Alert archive / Delaware / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 157, NWS Philadelphia/Mount Holly

August 7, 2017Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 7, 2017, 1:58 PM EDT for Sussex County, Delaware. It was in force for 47 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 7, 2017, 1:58 PM EDT (17:58 UTC)
Expired: Aug 7, 2017, 2:45 PM EDT
In force: 47 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 60.0 mph

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 28 km from the middle of the area, began a volume at 17:58 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, 6.0 hours before the alert went out and 79 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: 57 J/kg
Mixed-layer CIN: -91 J/kg
Mixed-layer LCL: 996 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 176 m²/s²
0-3 km storm-relative helicity: 193 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

Open this sounding in Storm Lab

The text

As transmitted.

826 
WUUS51 KPHI 071758
SVRPHI
DEC005-071845-
/O.NEW.KPHI.SV.W.0157.170807T1758Z-170807T1845Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
158 PM EDT MON AUG 7 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 245 PM EDT

* At 157 PM EDT, a severe thunderstorm was located over Gumboro, or
  14 miles northeast of Salisbury, moving northeast at 55 mph.

  HAZARD...60 mph wind gusts. 

  SOURCE...Radar indicated. 

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

* Locations impacted include...
  Georgetown, Millsboro, Lewes, Selbyville, Delmar, Dagsboro,
  Millville, Henlopen Acres, Gumboro, Cape Henlopen State Park, Long
  Neck, Ocean View, Frankford, South Bethany and Dewey Beach.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 3846 7559 3887 7521 3881 7514 3881 7506
      3854 7504 3845 7505
TIME...MOT...LOC 1757Z 221DEG 46KT 3847 7535 

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

CMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 7, 9:59 AM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Aug 7, 10:44 AM EDT	Flash Flood Warning	PHI	Kent	4 hr
Aug 7, 11:41 AM EDT	Areal Flood Advisory	PHI	Kent, Sussex	3 hr
Aug 7, 12:36 PM EDT	Areal Flood Advisory	PHI	Kent	4 hr
Aug 7, 1:47 PM EDT	Special Weather Statement	PHI	Sussex	43 min
Aug 7, 2:06 PM EDT	Flash Flood Warning	PHI	Kent, Sussex	4 hr
Aug 7, 2:08 PM EDT	Tornado Warning	PHI	Sussex	37 min
Aug 7, 2:22 PM EDT	Areal Flood Advisory	PHI	Sussex	4 hr
Aug 7, 2:40 PM EDT	Areal Flood Warning	PHI	Kent	6 hr
Aug 7, 2:41 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	34 min
Aug 7, 4:57 PM EDT	Areal Flood Warning	PHI	Sussex	4 hr
Aug 7, 5:25 PM EDT	Areal Flood Warning	PHI	Kent	4 hr

Nearby

Severe Thunderstorm Warnings in Delaware, 2017 Every 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.