Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 294, NWS Philadelphia/Mount Holly

August 25, 2011Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 25, 2011, 3:11 PM EDT for Kent County, Sussex County, Delaware. It was in force for 34 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, 3:11 PM EDT (19:11 UTC)
Expired: Aug 25, 2011, 3:45 PM EDT
In force: 34 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Kent County, DE, Sussex County, DE

The radar

The Dover AFB radar (KDOX), 14 km from the middle of the area, began a volume at 19:11 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 nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 7.2 hours before the alert went out and 111 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.

768 
WUUS51 KPHI 251911
SVRPHI
DEC001-005-251945-
/O.NEW.KPHI.SV.W.0294.110825T1911Z-110825T1945Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL KENT COUNTY IN CENTRAL DELAWARE...
  NORTH CENTRAL SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 345 PM EDT

* AT 307 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  MILFORD...OR 15 MILES NORTH OF GEORGETOWN...AND MOVING NORTHEAST AT
  35 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO
  SLAUGHTER BEACH AND BIG STONE BEACH

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 3883 7545 3899 7556 3906 7537 3903 7533
      3898 7529 3893 7530 3889 7525 3881 7519
TIME...MOT...LOC 1911Z 241DEG 31KT 3891 7544

$$

TFG

1 follow-up statement

402 
WWUS51 KPHI 251928
SVSPHI

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

DEC001-005-251945-
/O.CON.KPHI.SV.W.0294.000000T0000Z-110825T1945Z/
KENT DE-SUSSEX DE-
328 PM EDT THU AUG 25 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR NORTH CENTRAL SUSSEX AND EAST CENTRAL KENT COUNTIES...

AT 324 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE 
HAIL...AND DAMAGING WINDS TO 60 MPH.  THIS STORM WAS LOCATED NEAR 
MILFORD...OR 16 MILES NORTH OF GEORGETOWN...MOVING NORTHEAST AT 35 
MPH. A SECOND LIKELY SEVERE THUNDERSTORM IS ENTERING DELAWARE BAY
NEAR BIG STONE BEACH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
SLAUGHTER BEACH

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CLOUD TO GROUND 
LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY! 
LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS. REMEMBER...IF YOU 
CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

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 3889 7527 3883 7543 3899 7556 3906 7537
      3903 7533 3898 7529 3893 7530 3889 7525
TIME...MOT...LOC 1927Z 241DEG 31KT 3893 7540

$$

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, 3:47 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
Aug 25, 7:55 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	51 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.