Alert archive / Delaware / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

August 18, 2017Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this special weather statement at Aug 18, 2017, 8:43 PM EDT for Sussex County, Delaware. It was in force for 32 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 18, 2017, 8:43 PM EDT (00:43 UTC)
Expired
Aug 18, 2017, 9:15 PM EDT
In force
32 min
Issued by
NWS Philadelphia/Mount Holly

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 22 km from the middle of the area, began a volume at 00:47 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, 0.7 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-pSkew-T log-p diagram, Wallops Is Stn, VA at 00:00Z on 2017-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 394 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 2017-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 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
394 J/kg
Mixed-layer CIN
-110 J/kg
Mixed-layer LCL
1406 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
52 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

095 
WWUS81 KPHI 190043
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
843 PM EDT FRI AUG 18 2017

DEZ002>004-MDZ019-020-190115-
Inland Sussex-Kent-Delaware Beaches-Talbot-Caroline-
843 PM EDT FRI AUG 18 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SUSSEX...SOUTHERN
KENT...EAST CENTRAL TALBOT AND SOUTHERN CAROLINE COUNTIES...

At 842 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Milton to near Seaford. Movement was
southeast at 20 mph.

Winds up to 30 mph and pea size hail are possible with these storms.

Locations impacted include...
Georgetown, Milford, Seaford, Millsboro, Laurel, Harrington, Lewes,
Federalsburg, Milton, Selbyville, Bridgeville, Delmar, Dagsboro,
Preston, Millville, Ellendale, Henlopen Acres, Smithville, Gumboro
and Agner.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 3846 7569 3865 7571 3871 7584 3867 7596
      3874 7604 3900 7545 3876 7508 3867 7507
      3869 7514 3862 7508 3866 7507 3866 7506
      3861 7506 3859 7521 3860 7506 3851 7505
      3845 7522
TIME...MOT...LOC 0042Z 310DEG 19KT 3873 7526 3861 7567 

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 8:26 PM EDTSpecial Weather StatementPHIAtlantic, Cape May, Ocean49 min
Aug 19, 7:55 PM EDTSpecial Weather StatementPHIBerks65 min
Aug 18, 9:08 PM EDTSpecial Weather StatementPHISussex52 min
Aug 18, 9:55 PM EDTSpecial Weather StatementPHISussex50 min

Nearby

Special Weather Statements in Delaware, 2017Every special weather statement 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.