Alert archive / Delaware / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 108, NWS Philadelphia/Mount Holly

August 4, 2015Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 4, 2015, 6:20 PM EDT for Sussex County, Delaware. It was in force for 20 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 4, 2015, 6:20 PM EDT (22:20 UTC)
Expired
Aug 4, 2015, 6:40 PM EDT
In force
20 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 29 km from the middle of the area, began a volume at 22:22 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, 10.3 hours before the alert went out and 71 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 2015-08-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1672 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2015-08-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 square meters per square second.19395878Sfc1 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
1672 J/kg
Mixed-layer CIN
-94 J/kg
Mixed-layer LCL
1264 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
92 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

569 
WUUS51 KPHI 042220
SVRPHI
DEC005-042300-
/O.NEW.KPHI.SV.W.0108.150804T2220Z-150804T2300Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
620 PM EDT TUE AUG 4 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 700 PM EDT

* AT 619 PM EDT...DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
  CAPABLE OF PRODUCING QUARTER SIZE HAIL AND DAMAGING WINDS IN EXCESS
  OF 60 MPH. THIS STORM WAS LOCATED OVER HEBRON...OR 7 MILES
  NORTHWEST OF SALISBURY...AND MOVING NORTHEAST AT 30 MPH.

* LOCATIONS IMPACTED INCLUDE...
  GEORGETOWN...SEAFORD...MILLSBORO...LAUREL...MILTON...DELMAR...
  DAGSBORO...ELLENDALE...SYCAMORE...GUMBORO...LONG NECK...BLADES...
  FRANKFORD AND BETHEL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...LARGE HAIL...DEADLY
LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

&&

LAT...LON 3846 7569 3847 7569 3863 7571 3886 7539
      3861 7516 3860 7517 3859 7521 3858 7518
      3857 7518 3858 7514 3857 7515 3845 7541
TIME...MOT...LOC 2219Z 235DEG 28KT 3845 7570 

$$

SZATKOWSKI
1 follow-up statement
195 
WWUS51 KPHI 042240
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
640 PM EDT TUE AUG 4 2015

DEC005-042250-
/O.CAN.KPHI.SV.W.0108.000000T0000Z-150804T2300Z/
SUSSEX DE-
640 PM EDT TUE AUG 4 2015

...THE SEVERE THUNDERSTORM WARNING FOR SUSSEX COUNTY IS CANCELLED...
                
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 HAS BEEN CANCELLED.

LAT...LON 3846 7569 3847 7569 3863 7571 3886 7539
      3861 7516 3860 7517 3859 7521 3858 7518
      3857 7518 3858 7514 3857 7515 3845 7541
TIME...MOT...LOC 2239Z 235DEG 28KT 3854 7553 

$$

SZATKOWSKI

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 4, 4:20 AM EDTSevere Thunderstorm WarningPHINew Castle33 min
Aug 4, 5:37 AM EDTSevere Thunderstorm WarningPHIKent, New Castle34 min
Aug 4, 6:11 PM EDTSpecial Weather StatementPHISussex64 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2015Every severe thunderstorm warning in 2015

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.