Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 70, NWS Philadelphia/Mount Holly

June 9, 2021Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 9, 2021, 2:28 PM EDT for Sussex County, Delaware. It was in force for 62 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
Jun 9, 2021, 2:28 PM EDT (18:28 UTC)
Expired
Jun 9, 2021, 3:30 PM EDT
In force
62 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 23 km from the middle of the area, began a volume at 18:28 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, 6.5 hours before the alert went out and 90 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 12:00Z on 2021-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 795 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Wallops Is Stn, VA at 12:00Z on 2021-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
795 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
967 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

187 
WUUS51 KPHI 091828
SVRPHI
DEC005-091930-
/O.NEW.KPHI.SV.W.0070.210609T1828Z-210609T1930Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
228 PM EDT Wed Jun 9 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northeastern Sussex County in southern Delaware...

* Until 330 PM EDT.

* At 228 PM EDT, a severe thunderstorm was located near Milton, or 9
  miles northeast of Georgetown, and is nearly stationary.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Lewes and Milton. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition 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 3863 7517 3874 7538 3888 7526 3875 7509
TIME...MOT...LOC 1828Z 214DEG 3KT 3877 7525 

HAIL...0.75IN
WIND...60MPH
 
$$

Gorse
2 follow-up statements
180 
WWUS51 KPHI 091846
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
246 PM EDT Wed Jun 9 2021

DEC005-091930-
/O.CON.KPHI.SV.W.0070.000000T0000Z-210609T1930Z/
Sussex DE-
246 PM EDT Wed Jun 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 330 PM EDT
FOR EAST CENTRAL SUSSEX COUNTY...

At 245 PM EDT, a severe thunderstorm was located near Lewes, or 11
miles east of Georgetown, moving east at 5 mph.

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

SOURCE...Radar indicated.

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

Locations impacted include...
Lewes and Milton. 

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. For your safety, immediately move off the beach and 
seek shelter indoors.

&&

LAT...LON 3874 7538 3884 7521 3875 7509 3863 7517
TIME...MOT...LOC 1845Z 287DEG 5KT 3874 7518 

HAIL...0.75IN
WIND...60MPH
 
$$

Gorse
214 
WWUS51 KPHI 091923
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
323 PM EDT Wed Jun 9 2021

DEC005-091932-
/O.EXP.KPHI.SV.W.0070.000000T0000Z-210609T1930Z/
Sussex DE-
323 PM EDT Wed Jun 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL SUSSEX COUNTY
WILL EXPIRE AT 330 PM EDT...
        
The storm which prompted the warning is moving out of the area.
Therefore, this warning will be allowed to expire. Another warning 
continues just to the south.

LAT...LON 3874 7538 3884 7521 3875 7509 3863 7517
TIME...MOT...LOC 1922Z 214DEG 3KT 3877 7516 

$$

Gorse

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 8, 8:15 PM EDTSpecial Weather StatementPHISussex45 min
Jun 9, 7:54 AM EDTRiver Flood WarningPHINew Castle5 hr
Jun 9, 1:35 PM EDTSpecial Weather StatementPHINew Castle25 min
Jun 9, 2:07 PM EDTSevere Thunderstorm WarningPHINew Castle23 min
Jun 9, 2:21 PM EDTFlash Flood WarningPHINew Castle73 min
Jun 9, 2:26 PM EDTSevere Thunderstorm WarningPHIKent64 min
Jun 9, 3:11 PM EDTSevere Thunderstorm WarningPHISussex64 min
Jun 9, 3:24 PM EDTAreal Flood AdvisoryPHISussex3 hr
Jun 9, 4:32 PM EDTAreal Flood AdvisoryPHISussex108 min
Jun 9, 4:37 PM EDTSevere Thunderstorm WarningPHIKent, Sussex27 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2021Every 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.