Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 270, NWS Philadelphia/Mount Holly

August 19, 2011Kent County, Sussex County, Delaware; Caroline County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 19, 2011, 4:42 PM EDT for Kent County, Sussex County, Delaware; Caroline County, Maryland. It was in force for 63 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 19, 2011, 4:42 PM EDT (20:42 UTC)
Expired: Aug 19, 2011, 5:45 PM EDT
In force: 63 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Kent County, DE, Sussex County, DE, Caroline County, MD

The radar

The Dover AFB radar (KDOX), 18 km from the middle of the area, began a volume at 20:45 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, 8.7 hours before the alert went out and 74 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.

940 
WUUS51 KPHI 192042
SVRPHI
DEC001-005-MDC011-192145-
/O.NEW.KPHI.SV.W.0270.110819T2042Z-110819T2145Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN KENT COUNTY IN CENTRAL DELAWARE...
  CENTRAL CAROLINE COUNTY IN EASTERN MARYLAND...
  NORTHWESTERN SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 545 PM EDT

* AT 441 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
  DENTON...OR 16 MILES EAST OF EASTON...AND MOVING NORTHEAST AT 15
  MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ANDREWSVILLE AROUND 510 PM EDT...
  HARRINGTON AROUND 530 PM EDT...
  VIOLA AROUND 540 PM EDT...
  6 MILES NORTHWEST OF MILFORD AND 8 MILES SOUTHWEST OF BOWERS AROUND
  545 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.

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 3888 7591 3915 7541 3912 7539 3907 7539
      3903 7533 3898 7529 3892 7530 3873 7582
TIME...MOT...LOC 2042Z 239DEG 14KT 3885 7579

$$

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, 2:53 PM EDT	Severe Thunderstorm Warning	PHI	Kent, New Castle	52 min
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, 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
Aug 18, 8:35 PM EDT	Special Weather Statement	PHI	Queen Anne's	55 min
Aug 19, 12:02 AM EDT	Special Weather Statement	PHI	Cecil	58 min
Aug 19, 1:00 AM EDT	Special Weather Statement	PHI	Cecil	45 min
Aug 19, 4:53 PM EDT	Areal Flood Advisory	PHI	Caroline, Cecil, Kent, Queen Anne's	5 hr
Aug 19, 5:35 PM EDT	Severe Thunderstorm Warning	PHI	Cecil	55 min
Aug 19, 5:39 PM EDT	Areal Flood Advisory	PHI	Cecil	3 hr
Aug 19, 6:18 PM EDT	Areal Flood Advisory	PHI	Caroline, Kent, Queen Anne's, Talbot	3 hr
Aug 19, 6:21 PM EDT	Severe Thunderstorm Warning	PHI	Cecil, Kent, Queen Anne's	69 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2011 Severe Thunderstorm Warnings in Maryland, 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.