Alert archive / Delaware / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 58, NWS Philadelphia/Mount Holly

June 19, 2017Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 19, 2017, 8:24 PM EDT for Kent County, Sussex County, Delaware. It was in force for 36 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 19, 2017, 8:24 PM EDT (00:24 UTC)
Expired
Jun 19, 2017, 9:00 PM EDT
In force
36 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Kent County, DE, Sussex County, DE

The radar

The Dover AFB radar (KDOX), 13 km from the middle of the area, began a volume at 00:24 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 00:00Z, 0.4 hours before the alert went out and 92 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 00:00Z on 2017-06-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1394 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 00:00Z on 2017-06-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 162 square meters per square second.193958Sfc1 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
1394 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
1009 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
162 m²/s²
0-3 km storm-relative helicity
157 m²/s²
Significant tornado parameter
1.2
Supercell composite
8.5

Open this sounding in Storm Lab

The text

As transmitted.

671 
WUUS51 KPHI 200024
SVRPHI
DEC001-005-200100-
/O.NEW.KPHI.SV.W.0058.170620T0024Z-170620T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
824 PM EDT MON JUN 19 2017

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Western Sussex County in southern Delaware...
  South central Kent County in central Delaware...

* Until 900 PM EDT

* At 823 PM EDT, severe thunderstorms were located along a line
  extending from near Hurlock to Sharptown, moving northeast at 55
  mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

  IMPACT...Expect damage to trees and power lines. 

* Severe thunderstorms will be near,
  Seaford and Laurel around 835 PM EDT. 
  Bridgeville around 840 PM EDT. 
  Georgetown around 845 PM EDT. 
  Ellendale around 850 PM EDT. 
  Milton around 855 PM EDT. 

Other locations impacted by these severe thunderstorms include
Bethel, Farmington, Blades and Greenwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and 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.

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

&&

LAT...LON 3877 7572 3890 7556 3886 7538 3875 7529
      3846 7569
TIME...MOT...LOC 0023Z 229DEG 50KT 3860 7589 3857 7579 3853 7575 

HAIL...<.75IN
WIND...60MPH
 
$$
Drag
2 follow-up statements
489 
WWUS51 KPHI 200043
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
843 PM EDT MON JUN 19 2017

DEC001-005-200100-
/O.CON.KPHI.SV.W.0058.000000T0000Z-170620T0100Z/
Sussex DE-Kent DE-
843 PM EDT MON JUN 19 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR NORTHWESTERN SUSSEX AND SOUTH CENTRAL KENT COUNTIES...

At 842 PM EDT, severe thunderstorms were located along a line
extending from near Smithville to near Bridgeville to near Seaford,
moving northeast at 50 mph.

HAZARD...60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...Expect damage to trees and power lines. 

These severe storms will be near...
  Georgetown around 850 PM EDT. 
  Ellendale around 855 PM EDT. 
  Milton around 900 PM EDT. 

Other locations impacted by these severe thunderstorms include
Bethel, Farmington, Blades and Greenwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and 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.

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

&&

LAT...LON 3877 7572 3890 7556 3886 7538 3875 7529
      3852 7569
TIME...MOT...LOC 0042Z 226DEG 44KT 3879 7565 3873 7555 3871 7556 

HAIL...<.75IN
WIND...60MPH
 
$$

Drag
551 
WWUS51 KPHI 200053
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
853 PM EDT MON JUN 19 2017

DEC001-005-200102-
/O.EXP.KPHI.SV.W.0058.000000T0000Z-170620T0100Z/
Sussex DE-Kent DE-
853 PM EDT MON JUN 19 2017

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN SUSSEX AND SOUTH
CENTRAL KENT COUNTIES WILL EXPIRE AT 900 PM EDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore the warning will be allowed to expire.

LAT...LON 3877 7572 3890 7556 3886 7538 3875 7529
      3852 7569
TIME...MOT...LOC 0052Z 229DEG 50KT 3887 7553 3881 7543 3879 7544 

$$

Drag

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 19, 8:12 PM EDTSpecial Weather StatementPHISussex48 min
Jun 19, 8:20 PM EDTFlash Flood WarningPHISussex3 hr
Jun 19, 8:32 PM EDTAreal Flood AdvisoryPHIKent, Sussex3 hr
Jun 19, 8:45 PM EDTSpecial Weather StatementPHISussex30 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2017Every severe thunderstorm warning in 2017

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.