Alert archive / Delaware / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 233, NWS Philadelphia/Mount Holly

September 18, 2012Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 18, 2012, 7:08 PM EDT for Sussex County, Delaware. It was in force for 38 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
Sep 18, 2012, 7:08 PM EDT (23:08 UTC)
Expired
Sep 18, 2012, 7:46 PM EDT
In force
38 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 28 km from the middle of the area, began a volume at 23:11 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.

IssuedProductOfficeLasted
Sep 18, 12:10 PM EDTTornado WatchSPC9 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.1 hours before the alert went out and 85 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 2012-09-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 205 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 2012-09-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 134 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
205 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
778 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
134 m²/s²
0-3 km storm-relative helicity
150 m²/s²
Significant tornado parameter
0.1
Supercell composite
0.9

Open this sounding in Storm Lab

The text

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

256 
WUUS51 KPHI 182308
SVRPHI
DEC005-190015-
/O.NEW.KPHI.SV.W.0233.120918T2308Z-120919T0015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
708 PM EDT TUE SEP 18 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EASTERN SUSSEX COUNTY IN SOUTHERN DELAWARE...
  THIS INCLUDES THE CITY OF GEORGETOWN...

* UNTIL 815 PM EDT

* AT 705 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM SLAUGHTER BEACH TO GUMBORO...AND MOVING NORTHEAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  SELBYVILLE AROUND 715 PM EDT...
  MILLSBORO AND DAGSBORO AROUND 720 PM EDT...
  FENWICK ISLAND AROUND 725 PM EDT...
  BETHANY BEACH...MILLVILLE AND LEWES AROUND 730 PM EDT...
  REHOBOTH BEACH AND CAPE HENLOPEN STATE PARK AROUND 735 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED... ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS...HAIL...AND DEADLY CLOUD TO GROUND 
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY 
INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 3845 7551 3895 7539 3895 7532 3880 7517
      3879 7511 3881 7510 3880 7508 3867 7505
      3862 7505 3861 7504 3845 7504 3844 7505
TIME...MOT...LOC 2308Z 234DEG 39KT 3894 7530 3848 7542

$$

IOVINO
2 follow-up statements
616 
WWUS51 KPHI 182329
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
729 PM EDT TUE SEP 18 2012

DEC005-190015-
/O.CON.KPHI.SV.W.0233.000000T0000Z-120919T0015Z/
SUSSEX DE-
729 PM EDT TUE SEP 18 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 815 PM EDT
FOR EASTERN SUSSEX COUNTY...

AT 725 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE 
EXTENDING FROM MILTON TO MILLSBORO TO FRANKFORD...MOVING NORTHEAST 
AT 45 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  OCEAN VIEW BY 730 PM EDT...
  SOUTH BETHANY...BETHANY BEACH...REHOBOTH BEACH AND CAPE HENLOPEN
  STATE PARK BY 735 PM EDT...
  DEWEY BEACH BY 740 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT FOR THE WARNED AREA. IF A TORNADO
IS SPOTTED... ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A STURDY
STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS...HAIL...AND DEADLY CLOUD TO GROUND 
LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...PREFERABLY 
INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

&&

LAT...LON 3846 7536 3895 7532 3880 7517 3879 7511
      3881 7510 3880 7508 3867 7505 3862 7505
      3861 7504 3845 7504 3844 7505
TIME...MOT...LOC 2327Z 234DEG 39KT 3906 7508 3860 7521

$$

IOVINO
933 
WWUS51 KPHI 182346
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
746 PM EDT TUE SEP 18 2012

DEC005-182356-
/O.CAN.KPHI.SV.W.0233.000000T0000Z-120919T0015Z/
SUSSEX DE-
746 PM EDT TUE SEP 18 2012

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN SUSSEX COUNTY IS
CANCELLED...

THE STRONG THUNDERSTORMS HAVE PASSED OFF THE COAST. AS A 
RESULT...THE SEVERE THUNDERSTORM WARNING HAS BEEN CANCELLED.


PLEASE REPORT HAIL OR STRONG WINDS TO THE NATIONAL WEATHER SERVICE BY
CALLING TOLL FREE...1-877-633-6772...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3846 7536 3895 7532 3880 7517 3879 7511
      3881 7510 3880 7508 3867 7505 3862 7505
      3861 7504 3845 7504 3844 7505
TIME...MOT...LOC 2346Z 234DEG 39KT 3918 7486 3872 7500

$$

IOVINO

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 17, 8:54 PM EDTRip Current StatementPHISussex23 hr
Sep 18, 4:13 AM EDTCoastal Flood AdvisoryPHINew Castle21 hr
Sep 18, 4:21 PM EDTSevere Thunderstorm WarningPHINew Castle69 min
Sep 18, 5:12 PM EDTAreal Flood AdvisoryPHINew Castle63 min
Sep 18, 5:23 PM EDTSevere Thunderstorm WarningPHINew Castle52 min
Sep 18, 5:57 PM EDTSevere Thunderstorm WarningPHIKent, Sussex78 min
Sep 18, 7:16 PM EDTAreal Flood AdvisoryPHISussex59 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2012Every severe thunderstorm warning in 2012

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.