Alert archive / Delaware / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 307, NWS Philadelphia/Mount Holly

August 1, 2019Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 1, 2019, 5:28 PM EDT for Sussex County, Delaware. It was in force for 47 min. 9 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: Aug 1, 2019, 5:28 PM EDT (21:28 UTC)
Expired: Aug 1, 2019, 6:15 PM EDT
In force: 47 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), 32 km from the middle of the area, began a volume at 21:30 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
Aug 1, 5:41 PM EDT	HAIL 0.75	Seaford, DE	HAIL UP TO PENNY SIZE REPORTED NEAR SEAFORD.
Aug 1, 5:44 PM EDT	HAIL 1	Seaford, DE	QUARTER SIZE HAIL REPORTED IN SEAFORD.
Aug 1, 5:45 PM EDT	TSTM WND DMG	1 S Seaford, DE	TREE DOWN ONTO POWER LINES IN BLADES. TIME ESTIMATED FROM RADAR.
Aug 1, 5:50 PM EDT	TSTM WND DMG	Laurel, DE	SECTION OF A TREE SNAPPED OFF AND FELL ONTO POWER LINES. A LARGE TREE WAS ALSO UPROOTED. TIME ESTIMATED FROM RADAR.
Aug 1, 5:53 PM EDT	TSTM WND DMG	Laurel, DE	TREE AND LARGE LIMBS REPORTED DOWN NEAR LAUREL.
Aug 1, 5:53 PM EDT	TSTM WND GST 60	Laurel, DE	WIND GUSTS BETWEEN 50 AND 60 MPH ESTIMATED IN LAUREL.
Aug 1, 5:53 PM EDT	HAIL 0.75	Laurel, DE	HAIL UP THE PENNY SIZE REPORTED IN LAUREL.
Aug 1, 6:05 PM EDT	TSTM WND GST 47	2 Sw Laurel, DE	A 47 MPH GUST WAS MEASURED AT THE LAUREL AIRPORT.
Aug 1, 6:20 PM EDT	HAIL 0.5	Delmar, DE	UP TO HALF INCH SIZE HAIL REPORTED IN DELMAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 9.5 hours before the alert went out and 74 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: 134 J/kg
Mixed-layer CIN: -156 J/kg
Mixed-layer LCL: 1051 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: -1 m²/s²
0-3 km storm-relative helicity: 26 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

978 
WUUS51 KPHI 012128
SVRPHI
DEC005-012215-
/O.NEW.KPHI.SV.W.0307.190801T2128Z-190801T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
528 PM EDT Thu Aug 1 2019

The National Weather Service in Mount Holly NJ has issued a

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

* Until 615 PM EDT.

* At 528 PM EDT, a severe thunderstorm was located over Seaford, or
  12 miles west of Georgetown, moving south 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...
  Seaford, Laurel, Delmar, Sycamore, Blades and Bethel. 

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.

&&

LAT...LON 3846 7569 3849 7570 3867 7571 3872 7571
      3874 7547 3845 7537
TIME...MOT...LOC 2128Z 354DEG 14KT 3869 7562 

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

Gorse

1 follow-up statement

071 
WWUS51 KPHI 012151
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
551 PM EDT Thu Aug 1 2019

DEC005-012215-
/O.CON.KPHI.SV.W.0307.000000T0000Z-190801T2215Z/
Sussex DE-
551 PM EDT Thu Aug 1 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR SOUTHWESTERN SUSSEX COUNTY...

At 550 PM EDT, a severe thunderstorm was located over Laurel, or 11
miles north of Salisbury, moving south at 25 mph.

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

SOURCE...Trained weather spotters. At 544 PM, 1 inch hail was 
         reported in Seaford.

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

Locations impacted include...
Seaford, Laurel, Delmar, Sycamore, Blades and Bethel. 

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.

&&

LAT...LON 3846 7569 3849 7570 3864 7571 3871 7565
      3874 7547 3845 7537
TIME...MOT...LOC 2150Z 344DEG 21KT 3854 7556 

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

Gorse

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 31, 8:39 PM EDT	Special Weather Statement	PHI	Sussex	36 min
Jul 31, 8:48 PM EDT	Special Weather Statement	PHI	Sussex	27 min
Jul 31, 9:18 PM EDT	Special Weather Statement	PHI	Sussex	27 min
Aug 1, 2:43 PM EDT	Special Weather Statement	PHI	Kent	47 min
Aug 1, 3:02 PM EDT	Coastal Flood Advisory	PHI	Kent, New Castle, Sussex	12 hr
Aug 1, 3:39 PM EDT	Special Weather Statement	PHI	Kent	51 min
Aug 1, 3:51 PM EDT	Special Weather Statement	PHI	Kent	39 min
Aug 1, 4:00 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	60 min
Aug 1, 4:06 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	54 min
Aug 1, 4:11 PM EDT	Special Weather Statement	PHI	New Castle	34 min
Aug 1, 4:41 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	21 min
Aug 1, 4:56 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	50 min
Aug 1, 6:16 PM EDT	Special Weather Statement	PHI	Sussex	14 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2019 Every severe thunderstorm warning in 2019

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.