Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 285, NWS Philadelphia/Mount Holly

August 30, 2021Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 30, 2021, 6:02 PM EDT for Kent County, Sussex County, Delaware. It was in force for 28 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 30, 2021, 6:02 PM EDT (22:02 UTC)
Expired: Aug 30, 2021, 6:30 PM EDT
In force: 28 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

The radar

The Dover AFB radar (KDOX), 19 km from the middle of the area, began a volume at 22:02 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, 10.0 hours before the alert went out and 117 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 392 J/kg
Mixed-layer CIN: -89 J/kg
Mixed-layer LCL: 791 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: -19 m²/s²
0-3 km storm-relative helicity: -9 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

606 
WUUS51 KPHI 302202
SVRPHI
DEC001-005-302245-
/O.NEW.KPHI.SV.W.0285.210830T2202Z-210830T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
602 PM EDT Mon Aug 30 2021

The National Weather Service in Mount Holly NJ has issued a

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

* Until 645 PM EDT.

* At 602 PM EDT, a severe thunderstorm was located near Viola, or 12
  miles south of Dover, moving southeast at 15 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Milford, Harrington, Woodside, Viola, Big Stone Beach, Felton,
  Frederica, Houston, Woodside East and Riverview.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to 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 3901 7569 3909 7556 3899 7530 3879 7548
TIME...MOT...LOC 2202Z 297DEG 13KT 3899 7558 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse

2 follow-up statements

749 
WWUS51 KPHI 302211
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
611 PM EDT Mon Aug 30 2021

DEC001-005-302245-
/O.CON.KPHI.SV.W.0285.000000T0000Z-210830T2245Z/
Sussex DE-Kent DE-
611 PM EDT Mon Aug 30 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR NORTH CENTRAL SUSSEX AND SOUTHERN KENT COUNTIES...

At 611 PM EDT, a severe thunderstorm was located near Harrington, or
12 miles south of Dover, moving southeast at 15 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Milford, Harrington, Viola, Felton, Frederica, Houston, Riverview and
Woodside East.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 3901 7569 3907 7552 3899 7530 3879 7548
TIME...MOT...LOC 2211Z 294DEG 14KT 3898 7553 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Gorse

968 
WWUS51 KPHI 302230
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
630 PM EDT Mon Aug 30 2021

DEC001-005-302240-
/O.CAN.KPHI.SV.W.0285.000000T0000Z-210830T2245Z/
Sussex DE-Kent DE-
630 PM EDT Mon Aug 30 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SUSSEX AND
SOUTHERN KENT COUNTIES IS CANCELLED...
                
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 has been cancelled.  However gusty winds and
heavy rain are still possible with this thunderstorm.

LAT...LON 3901 7569 3907 7552 3899 7530 3879 7548
TIME...MOT...LOC 2229Z 297DEG 13KT 3895 7545 

$$

Gorse

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 5:00 AM EDT	Flash Flood Watch	PHI	Kent, New Castle, Sussex	71 hr
Aug 30, 3:44 PM EDT	Special Weather Statement	PHI	New Castle	31 min
Aug 30, 4:14 PM EDT	Special Weather Statement	PHI	Kent	31 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2021 Every 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.