Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 102, NWS Philadelphia/Mount Holly

June 21, 2021Kent County, New Castle County, Sussex County, Delaware; Cumberland County, Salem County, New Jersey; Caroline County, Kent County, Queen Anne's County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 21, 2021, 7:43 PM EDT for Kent County, New Castle County, Sussex County, Delaware; Cumberland County, Salem County, New Jersey; Caroline County, Kent County, Queen Anne's County, Maryland. 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
Jun 21, 2021, 7:43 PM EDT (23:43 UTC)
Expired
Jun 21, 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, New Castle County, DE, Sussex County, DE, Caroline County, MD, Kent County, MD, Queen Anne's County, MD, Cumberland County, NJ, Salem County, NJ

The radar

The Dover AFB radar (KDOX), 30 km from the middle of the area, began a volume at 23:43 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
Jun 21, 7:45 PM EDTTSTM WND DMG2 Se Delaney Corner, DEDOWNED TREE ON WIRES NEAR LONGRIDGE ROAD. 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
Jun 21, 4:33 PM EDTSevere Thunderstorm WatchSPC6 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.7 hours before the alert went out and 129 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 2021-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 525 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 2021-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 4 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
525 J/kg
Mixed-layer CIN
-38 J/kg
Mixed-layer LCL
630 m above ground
0-6 km bulk shear
7 kt
0-1 km storm-relative helicity
4 m²/s²
0-3 km storm-relative helicity
-14 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

762 
WUUS51 KPHI 212343
SVRPHI
DEC001-003-005-MDC011-029-035-NJC011-033-220030-
/O.NEW.KPHI.SV.W.0102.210621T2343Z-210622T0030Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
743 PM EDT Mon Jun 21 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern Sussex County in southern Delaware...
  South central New Castle County in northern Delaware...
  Kent County in central Delaware...
  Eastern Queen Anne's County in northeastern Maryland...
  Northeastern Caroline County in eastern Maryland...
  East central Kent County in northeastern Maryland...
  Southwestern Cumberland County in southern New Jersey...
  Southwestern Salem County in southern New Jersey...

* Until 830 PM EDT.

* At 743 PM EDT, a cluser of severe thunderstorms were located over 
  Sudlersville, or 16 miles west of Dover, moving east at 40 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Dover, Centerville, Smyrna, Milford, Denton, Centreville,
  Harrington, Camden, Clayton, Lewes, Greensboro, Oakland, Ridgely,
  Cheswold, Greenwich, Sudlersville, Ellendale, Bowers, Goldsboro and
  Woodside.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3904 7607 3949 7555 3935 7508 3924 7496
      3879 7512 3879 7546 3893 7595
TIME...MOT...LOC 2343Z 269DEG 41KT 3918 7582 

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

NC
2 follow-up statements
844 
WWUS51 KPHI 220015
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
815 PM EDT Mon Jun 21 2021

DEC003-NJC033-220024-
/O.CAN.KPHI.SV.W.0102.000000T0000Z-210622T0030Z/
New Castle DE-Salem NJ-
815 PM EDT Mon Jun 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL NEW CASTLE AND
SOUTHWESTERN SALEM 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 midnight EDT for
central, northern and southern Delaware...eastern and northeastern
Maryland...and southern New Jersey.

LAT...LON 3893 7595 3898 7594 3910 7584 3915 7575
      3925 7576 3925 7582 3930 7577 3929 7565
      3931 7558 3935 7555 3935 7508 3924 7496
      3879 7512 3879 7546
TIME...MOT...LOC 0014Z 269DEG 41KT 3919 7536 

$$

DEC001-005-MDC011-029-035-NJC011-220030-
/O.CON.KPHI.SV.W.0102.000000T0000Z-210622T0030Z/
Sussex DE-Kent DE-Queen Anne's MD-Caroline MD-Kent MD-Cumberland NJ-
815 PM EDT Mon Jun 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 830 PM EDT
FOR NORTHERN SUSSEX...KENT...SOUTHEASTERN QUEEN ANNE'S...NORTHEASTERN
CAROLINE...EASTERN KENT AND SOUTHWESTERN CUMBERLAND COUNTIES...

At 814 PM EDT, a cluser of severe thunderstorms were located 8 miles 
northeast of Dover Base Housing, or 8 miles east of Dover, moving 
east at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Dover, Smyrna, Milford, Denton, Harrington, Camden, Clayton, Lewes,
Greensboro, Oakland, Ridgely, Cheswold, Ellendale, Bowers, Goldsboro,
Woodside, Viola, Hartly, Hazlettville and Dover Speedway.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3893 7595 3898 7594 3910 7584 3915 7575
      3925 7576 3925 7582 3930 7577 3929 7565
      3931 7558 3935 7555 3935 7508 3924 7496
      3879 7512 3879 7546
TIME...MOT...LOC 0014Z 269DEG 41KT 3919 7536 

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

NC
609 
WWUS51 KPHI 220023
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
823 PM EDT Mon Jun 21 2021

DEC001-005-MDC011-029-035-NJC011-220033-
/O.EXP.KPHI.SV.W.0102.000000T0000Z-210622T0030Z/
Sussex DE-Kent DE-Queen Anne's MD-Caroline MD-Kent MD-Cumberland NJ-
823 PM EDT Mon Jun 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHERN SUSSEX...KENT...
SOUTHEASTERN QUEEN ANNE'S...NORTHEASTERN CAROLINE...EASTERN KENT AND
SOUTHWESTERN CUMBERLAND COUNTIES WILL EXPIRE AT 830 PM EDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds are still possible with
this thunderstorm.

A Severe Thunderstorm Watch remains in effect until midnight EDT for
central, northern and southern Delaware...eastern and northeastern
Maryland...and southern New Jersey.

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 3893 7595 3898 7594 3910 7584 3915 7575
      3925 7576 3925 7582 3930 7577 3929 7565
      3931 7558 3935 7555 3935 7508 3924 7496
      3879 7512 3879 7546
TIME...MOT...LOC 0023Z 269DEG 41KT 3919 7535 

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 21, 4:35 AM EDTHeat AdvisoryPHINew Castle15 hr
Jun 21, 6:21 PM EDTSevere Thunderstorm WarningPHINew Castle54 min
Jun 21, 6:47 PM EDTSevere Thunderstorm WarningPHIKent, New Castle58 min
Jun 21, 7:12 PM EDTSevere Thunderstorm WarningPHINew Castle48 min
Jun 21, 7:24 PM EDTSpecial Marine WarningPHI66 min
Jun 21, 7:38 PM EDTSevere Thunderstorm WarningPHIWarren52 min
Jun 21, 7:55 PM EDTSpecial Weather StatementPHIAtlantic, Burlington, Camden, Mercer, Ocean50 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2021Severe Thunderstorm Warnings in Maryland, 2021Severe Thunderstorm Warnings in New Jersey, 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.