Alert archive / Delaware / Tornado Warnings in 2020

Tornado Warning 9, NWS Philadelphia/Mount Holly

August 4, 2020Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this tornado warning at Aug 4, 2020, 4:50 AM EDT for Sussex County, Delaware. It was in force for 25 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 4, 2020, 4:50 AM EDT (08:50 UTC)
Expired: Aug 4, 2020, 5:15 AM EDT
In force: 25 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 0.0 in

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 34 km from the middle of the area, began a volume at 08:53 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 watch it was issued in

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

Issued	Product	Office	Lasted
Aug 4, 2:26 AM EDT	Tornado Watch	SPC	9 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 8.8 hours before the alert went out and 84 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: 920 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 841 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 59 m²/s²
0-3 km storm-relative helicity: 75 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

As transmitted.

648 
WFUS51 KPHI 040850
TORPHI
DEC005-040915-
/O.NEW.KPHI.TO.W.0009.200804T0850Z-200804T0915Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Mount Holly NJ
450 AM EDT Tue Aug 4 2020

The National Weather Service in Mount Holly NJ has issued a

* Tornado Warning for...
  East central Sussex County in southern Delaware...

* Until 515 AM EDT.
    
* At 449 AM EDT, a severe thunderstorm capable of producing a tornado
  was located near Millville, or 15 miles east of Georgetown, moving
  north at 30 mph.

  HAZARD...Tornado.

  SOURCE...Radar indicated rotation.

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely.

* Locations impacted include...
  Henlopen Acres and Long Neck. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3859 7508 3858 7513 3873 7521 3875 7509
TIME...MOT...LOC 0849Z 171DEG 25KT 3860 7511 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

JEO

2 follow-up statements

229 
WWUS51 KPHI 040859
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
459 AM EDT Tue Aug 4 2020

DEC005-040915-
/O.CON.KPHI.TO.W.0009.000000T0000Z-200804T0915Z/
Sussex DE-
459 AM EDT Tue Aug 4 2020

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 515 AM EDT FOR EAST
CENTRAL SUSSEX COUNTY...
    
At 459 AM EDT, a severe thunderstorm capable of producing a tornado
was located near Henlopen Acres, or 14 miles east of Georgetown,
moving north at 30 mph.

HAZARD...Tornado.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely.

Locations impacted include...
Henlopen Acres.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Protecting yourself from immediate threats to life and safety shall
take priority.  Whenever possible, as long as it does not cause
greater harm, all COVID-19 protective action guidance should be
followed.

TAKE COVER NOW! Move to a basement or an interior room on the lowest
floor of a sturdy building. Avoid windows. If you are outdoors, in a
mobile home, or in a vehicle, move to the closest substantial shelter
and protect yourself from flying debris.

&&

LAT...LON 3864 7509 3863 7514 3873 7521 3875 7509
TIME...MOT...LOC 0859Z 171DEG 25KT 3867 7512 

TORNADO...RADAR INDICATED
HAIL...0.00IN

$$

JEO

306 
WWUS51 KPHI 040910
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
510 AM EDT Tue Aug 4 2020

DEC005-040920-
/O.EXP.KPHI.TO.W.0009.000000T0000Z-200804T0915Z/
Sussex DE-
510 AM EDT Tue Aug 4 2020

...THE TORNADO WARNING FOR EAST CENTRAL SUSSEX COUNTY WILL EXPIRE AT
515 AM EDT...
        
The storm which prompted the warning has moved out of the area.
Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until noon EDT for southern
Delaware.

LAT...LON 3864 7509 3863 7514 3873 7521 3875 7509
TIME...MOT...LOC 0910Z 171DEG 25KT 3866 7512 

$$

JEO

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 4, 5:17 AM EDT	Areal Flood Advisory	PHI	New Castle	4 hr
Aug 4, 7:28 AM EDT	Flash Flood Warning	PHI	New Castle	3 hr
Aug 4, 7:39 AM EDT	Tornado Warning	PHI	Sussex	36 min
Aug 4, 7:51 AM EDT	Tornado Warning	PHI	Sussex	24 min
Aug 4, 8:15 AM EDT	Tornado Warning	PHI	Kent	45 min
Aug 4, 8:18 AM EDT	Tornado Warning	PHI	Sussex	27 min
Aug 4, 8:27 AM EDT	Tornado Warning	PHI	Kent	33 min
Aug 4, 8:56 AM EDT	Tornado Warning	PHI	Kent, New Castle	34 min
Aug 4, 8:58 AM EDT	Flash Flood Warning	PHI	Kent, New Castle, Sussex	3 hr
Aug 4, 9:06 AM EDT	River Flood Warning	PHI	New Castle	11 hr
Aug 4, 9:23 AM EDT	Flash Flood Warning	PHI	New Castle	4 hr
Aug 4, 9:23 AM EDT	Tornado Warning Tornado observed	PHI	New Castle	22 min
Aug 4, 10:02 AM EDT	Flash Flood Warning	PHI	New Castle	4 hr
Aug 4, 10:38 AM EDT	River Flood Warning	PHI	New Castle	14 hr
Aug 4, 12:27 PM EDT	River Flood Warning	PHI	New Castle	10 hr
Aug 4, 12:48 PM EDT	River Flood Warning	PHI	New Castle	24 hr
Aug 4, 1:59 PM EDT	Areal Flood Warning	PHI	New Castle	9 hr

Nearby

Tornado Warnings in Delaware, 2020 Every tornado warning in 2020 Tornadoes in 2020

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.