 3881 7559 3879 7541
      3871 7520 3857 7530 3853 7541
TIME...MOT...LOC 2311Z 301DEG 8KT 3865 7546 

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

$$

PO
366 
WWUS51 KPHI 132327
SVSPHI

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

DEC005-132337-
/O.EXP.KPHI.SV.W.0262.000000T0000Z-210813T2330Z/
Sussex DE-
727 PM EDT Fri Aug 13 2021

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL SUSSEX COUNTY WILL
EXPIRE AT 730 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 and heavy rain 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 3857 7554 3868 7566 3881 7559 3879 7541
      3871 7520 3857 7530 3853 7541
TIME...MOT...LOC 2327Z 301DEG 8KT 3905 7572 

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 13, 3:21 PM EDTSpecial Weather StatementPHISussex24 min
Aug 13, 6:04 PM EDTSpecial Weather StatementPHISussex26 min
Aug 13, 6:45 PM EDTSevere Thunderstorm WarningPHIKent30 min
Aug 13, 6:47 PM EDTSpecial Weather StatementPHISussex43 min
Aug 13, 7:12 PM EDTSevere Thunderstorm WarningPHIKent, Sussex33 min
Aug 13, 7:30 PM EDTSpecial Weather StatementPHISussex45 min
Aug 13, 7:43 PM EDTSevere Thunderstorm WarningPHIKent, Sussex47 min
Aug 13, 7:57 PM EDTAreal Flood AdvisoryPHIKent, Sussex93 min

Nearby

Severe Thunderstorm Warnings in Delaware, 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.