Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 308, NWS Philadelphia/Mount Holly

September 23, 2021New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 23, 2021, 11:42 AM EDT for New Castle County, Delaware. It was in force for 33 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 23, 2021, 11:42 AM EDT (15:42 UTC)
Expired: Sep 23, 2021, 12:15 PM EDT
In force: 33 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

County New Castle County, DE

The radar

The Dover AFB radar (KDOX), 93 km from the middle of the area, began a volume at 15:44 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 3.7 hours before the alert went out and 174 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 517 m above ground
0-6 km bulk shear: 58 kt
0-1 km storm-relative helicity: -71 m²/s²
0-3 km storm-relative helicity: 88 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

As transmitted.

257 
WUUS51 KPHI 231542
SVRPHI
DEC003-231615-
/O.NEW.KPHI.SV.W.0308.210923T1542Z-210923T1615Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
1142 AM EDT Thu Sep 23 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northeastern New Castle County in northern Delaware...

* Until 1215 PM EDT.

* At 1142 AM EDT, a severe thunderstorm was located over Saint
  Georges, or 7 miles northeast of Middletown, moving north at 50
  mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Wilmington, Pennsville, Elsmere, New Castle, Delaware City,
  Newport, Saint Georges, Greenville, Stanton, Delaware Memorial
  Bridge, Wilmington Manor, Ashland, Bear, Hockessin, Bellefonte and
  Edgemoor.

This includes Interstate 95 in Delaware between mile markers 7 and
18.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3980 7566 3978 7547 3965 7553 3963 7556
      3960 7555 3947 7561 3948 7568
TIME...MOT...LOC 1542Z 192DEG 46KT 3953 7563 

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

$$

Iovino

1 follow-up statement

604 
WWUS51 KPHI 231556
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
1156 AM EDT Thu Sep 23 2021

DEC003-231615-
/O.CON.KPHI.SV.W.0308.000000T0000Z-210923T1615Z/
New Castle DE-
1156 AM EDT Thu Sep 23 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1215 PM EDT
FOR NORTHEASTERN NEW CASTLE COUNTY...

At 1156 AM EDT, a severe thunderstorm was located over Wilmington
Manor, or near Wilmington, moving north at 50 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Wilmington, Pennsville, Elsmere, New Castle, Delaware City, Newport,
Greenville, Stanton, Delaware Memorial Bridge, Wilmington Manor,
Ashland, Hockessin, Bear, Bellefonte and Edgemoor.

This includes Interstate 95 in Delaware between mile markers 7 and
18.
 
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 3980 7566 3978 7547 3965 7553 3963 7556
      3960 7555 3952 7559 3964 7567
TIME...MOT...LOC 1556Z 191DEG 45KT 3970 7559 

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 23, 11:11 AM EDT	Special Weather Statement	PHI	New Castle	64 min
Sep 23, 11:33 AM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Sep 23, 11:57 AM EDT	Flash Flood Warning	PHI	New Castle	3 hr
Sep 23, 12:12 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	48 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.