Alert archive / Delaware / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 267, NWS Philadelphia/Mount Holly

August 19, 2011Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 19, 2011, 4:23 PM EDT for Sussex County, Delaware. It was in force for 82 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, 4:23 PM EDT (20:23 UTC)
Expired: Aug 19, 2011, 5:45 PM EDT
In force: 82 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 31 km from the middle of the area, began a volume at 20:24 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, 4:43 PM EDT	TSTM WND GST 58	Lewes, DE	ALSO WIRES DOWN ALONG COASTAL ROADWAY.

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, 8.4 hours before the alert went out and 87 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: 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.

798 
WUUS51 KPHI 192023
SVRPHI
DEC005-192145-
/O.NEW.KPHI.SV.W.0267.110819T2023Z-110819T2145Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  EAST CENTRAL SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 545 PM EDT

* AT 420 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
  LEWES...OR 14 MILES NORTHEAST OF GEORGETOWN...AND MOVING SOUTHEAST
  AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  LEWES AND CAPE HENLOPEN STATE PARK AROUND 435 PM EDT...
  REHOBOTH BEACH AROUND 515 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 3860 7514 3860 7511 3859 7509 3860 7508
      3862 7508 3861 7515 3883 7530 3887 7525
      3880 7516 3879 7511 3881 7509 3880 7507
      3860 7504 3855 7511
TIME...MOT...LOC 2023Z 334DEG 7KT 3880 7518

$$

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, 4:42 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.