Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 178, NWS Philadelphia/Mount Holly

July 19, 2011Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 19, 2011, 4:40 PM EDT for Sussex County, Delaware. It was in force for 32 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
Jul 19, 2011, 4:40 PM EDT (20:40 UTC)
Expired
Jul 19, 2011, 5:12 PM EDT
In force
32 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 12 km from the middle of the area, began a volume at 20:42 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, 8.7 hours before the alert went out and 89 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 2011-07-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 161 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°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 2011-07-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 74 square meters per square second.193958Sfc1 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
161 J/kg
Mixed-layer CIN
-135 J/kg
Mixed-layer LCL
1267 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
74 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

408 
WUUS51 KPHI 192040
SVRPHI
DEC005-192215-
/O.NEW.KPHI.SV.W.0178.110719T2040Z-110719T2215Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
440 PM EDT TUE JUL 19 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 615 PM EDT

* AT 438 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
  ELLENDALE...OR 12 MILES NORTH OF GEORGETOWN...AND MOVING SOUTHEAST
  AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ELLENDALE AROUND 505 PM EDT...
  MILTON AROUND 535 PM EDT...
  GEORGETOWN AROUND 555 PM EDT...
  GEORGETOWN AROUND 600 PM EDT...
  6 MILES NORTHWEST OF MILLSBORO AROUND 615 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...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES GREATEST 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 3849 7542 3883 7562 3884 7557 3884 7555
      3886 7553 3894 7539 3868 7512 3865 7511
      3864 7508
TIME...MOT...LOC 2040Z 333DEG 8KT 3885 7546

$$

NIERENBERG
1 follow-up statement
271 
WWUS51 KPHI 192112
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
512 PM EDT TUE JUL 19 2011

DEC005-192121-
/O.CAN.KPHI.SV.W.0178.000000T0000Z-110719T2215Z/
SUSSEX DE-
512 PM EDT TUE JUL 19 2011

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

THE THUNDERSTORM COMPLEX THAT WAS MOVING THROUGH NORTHERN AND 
CENTRAL SUSSEX COUNTY LATE THIS AFTERNOON HAS WEAKENED AND NO LONGER 
POSES A THREAT FOR SEVERE WEATHER. THE SEVERE THUNDERSTORM WARNING 
HAS THEREFORE BEEN CANCELLED.


LAT...LON 3849 7542 3883 7562 3884 7557 3884 7555
      3886 7553 3894 7539 3868 7512 3865 7511
      3864 7508
TIME...MOT...LOC 2111Z 333DEG 8KT 3879 7542

$$
JJM

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 19, 6:02 AM EDTHeat AdvisoryPHINew Castle13 hr
Jul 19, 2:13 PM EDTSpecial Weather StatementPHIKent, New Castle, Sussex92 min
Jul 19, 2:29 PM EDTExcessive Heat WarningPHIKent, New Castle, Sussex5 days
Jul 19, 2:43 PM EDTSevere Thunderstorm WarningPHIKent, Sussex92 min
Jul 19, 3:45 PM EDTAreal Flood AdvisoryPHIKent, Sussex3 hr
Jul 19, 4:12 PM EDTFlash Flood WarningPHIKent3 hr
Jul 19, 4:25 PM EDTSpecial Weather StatementPHIKent, Sussex80 min

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.