Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 263, NWS Philadelphia/Mount Holly

August 19, 2011Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 19, 2011, 2:53 PM EDT for Kent County, New Castle County, Delaware. It was in force for 52 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, 2:53 PM EDT (18:53 UTC)
Expired: Aug 19, 2011, 3:45 PM EDT
In force: 52 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Kent County, DE, New Castle County, DE

The radar

The Dover AFB radar (KDOX), 54 km from the middle of the area, began a volume at 18:55 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.

What was reported inside it

Time	Report	Where	Remark
Aug 19, 3:00 PM EDT	TSTM WND DMG	Clayton, DE	STRUCTURAL DAMAGE FROM THUNDERSTORM WIND GUST

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

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Aug 19, 1:04 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 6.9 hours before the alert went out and 51 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: 146 J/kg
Mixed-layer CIN: -154 J/kg
Mixed-layer LCL: 1250 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: 359 m²/s²
0-3 km storm-relative helicity: 370 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.

572 
WUUS51 KPHI 191853
SVRPHI
DEC001-003-191945-
/O.NEW.KPHI.SV.W.0263.110819T1853Z-110819T1945Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN KENT COUNTY IN CENTRAL DELAWARE...
  THIS INCLUDES THE CITY OF DOVER...
  SOUTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...

* UNTIL 345 PM EDT

* AT 251 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
  CHESWOLD...OR 7 MILES NORTHWEST OF DOVER...AND MOVING EAST AT 10
  MPH. ANOTHER DEVELOPING STORM THAT MIGHT ALSO BECOME SEVERE WAS
  JUST CROSSING INTO SOUTHWESTERN NEW CASTLE COUNTY FROM KENT COUNTY.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  CHESWOLD AROUND 305 PM EDT...
  7 MILES NORTH OF CAMDEN AROUND 320 PM EDT...
  DOVER SPEEDWAY AROUND 325 PM EDT...
  DOVER AROUND 330 PM EDT...
  9 MILES SOUTH OF WOODLAND BEACH AROUND 335 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.

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 3907 7561 3925 7577 3934 7577 3954 7559
      3951 7557 3946 7558 3942 7553 3935 7548
      3932 7543 3924 7538 3920 7538 3914 7541
TIME...MOT...LOC 1852Z 276DEG 8KT 3922 7562

$$

TFG

1 follow-up statement

024 
WWUS51 KPHI 191921
SVSPHI

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

DEC001-003-191945-
/O.CON.KPHI.SV.W.0263.000000T0000Z-110819T1945Z/
KENT DE-NEW CASTLE DE-
321 PM EDT FRI AUG 19 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 345 PM EDT
FOR SOUTHERN NEW CASTLE AND NORTHEASTERN KENT COUNTIES...

AT 316 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 GREEN SPRING TO SMYRNA TO
DOVER SPEEDWAY...OR ALONG A LINE EXTENDING FROM 8 MILES SOUTH OF
MIDDLETOWN TO 11 MILES NORTH OF DOVER TO DOVER...MOVING EAST AT 10
MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  LEIPSIC BY 330 PM EDT...
  LITTLE CREEK BY 340 PM EDT...
  CHAMBERSVILLE AND 9 MILES WEST OF WOODLAND BEACH BY 345 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 3915 7557 3927 7568 3934 7577 3948 7563
      3946 7559 3946 7558 3942 7553 3935 7548
      3932 7543 3924 7538 3920 7538 3914 7541
TIME...MOT...LOC 1921Z 276DEG 8KT 3933 7571 3930 7558
          3918 7550

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 18, 8:26 PM EDT	Areal Flood Advisory	PHI	New Castle	112 min
Aug 19, 12:50 AM EDT	Special Weather Statement	PHI	New Castle	40 min
Aug 19, 1:14 AM EDT	Areal Flood Advisory	PHI	New Castle	3 hr
Aug 19, 1:44 AM EDT	Special Weather Statement	PHI	New Castle	61 min
Aug 19, 3:06 AM EDT	Areal Flood Advisory	PHI	Kent	114 min
Aug 19, 4:00 AM EDT	Areal Flood Warning	PHI	New Castle	4 hr
Aug 19, 1:20 PM EDT	Special Weather Statement	PHI	Kent, Sussex	85 min
Aug 19, 1:42 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	63 min
Aug 19, 2:09 PM EDT	Areal Flood Advisory	PHI	Sussex	92 min
Aug 19, 2:33 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	7 hr
Aug 19, 2:59 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	61 min
Aug 19, 3:13 PM EDT	Special Weather Statement	PHI	Sussex	92 min
Aug 19, 3:53 PM EDT	Areal Flood Advisory	PHI	Kent, Sussex	5 hr
Aug 19, 4:09 PM EDT	Severe Thunderstorm Warning	PHI	Kent	66 min
Aug 19, 4:23 PM EDT	Severe Thunderstorm Warning	PHI	Sussex	82 min
Aug 19, 4:42 PM EDT	Areal Flood Advisory	PHI	New Castle	4 hr
Aug 19, 4:42 PM EDT	Severe Thunderstorm Warning	PHI	Kent, Sussex	63 min
Aug 19, 6:14 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	65 min
Aug 19, 6:34 PM EDT	Areal Flood Advisory	PHI	Sussex	2 hr

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.