Alert archive / Delaware / Severe Thunderstorm Warnings in 2019

Severe Thunderstorm Warning 234, NWS Philadelphia/Mount Holly

July 17, 2019Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 17, 2019, 8:54 PM EDT for Sussex County, Delaware. It was in force for 36 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: Jul 17, 2019, 8:54 PM EDT (00:54 UTC)
Expired: Jul 17, 2019, 9:30 PM EDT
In force: 36 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 34 km from the middle of the area, began a volume at 00:53 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Jul 17, 4:51 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 0.9 hours before the alert went out and 82 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: 1810 J/kg
Mixed-layer CIN: -39 J/kg
Mixed-layer LCL: 1434 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 112 m²/s²
0-3 km storm-relative helicity: 169 m²/s²
Significant tornado parameter: 0.5
Supercell composite: 3.5

Open this sounding in Storm Lab

The text

As transmitted.

980 
WUUS51 KPHI 180054
SVRPHI
DEC005-180130-
/O.NEW.KPHI.SV.W.0234.190718T0054Z-190718T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
854 PM EDT Wed Jul 17 2019

The National Weather Service in Mount Holly NJ has issued a

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

* Until 930 PM EDT.

* At 853 PM EDT, a severe thunderstorm was located near Milton, or
  near Georgetown, moving east at 20 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

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 3876 7534 3881 7519 3879 7510
      3880 7510 3867 7507 3869 7508 3869 7514
      3864 7513 3862 7508 3866 7507 3861 7506
      3859 7521 3857 7518 3858 7507 3860 7506
      3845 7505
TIME...MOT...LOC 0053Z 249DEG 17KT 3870 7529 

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

Fitzsimmons

1 follow-up statement

486 
WWUS51 KPHI 180109
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
909 PM EDT Wed Jul 17 2019

DEC005-180130-
/O.CON.KPHI.SV.W.0234.000000T0000Z-190718T0130Z/
Sussex DE-
909 PM EDT Wed Jul 17 2019

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR SOUTHEASTERN SUSSEX COUNTY...

At 909 PM EDT, a severe thunderstorm was located near Henlopen Acres,
or 11 miles east of Georgetown, moving east at 20 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3876 7534 3881 7519 3879 7510 3880 7510
      3867 7507 3869 7508 3869 7514 3864 7513
      3862 7508 3866 7507 3861 7506 3859 7521
      3857 7518 3858 7507 3860 7506 3845 7505
      3845 7529
TIME...MOT...LOC 0109Z 255DEG 18KT 3870 7518 

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

Fitzsimmons

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 17, 8:30 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	45 min
Jul 17, 9:09 PM EDT	Areal Flood Advisory	PHI	Sussex	2 hr
Jul 17, 11:34 PM EDT	Areal Flood Advisory	PHI	Sussex	2 hr
Jul 18, 1:30 PM EDT	Areal Flood Advisory	PHI	New Castle	4 hr
Jul 18, 2:24 PM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Jul 18, 2:55 PM EDT	Flash Flood Warning	PHI	New Castle	4 hr

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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.