Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 260, NWS Philadelphia/Mount Holly

August 19, 2011Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 19, 2011, 1:42 PM EDT for Sussex County, Delaware. It was in force for 63 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 19, 2011, 1:42 PM EDT (17:42 UTC)
Expired
Aug 19, 2011, 2:45 PM EDT
In force
63 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 30 km from the middle of the area, began a volume at 17:43 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.

What was reported inside it

TimeReportWhereRemark
Aug 19, 1:45 PM EDTHAIL 0.25Laurel, DE

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 5.7 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 2011-08-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 766 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 2011-08-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 15 square meters per square second.1939Sfc1 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
766 J/kg
Mixed-layer CIN
-78 J/kg
Mixed-layer LCL
1132 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
15 m²/s²
0-3 km storm-relative helicity
12 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

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

055 
WUUS51 KPHI 191742
SVRPHI
DEC005-191845-
/O.NEW.KPHI.SV.W.0260.110819T1742Z-110819T1845Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
142 PM EDT FRI AUG 19 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 245 PM EDT

* AT 137 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
  LAUREL...OR 12 MILES SOUTHWEST OF GEORGETOWN...AND MOVING EAST AT 5
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SYCAMORE AROUND 210 PM EDT...
  7 MILES WEST OF MILLSBORO...8 MILES NORTH OF GUMBORO AND 8 MILES
  SOUTH OF GEORGETOWN AROUND 245 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.

IN ADDITION TO LARGE HAIL AND 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 3846 7569 3865 7563 3878 7529 3847 7525
TIME...MOT...LOC 1742Z 261DEG 6KT 3857 7554

$$

TFG
1 follow-up statement
301 
WWUS51 KPHI 191810
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
210 PM EDT FRI AUG 19 2011

DEC005-191845-
/O.CON.KPHI.SV.W.0260.000000T0000Z-110819T1845Z/
SUSSEX DE-
210 PM EDT FRI AUG 19 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 245 PM EDT
FOR WESTERN SUSSEX COUNTY...

AT 208 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
LOCATED 6 MILES SOUTH OF BETHEL...OR 9 MILES NORTH OF 
SALISBURY...MOVING EAST AT 5 MPH. EXTREMELY HEAVY RAIN IS ALSO
FALLING WITH THIS STORM. 

THE SEVERE THUNDERSTORM WILL BE NEAR...
  BETHEL BY 225 PM EDT...
  LAUREL AND 8 MILES SOUTHWEST OF SYCAMORE BY 245 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 3846 7569 3865 7563 3878 7529 3847 7525
TIME...MOT...LOC 1810Z 261DEG 6KT 3849 7564

$$

TFG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 18, 8:26 PM EDTAreal Flood AdvisoryPHINew Castle112 min
Aug 19, 12:50 AM EDTSpecial Weather StatementPHINew Castle40 min
Aug 19, 1:14 AM EDTAreal Flood AdvisoryPHINew Castle3 hr
Aug 19, 1:44 AM EDTSpecial Weather StatementPHINew Castle61 min
Aug 19, 3:06 AM EDTAreal Flood AdvisoryPHIKent114 min
Aug 19, 4:00 AM EDTAreal Flood WarningPHINew Castle4 hr
Aug 19, 1:20 PM EDTSpecial Weather StatementPHIKent, Sussex85 min
Aug 19, 2:09 PM EDTAreal Flood AdvisoryPHISussex92 min
Aug 19, 2:33 PM EDTAreal Flood AdvisoryPHIKent, New Castle7 hr
Aug 19, 2:53 PM EDTSevere Thunderstorm WarningPHIKent, New Castle52 min
Aug 19, 2:59 PM EDTSevere Thunderstorm WarningPHISussex61 min
Aug 19, 3:13 PM EDTSpecial Weather StatementPHISussex92 min
Aug 19, 3:53 PM EDTAreal Flood AdvisoryPHIKent, Sussex5 hr
Aug 19, 4:09 PM EDTSevere Thunderstorm WarningPHIKent66 min
Aug 19, 4:23 PM EDTSevere Thunderstorm WarningPHISussex82 min
Aug 19, 4:42 PM EDTAreal Flood AdvisoryPHINew Castle4 hr
Aug 19, 4:42 PM EDTSevere Thunderstorm WarningPHIKent, Sussex63 min
Aug 19, 6:14 PM EDTSevere Thunderstorm WarningPHINew Castle65 min
Aug 19, 6:34 PM EDTAreal Flood AdvisoryPHISussex2 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.