Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 243, NWS Philadelphia/Mount Holly

August 15, 2011Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 15, 2011, 3:18 PM EDT for Kent County, Sussex County, Delaware. It was in force for 57 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 15, 2011, 3:18 PM EDT (19:18 UTC)
Expired
Aug 15, 2011, 4:15 PM EDT
In force
57 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), 9 km from the middle of the area, began a volume at 19:17 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 7.3 hours before the alert went out and 92 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-08-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 460 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, Phillips Aaf/Abe, MD at 12:00Z on 2011-08-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.1939587897Sfc1 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
460 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
689 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
31 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

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

643 
WUUS51 KPHI 151918
SVRPHI
DEC001-005-152015-
/O.NEW.KPHI.SV.W.0243.110815T1918Z-110815T2015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
318 PM EDT MON AUG 15 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 415 PM EDT

* AT 311 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR HARRINGTON...OR 15 MILES
  SOUTH OF DOVER...AND MOVING SOUTHEAST AT 25 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  MILFORD AROUND 330 PM EDT...
  ELLENDALE AROUND 340 PM EDT...
  7 MILES SOUTHWEST OF SLAUGHTER BEACH AROUND 345 PM EDT...
  MILTON AND 8 MILES NORTHEAST OF GEORGETOWN AROUND 355 PM EDT...
  LEWES AROUND 410 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO DAMAGING WINDS...HEAVY RAIN WILL OCCUR WITH THESE 
STORMS AND CAUSE LOW-LYING AND POOR DRAINAGE FLOODING.

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 3893 7574 3894 7573 3908 7554 3898 7529
      3893 7530 3889 7525 3886 7523 3881 7518
      3879 7513 3879 7511 3880 7509 3857 7534
TIME...MOT...LOC 1917Z 307DEG 22KT 3893 7556

$$

HEAVENER
2 follow-up statements
857 
WWUS51 KPHI 151943
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
343 PM EDT MON AUG 15 2011

DEC001-005-152015-
/O.CON.KPHI.SV.W.0243.000000T0000Z-110815T2015Z/
KENT DE-SUSSEX DE-
343 PM EDT MON AUG 15 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 PM EDT
FOR NORTH CENTRAL SUSSEX AND SOUTHEASTERN KENT COUNTIES...

AT 340 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR ELLENDALE...OR 11
MILES NORTH OF GEORGETOWN...MOVING SOUTHEAST AT 25 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  MILTON BY 355 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 3873 7539 3894 7562 3900 7545 3898 7529
      3893 7530 3889 7525 3886 7523 3882 7519
TIME...MOT...LOC 1943Z 307DEG 22KT 3883 7540

$$

HEAVENER
745 
WWUS51 KPHI 152006
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
406 PM EDT MON AUG 15 2011

DEC001-005-152016-
/O.EXP.KPHI.SV.W.0243.000000T0000Z-110815T2015Z/
KENT DE-SUSSEX DE-
406 PM EDT MON AUG 15 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL SUSSEX AND
SOUTHEASTERN KENT COUNTIES WILL EXPIRE AT 415 PM EDT...

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 3873 7539 3894 7562 3900 7545 3898 7529
      3893 7530 3889 7525 3886 7523 3882 7519
TIME...MOT...LOC 2006Z 307DEG 22KT 3874 7526

$$

HEAVENER

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 15, 12:56 AM EDTSpecial Weather StatementPHINew Castle64 min
Aug 15, 10:58 AM EDTSpecial Weather StatementPHIKent62 min
Aug 15, 1:05 PM EDTAreal Flood AdvisoryPHINew Castle4 hr
Aug 15, 1:38 PM EDTFlash Flood WarningPHIKent, New Castle4 hr
Aug 15, 2:47 PM EDTSpecial Weather StatementPHIKent58 min
Aug 15, 3:25 PM EDTSpecial Weather StatementPHIKent, Sussex3 hr

Nearby

Severe Thunderstorm Warnings in Delaware, 2011Every 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.