Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 296, NWS Philadelphia/Mount Holly

August 25, 2011Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 25, 2011, 7:55 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 25, 2011, 7:55 PM EDT (23:55 UTC)
Expired: Aug 25, 2011, 8:46 PM EDT
In force: 51 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 31 km from the middle of the area, began a volume at 23:55 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, 11.9 hours before the alert went out and 84 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: 214 J/kg
Mixed-layer CIN: -199 J/kg
Mixed-layer LCL: 1221 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: -46 m²/s²
0-3 km storm-relative helicity: -12 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

082 
WUUS51 KPHI 252355
SVRPHI
DEC005-260100-
/O.NEW.KPHI.SV.W.0296.110825T2355Z-110826T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
755 PM EDT THU AUG 25 2011

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 900 PM EDT

* AT 751 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM GEORGETOWN TO MILLSBORO TO
  GUMBORO...OR ALONG A LINE EXTENDING FROM GEORGETOWN TO 8 MILES
  SOUTH OF GEORGETOWN TO 10 MILES NORTHEAST OF SALISBURY...AND MOVING
  NORTHEAST AT 35 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  MILLSBORO AROUND 800 PM EDT...
  MILTON AND DAGSBORO AROUND 805 PM EDT...
  SELBYVILLE AROUND 810 PM EDT...
  REHOBOTH BEACH...MILLVILLE AND LEWES AROUND 820 PM EDT...
  FENWICK ISLAND...CAPE HENLOPEN STATE PARK AND BETHANY BEACH AROUND
  825 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE 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 7543 3880 7550 3883 7521 3879 7513
      3879 7511 3881 7508 3878 7506 3874 7507
      3865 7505 3863 7506 3860 7504 3846 7503
      3844 7505
TIME...MOT...LOC 2355Z 244DEG 31KT 3875 7541 3859 7532
          3845 7539

$$

TFG

2 follow-up statements

668 
WWUS51 KPHI 260021
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
821 PM EDT THU AUG 25 2011

DEC005-260100-
/O.CON.KPHI.SV.W.0296.000000T0000Z-110826T0100Z/
SUSSEX DE-
821 PM EDT THU AUG 25 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 900 PM EDT
FOR EASTERN SUSSEX COUNTY...

AT 817 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER
SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS
WERE LOCATED ALONG A LINE EXTENDING FROM MILTON TO DAGSBORO TO
SELBYVILLE...OR ALONG A LINE EXTENDING FROM 6 MILES NORTHEAST OF
GEORGETOWN TO 12 MILES SOUTHEAST OF GEORGETOWN TO 17 MILES EAST OF
SALISBURY...MOVING EAST AT 25 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  MILLVILLE AND LEWES BY 835 PM EDT...
  REHOBOTH BEACH...OCEAN VIEW AND DEWEY BEACH BY 840 PM EDT...
  SOUTH BETHANY...FENWICK ISLAND...CAPE HENLOPEN STATE PARK AND
  BETHANY BEACH BY 845 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE 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 3847 7533 3880 7533 3883 7521 3879 7513
      3879 7511 3881 7508 3878 7506 3874 7507
      3865 7505 3863 7506 3860 7504 3846 7503
      3844 7505
TIME...MOT...LOC 0022Z 248DEG 23KT 3876 7527 3860 7518
          3846 7525

$$

TFG

021 
WWUS51 KPHI 260046
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
846 PM EDT THU AUG 25 2011

DEC005-260056-
/O.CAN.KPHI.SV.W.0296.000000T0000Z-110826T0100Z/
SUSSEX DE-
846 PM EDT THU AUG 25 2011

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

THE LINE OF THUNDERSTORMS MOVED OFFSHORE.

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 3847 7533 3880 7533 3883 7521 3879 7513
      3879 7511 3881 7508 3878 7506 3874 7507
      3865 7505 3863 7506 3860 7504 3846 7503
      3844 7505
TIME...MOT...LOC 0046Z 248DEG 23KT 3881 7508 3865 7499
          3851 7507

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 25, 10:00 AM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Aug 25, 11:19 AM EDT	Areal Flood Advisory	PHI	Kent, New Castle	3 hr
Aug 25, 11:50 AM EDT	Special Weather Statement	PHI	Kent	3 hr
Aug 25, 1:24 PM EDT	Special Weather Statement	PHI	Kent	96 min
Aug 25, 2:38 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	3 hr
Aug 25, 3:11 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	34 min
Aug 25, 3:47 PM EDT	Special Weather Statement	PHI	Kent	58 min
Aug 25, 4:36 PM EDT	Flood Watch	PHI	Kent, New Castle, Sussex	68 hr
Aug 25, 5:17 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	118 min
Aug 25, 5:26 PM EDT	Hurricane Watch	PHI	Kent, New Castle, Sussex	25 hr
Aug 25, 7:27 PM EDT	Special Weather Statement	PHI	Sussex	93 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2011 Every severe thunderstorm warning in 2011

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.