Alert archive / Delaware / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 92, NWS Philadelphia/Mount Holly

August 31, 2018Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 31, 2018, 1:09 PM EDT for Sussex County, Delaware. It was in force for 51 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 31, 2018, 1:09 PM EDT (17:09 UTC)
Expired
Aug 31, 2018, 2:00 PM EDT
In force
51 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), 10 km from the middle of the area, began a volume at 17:08 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, 5.2 hours before the alert went out and 95 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 12:00Z on 2018-08-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 72 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 12:00Z on 2018-08-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 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
72 J/kg
Mixed-layer CIN
-177 J/kg
Mixed-layer LCL
1245 m above ground
0-6 km bulk shear
23 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

653 
WUUS51 KPHI 311709
SVRPHI
DEC005-311800-
/O.NEW.KPHI.SV.W.0092.180831T1709Z-180831T1800Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
109 PM EDT FRI AUG 31 2018

The National Weather Service in Mount Holly NJ has issued a

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

* Until 200 PM EDT.

* At 108 PM EDT, a severe thunderstorm was located over Ellendale, or
  8 miles northwest of Georgetown, moving south at 10 mph.

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

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Georgetown, Milford, Seaford, Lewes, Milton, Bridgeville,
  Ellendale, Cape Henlopen State Park and Blades.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

Torrential rainfall with rainfall rates over 4 inches per hour is 
occurring with this storm, and will likely lead to flash flooding. 
Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3877 7560 3889 7550 3890 7539 3887 7530
      3889 7523 3881 7514 3881 7506 3875 7505
      3871 7522 3862 7533 3862 7565
TIME...MOT...LOC 1708Z 339DEG 9KT 3880 7547 

HAIL...0.75IN
WIND...60MPH
 
$$

Klein
3 follow-up statements
000 
WWUS51 KPHI 311728
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
128 PM EDT FRI AUG 31 2018

DEC005-311800-
/O.CON.KPHI.SV.W.0092.000000T0000Z-180831T1800Z/
Sussex DE-
128 PM EDT FRI AUG 31 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR CENTRAL SUSSEX COUNTY...

At 127 PM EDT, a severe thunderstorm was located over Ellendale, or
near Georgetown, moving southeast at 10 mph.

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

SOURCE...Radar indicated.

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

This severe storm will be near...
  Milton around 145 PM EDT.
  Georgetown around 200 PM EDT.

Other locations impacted by this severe thunderstorm include Blades.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

Torrential rainfall with rainfall rates over 4 inches per hour is 
occurring with this storm, and will likely lead to flash flooding. 
Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3879 7559 3883 7555 3884 7551 3888 7547
      3888 7540 3886 7528 3889 7524 3881 7514
      3881 7506 3875 7505 3871 7522 3862 7533
      3862 7565
TIME...MOT...LOC 1727Z 332DEG 7KT 3878 7543 

HAIL...0.75IN
WIND...60MPH
 
$$

Klein
006 
WWUS51 KPHI 311750
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
150 PM EDT FRI AUG 31 2018

DEC005-311800-
/O.CON.KPHI.SV.W.0092.000000T0000Z-180831T1800Z/
Sussex DE-
150 PM EDT FRI AUG 31 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 PM EDT
FOR CENTRAL SUSSEX COUNTY...

At 149 PM EDT, a severe thunderstorm was located near Ellendale, or
near Georgetown, moving south at 10 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

This severe storm will be near...
  Milton around 155 PM EDT.
  Georgetown around 200 PM EDT.

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 with rainfall rates near 4 inches per hour is 
occurring with this storm, and will likely lead to flash flooding. 
Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3864 7559 3881 7551 3885 7534 3887 7531
      3886 7527 3889 7524 3887 7521 3881 7518
      3868 7526 3862 7532
TIME...MOT...LOC 1749Z 338DEG 8KT 3876 7542 

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

JRK
094 
WWUS51 KPHI 311759
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
159 PM EDT FRI AUG 31 2018

DEC005-311809-
/O.EXP.KPHI.SV.W.0092.000000T0000Z-180831T1800Z/
Sussex DE-
159 PM EDT FRI AUG 31 2018

...THE SEVERE THUNDERSTORM WARNING FOR CENTRAL SUSSEX COUNTY WILL
EXPIRE AT 200 PM EDT...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning will be allowed to expire.  However gusty
winds and heavy rain are still possible with this thunderstorm.

To report severe weather, contact your nearest law enforcement 
agency. They will relay your report to the National Weather Service 
in Mount Holly NJ.

LAT...LON 3864 7559 3881 7551 3885 7534 3887 7531
      3886 7527 3889 7524 3887 7521 3881 7518
      3868 7526 3862 7532
TIME...MOT...LOC 1759Z 339DEG 9KT 3874 7541 

$$

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 31, 1:37 AM EDTSpecial Weather StatementPHISussex53 min
Aug 31, 10:57 AM EDTAreal Flood AdvisoryPHIKent107 min
Aug 31, 11:31 AM EDTFlash Flood WarningPHIKent11 hr
Aug 31, 11:53 AM EDTSpecial Weather StatementPHIKent37 min
Aug 31, 12:00 PM EDTSevere Thunderstorm WarningPHIKent15 min
Aug 31, 12:15 PM EDTFlash Flood WarningPHIKent, Sussex7 hr
Aug 31, 12:28 PM EDTSpecial Weather StatementPHIKent32 min
Aug 31, 12:35 PM EDTSevere Thunderstorm WarningPHIKent, Sussex40 min
Aug 31, 12:54 PM EDTFlash Flood WarningPHISussex4 hr
Aug 31, 1:58 PM EDTSpecial Weather StatementPHISussex32 min
Aug 31, 4:27 PM EDTSpecial Weather StatementPHISussex18 min
Aug 31, 4:32 PM EDTFlash Flood WarningPHISussex4 hr
Aug 31, 4:41 PM EDTAreal Flood AdvisoryPHIKent, New Castle4 hr
Aug 31, 4:42 PM EDTSpecial Weather StatementPHISussex33 min
Aug 31, 5:00 PM EDTFlash Flood WarningPHINew Castle4 hr
Aug 31, 5:14 PM EDTSpecial Weather StatementPHISussex46 min
Aug 31, 5:38 PM EDTAreal Flood AdvisoryPHIKent, New Castle, Sussex4 hr
Aug 31, 5:48 PM EDTFlash Flood WarningPHISussex3 hr
Aug 31, 7:11 PM EDTAreal Flood WarningPHIKent, Sussex4 hr
Aug 31, 7:37 PM EDTFlash Flood WarningPHIKent, New Castle4 hr

Nearby

Severe Thunderstorm Warnings in Delaware, 2018Every severe thunderstorm warning in 2018

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.