Alert archive / Delaware / Special Weather Statements in 2017

Special Weather Statement, NWS Philadelphia/Mount Holly

June 21, 2017Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this special weather statement at Jun 21, 2017, 9:15 PM EDT for Sussex County, Delaware. It was in force for 30 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 21, 2017, 9:15 PM EDT (01:15 UTC)
Expired
Jun 21, 2017, 9:45 PM EDT
In force
30 min
Issued by
NWS Philadelphia/Mount Holly

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 33 km from the middle of the area, began a volume at 01:15 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, 1.3 hours before the alert went out and 80 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 2017-06-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 239 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 2017-06-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.1939587897Sfc1 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
239 J/kg
Mixed-layer CIN
-33 J/kg
Mixed-layer LCL
1243 m above ground
0-6 km bulk shear
61 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
79 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.1

Open this sounding in Storm Lab

The text

As transmitted.

551 
WWUS81 KPHI 220115
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
915 PM EDT WED JUN 21 2017

DEZ003-004-220145-
Inland Sussex-Delaware Beaches-
915 PM EDT WED JUN 21 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT SOUTHEASTERN SUSSEX
COUNTY...

At 914 PM EDT, radar indicated strong thunderstorms were located
along a line extending from Henlopen Acres to near Georgetown.
Movement was southeast at 30 mph.

Winds up to 45 mph and pea size hail are possible with these storms.

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

Brief heavy downpours can be expected, which will reduce visibility 
below one mile and cause ponding of water on roadways.

These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 3869 7553 3879 7509 3867 7507 3869 7508
      3869 7514 3864 7513 3862 7508 3866 7507
      3861 7506 3859 7521 3857 7518 3858 7507
      3860 7509 3860 7506 3845 7505 3845 7536
TIME...MOT...LOC 0114Z 326DEG 25KT 3873 7509 3866 7541 

$$

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 21, 8:18 PM EDTSpecial Weather StatementPHICape May27 min
Jun 21, 8:22 PM EDTSpecial Marine WarningPHI83 min
Jun 21, 9:06 PM EDTSpecial Marine WarningPHI84 min
Jun 22, 3:31 AM EDTCoastal Flood AdvisoryPHIAtlantic, Burlington, Cape May, Middlesex, Monmouth, Ocean17 hr
Jun 22, 3:55 PM EDTSmall Craft AdvisoryPHI60 hr
Jun 21, 8:51 PM EDTSpecial Weather StatementPHISussex24 min
Jun 21, 9:46 PM EDTSpecial Weather StatementPHISussex29 min
Jun 21, 10:32 PM EDTSpecial Weather StatementPHISussex58 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.