Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 229, NWS Philadelphia/Mount Holly

July 29, 2021Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 29, 2021, 2:43 PM EDT for Sussex County, Delaware. It was in force for 62 min. 3 reports 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: Jul 29, 2021, 2:43 PM EDT (18:43 UTC)
Expired: Jul 29, 2021, 3:45 PM EDT
In force: 62 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 22 km from the middle of the area, began a volume at 18:42 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

Time	Report	Where	Remark
Jul 29, 2:48 PM EDT	TSTM WND DMG	4 Se Harbeson, DE	A SUPERCELL THUNDERSTORM IMPACTED THE EASTERN PORTIONS OF SUSSEX COUNTY, DE IN THE EARLY AFTERNOON HOURS OF JULY 29. THE NATIONAL WEATHER SERVICE INVESTIGATED REPORTS OF DAMAGE IN THIS AREA. A SURVEY WAS CONDUCTED ALONG A PATH OF RADAR-INDICATED ROTATION FROM
Jul 29, 2:48 PM EDT	TSTM WND DMG	4 Se Harbeson, DE	TREES DOWN NEAR HOLLYMOUNT, DE.
Jul 29, 2:59 PM EDT	HAIL 1	3 Nw Long Neck, DE	ONE INCH HAIL REPORTED NORTH OF LONG NECK, DE.

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.

Issued	Product	Office	Lasted
Jul 29, 2:23 PM EDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 6.7 hours before the alert went out and 87 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: 581 J/kg
Mixed-layer CIN: -61 J/kg
Mixed-layer LCL: 863 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 44 m²/s²
0-3 km storm-relative helicity: 112 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted.

851 
WUUS51 KPHI 291843
SVRPHI
DEC005-291945-
/O.NEW.KPHI.SV.W.0229.210729T1843Z-210729T1945Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
243 PM EDT Thu Jul 29 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  East central Sussex County in southern Delaware...

* Until 345 PM EDT.

* At 243 PM EDT, a severe thunderstorm was located near Milton, or
  near Georgetown, moving east at 15 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Minor damage to vehicles is possible. Wind damage to 
           roofs, siding, trees, and power lines is possible.

* Locations impacted include...
  Lewes, Henlopen Acres, Cape Henlopen State Park, Long Neck and
  Dewey Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for southern
Delaware.

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, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

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

&&

LAT...LON 3865 7536 3875 7536 3883 7508 3861 7505
TIME...MOT...LOC 1843Z 263DEG 11KT 3870 7529 

HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

6 follow-up statements

015 
WWUS51 KPHI 291852
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
252 PM EDT Thu Jul 29 2021

DEC005-291945-
/O.CON.KPHI.SV.W.0229.000000T0000Z-210729T1945Z/
Sussex DE-
252 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR EAST CENTRAL SUSSEX COUNTY...

At 252 PM EDT, a severe thunderstorm was located near Milton, or 7
miles east of Georgetown, moving east at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Lewes, Henlopen Acres, Cape Henlopen State Park, Long Neck and Dewey
Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for 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.

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 3865 7534 3873 7532 3883 7508 3861 7505
TIME...MOT...LOC 1852Z 266DEG 11KT 3869 7525 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

887 
WWUS51 KPHI 291905
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
305 PM EDT Thu Jul 29 2021

DEC005-291945-
/O.CON.KPHI.SV.W.0229.000000T0000Z-210729T1945Z/
Sussex DE-
305 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR EAST CENTRAL SUSSEX COUNTY...

At 304 PM EDT, a severe thunderstorm was located near Henlopen 
Acres, or 11 miles east of Georgetown, moving east at 15 mph. 
Additionally, a Tornado Warning remains in effect for portions of 
Sussex County.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Henlopen Acres, Long Neck and Dewey Beach. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for 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.

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 3864 7525 3864 7527 3873 7525 3877 7507
      3872 7507 3861 7505
TIME...MOT...LOC 1904Z 268DEG 12KT 3868 7518 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

376 
WWUS51 KPHI 291915
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
315 PM EDT Thu Jul 29 2021

DEC005-291945-
/O.CON.KPHI.SV.W.0229.000000T0000Z-210729T1945Z/
Sussex DE-
315 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR EAST CENTRAL SUSSEX COUNTY...

At 314 PM EDT, a severe thunderstorm was located near Henlopen 
Acres, or 14 miles east of Georgetown, moving east at 20 mph. 
Additionally, a Tornado Warning remains in effect for portions of 
Sussex County.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Henlopen Acres, Long Neck and Dewey Beach. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for 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.

Prepare immediately for large hail and damaging winds. People outside
should seek shelter inside a well-built structure and away from
windows.

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 3863 7520 3864 7522 3871 7522 3874 7507
      3861 7505
TIME...MOT...LOC 1914Z 290DEG 15KT 3864 7513 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

571 
WWUS51 KPHI 291924
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
324 PM EDT Thu Jul 29 2021

DEC005-291945-
/O.CON.KPHI.SV.W.0229.000000T0000Z-210729T1945Z/
Sussex DE-
324 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR EASTERN SUSSEX COUNTY...

At 324 PM EDT, a severe thunderstorm was located near Millville, or 
17 miles east of Georgetown, moving east at 15 mph. Additionally, a 
Tornado Warning remains in effect for portions of Sussex County.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Long Neck and Dewey Beach. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for 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.

Prepare immediately for large hail and damaging winds. People outside
should seek shelter inside a well-built structure and away from
windows.

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 3863 7520 3869 7516 3871 7507 3871 7506
      3867 7506 3861 7505
TIME...MOT...LOC 1924Z 291DEG 14KT 3863 7508 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

896 
WWUS51 KPHI 291933
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
333 PM EDT Thu Jul 29 2021

DEC005-291945-
/O.CON.KPHI.SV.W.0229.000000T0000Z-210729T1945Z/
Sussex DE-
333 PM EDT Thu Jul 29 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR EAST CENTRAL SUSSEX COUNTY...

At 333 PM EDT, a severe thunderstorm was located near Millville, or
17 miles north of Ocean City, moving southeast at 15 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Trained weather spotters.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Long Neck.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM EDT for 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.

Frequent cloud to ground lightning is occurring with this storm, and
the storm will affect the beaches. For your safety, immediately move
off the beach and seek shelter indoors.

&&

LAT...LON 3862 7507 3862 7514 3865 7512 3867 7506
      3861 7505
TIME...MOT...LOC 1933Z 293DEG 13KT 3861 7506 

TORNADO...POSSIBLE
HAIL...1.00IN
WIND...60MPH
 
$$

Staarmann

973 
WWUS51 KPHI 291943
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
343 PM EDT Thu Jul 29 2021

DEC005-291952-
/O.EXP.KPHI.SV.W.0229.000000T0000Z-210729T1945Z/
Sussex DE-
343 PM EDT Thu Jul 29 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL SUSSEX COUNTY
WILL EXPIRE AT 345 PM EDT...
        
The storm which prompted the warning has moved offshore and out of 
the area. Therefore, the warning will be allowed to expire.

A Tornado Watch remains in effect until 900 PM EDT for southern
Delaware.

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 3862 7507 3862 7514 3865 7512 3867 7506
      3861 7505
TIME...MOT...LOC 1942Z 263DEG 11KT 3861 7503 

$$

Staarmann

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 1:37 PM EDT	Special Weather Statement	PHI	Sussex	38 min
Jul 29, 2:38 PM EDT	Special Weather Statement	PHI	Sussex	37 min
Jul 29, 3:02 PM EDT	Tornado Warning	PHI	Sussex	43 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.