Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 291, NWS Philadelphia/Mount Holly

September 1, 2021Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 1, 2021, 6:03 PM EDT for Kent County, Sussex County, Delaware. It was in force for 42 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: Sep 1, 2021, 6:03 PM EDT (22:03 UTC)
Expired: Sep 1, 2021, 6:45 PM EDT
In force: 42 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

Counties Kent County, DE, Sussex County, DE

The radar

The Dover AFB radar (KDOX), 26 km from the middle of the area, began a volume at 22:01 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Sep 1, 12:40 PM EDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.1 hours before the alert went out and 125 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: 515 J/kg
Mixed-layer CIN: -76 J/kg
Mixed-layer LCL: 955 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 57 m²/s²
0-3 km storm-relative helicity: 89 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

376 
WUUS51 KPHI 012203
SVRPHI
DEC001-005-012245-
/O.NEW.KPHI.SV.W.0291.210901T2203Z-210901T2245Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
603 PM EDT Wed Sep 1 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northwestern Sussex County in southern Delaware...
  Central Kent County in central Delaware...

* Until 645 PM EDT.

* At 603 PM EDT, severe thunderstorms were located along a line
  extending from Rising Sun to near Harrington to near Seaford,
  moving northeast at 35 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Dover, Milford, Seaford, Harrington, Camden, Milton, Bridgeville,
  Ellendale, Bowers, Woodside, Viola, Rising Sun-Lebanon, Dover Base
  Housing, Dover Speedway, Rising Sun, Big Stone Beach, Wyoming,
  Felton, Blades and Greenwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

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

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

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

&&

LAT...LON 3934 7543 3925 7539 3909 7537 3885 7522
      3856 7564 3891 7558 3912 7558
TIME...MOT...LOC 2203Z 217DEG 32KT 3911 7552 3892 7550 3867 7555 

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

$$

Staarmann

1 follow-up statement

994 
WWUS51 KPHI 012220
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
620 PM EDT Wed Sep 1 2021

DEC001-005-012245-
/O.CON.KPHI.SV.W.0291.000000T0000Z-210901T2245Z/
Sussex DE-Kent DE-
620 PM EDT Wed Sep 1 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR NORTHWESTERN SUSSEX AND EASTERN KENT COUNTIES...

At 620 PM EDT, severe thunderstorms were located along a line
extending from 6 miles northeast of Dover Speedway to near Bowers to
near Ellendale, moving northeast at 35 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Dover, Milford, Seaford, Milton, Bridgeville, Ellendale, Bowers,
Dover Base Housing, Big Stone Beach, Rising Sun-Lebanon, Blades,
Frederica, Magnolia, Little Creek and Bethel.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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.

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

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

&&

LAT...LON 3856 7564 3875 7561 3887 7550 3903 7548
      3922 7549 3930 7541 3925 7539 3909 7537
      3885 7522
TIME...MOT...LOC 2220Z 216DEG 32KT 3922 7541 3903 7539 3876 7547 

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

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 1, 6:19 AM EDT	Areal Flood Advisory	PHI	New Castle	116 min
Sep 1, 6:49 AM EDT	Flash Flood Warning	PHI	New Castle	86 min
Sep 1, 8:03 AM EDT	River Flood Warning	PHI	New Castle	4 hr
Sep 1, 2:53 PM EDT	Flash Flood Warning	PHI	New Castle	9 hr
Sep 1, 4:59 PM EDT	Tornado Warning	PHI	Kent, Sussex	46 min
Sep 1, 5:01 PM EDT	Tornado Warning	PHI	Kent, New Castle	44 min
Sep 1, 5:16 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	44 min
Sep 1, 5:26 PM EDT	Flash Flood Warning	PHI	New Castle	9 hr
Sep 1, 5:35 PM EDT	Tornado Warning	PHI	Kent, New Castle	25 min
Sep 1, 6:08 PM EDT	River Flood Warning	PHI	New Castle	18 hr
Sep 1, 6:15 PM EDT	River Flood Warning	PHI	New Castle	9 hr
Sep 1, 6:24 PM EDT	Tornado Warning	PHI	New Castle	16 min
Sep 1, 6:38 PM EDT	River Flood Warning	PHI	New Castle	28 hr
Sep 1, 6:57 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	63 min
Sep 1, 7:44 PM EDT	River Flood Warning	PHI	New Castle	11 hr

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.