Alert archive / Delaware / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 197, NWS Philadelphia/Mount Holly

September 6, 2017Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 6, 2017, 6:00 PM EDT for Sussex County, Delaware. It was in force for 15 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: Sep 6, 2017, 6:00 PM EDT (22:00 UTC)
Expired: Sep 6, 2017, 6:15 PM EDT
In force: 15 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), 42 km from the middle of the area, began a volume at 22:02 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, 10.0 hours before the alert went out and 73 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: 379 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 849 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 65 m²/s²
0-3 km storm-relative helicity: 96 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 0.5

Open this sounding in Storm Lab

The text

As transmitted.

887 
WUUS51 KPHI 062200
SVRPHI
DEC005-062215-
/O.NEW.KPHI.SV.W.0197.170906T2200Z-170906T2215Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
600 PM EDT WED SEP 6 2017

The National Weather Service in Mount Holly NJ has issued a

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

* Until 615 PM EDT

* At 559 PM EDT, a severe thunderstorm was located over Ocean Pines,
  or near Ocean City, moving northeast at 30 mph.

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

  SOURCE...Radar indicated. 

  IMPACT...Minor damage to vehicles is possible. Expect damage to 
           trees and power lines. 

* This severe thunderstorm will be near,
  Millville around 615 PM EDT.
  Fenwick Island around 620 PM EDT. 

Other locations impacted by this severe thunderstorm include Long
Neck, Dewey Beach, Ocean View, South Bethany and Frankford.

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...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 3845 7529 3879 7506 3876 7505 3846 7504
      3846 7505 3845 7505
TIME...MOT...LOC 2159Z 217DEG 26KT 3839 7517 

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

JRK

1 follow-up statement

667 
WWUS51 KPHI 062219
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
619 PM EDT WED SEP 6 2017

DEC005-062227-
/O.EXP.KPHI.SV.W.0197.000000T0000Z-170906T2215Z/
Sussex DE-
619 PM EDT WED SEP 6 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN SUSSEX COUNTY HAS
EXPIRED...
        
The storm which prompted the warning has quickly weakened to below 
severe limits as it moves off the southern Delaware coast. 
Therefore, the warning has been allowed to expire.  However small 
hail, gusty winds and heavy rain are still possible with this 
thunderstorm.

LAT...LON 3845 7529 3879 7506 3876 7505 3846 7504
      3846 7505 3845 7505
TIME...MOT...LOC 2217Z 217DEG 26KT 3849 7507 

$$

JRK

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 5, 11:27 PM EDT	Special Weather Statement	PHI	Sussex	48 min
Sep 6, 12:01 AM EDT	Special Weather Statement	PHI	Sussex	44 min
Sep 6, 5:07 PM EDT	Special Weather Statement	PHI	Sussex	68 min
Sep 6, 6:16 PM EDT	Special Weather Statement	PHI	Sussex	44 min
Sep 6, 6:26 PM EDT	Areal Flood Advisory	PHI	Sussex	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.