Alert archive / Maryland / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 173, NWS Philadelphia/Mount Holly

July 11, 20114 counties in Maryland; Kent County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 11, 2011, 9:33 PM EDT for 4 counties in Maryland; Kent County, Delaware. It was in force for 57 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 11, 2011, 9:33 PM EDT (01:33 UTC)
Expired
Jul 11, 2011, 10:30 PM EDT
In force
57 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Kent County, DE, Caroline County, MD, Kent County, MD, Queen Anne's County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 65 km from the middle of the area, began a volume at 01:34 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 watch it was issued in

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

IssuedProductOfficeLasted
Jul 11, 9:01 PM EDTSevere Thunderstorm WatchSPC3 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 1.6 hours before the alert went out and 105 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, Washington/Dulle, VA at 00:00Z on 2011-07-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3066 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, Washington/Dulle, VA at 00:00Z on 2011-07-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 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
3066 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
1246 m above ground
0-6 km bulk shear
20 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
166 m²/s²
Significant tornado parameter
0.0
Supercell composite
8.0

Open this sounding in Storm Lab

The text

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

279 
WUUS51 KPHI 120133
SVRPHI
DEC001-MDC011-029-035-041-120230-
/O.NEW.KPHI.SV.W.0173.110712T0133Z-110712T0230Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
933 PM EDT MON JUL 11 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN KENT COUNTY IN CENTRAL DELAWARE...
  CAROLINE COUNTY IN EASTERN MARYLAND...
  TALBOT COUNTY IN EASTERN MARYLAND...
  THIS INCLUDES THE CITY OF EASTON...
  EXTREME SOUTHWESTERN KENT COUNTY IN NORTHEAST MARYLAND...
  SOUTHERN QUEEN ANNE'S COUNTY IN NORTHEAST MARYLAND...
  THIS INCLUDES THE CITY OF CENTERVILLE...

* UNTIL 1030 PM EDT

* AT 930 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM 8 MILES NORTHWEST OF STEVENSVILLE TO 11 MILES WEST OF TALBOT
  TO 33 MILES SOUTHWEST OF TILGHMAN ISLAND...OR ALONG A LINE
  EXTENDING FROM 17 MILES WEST OF CENTERVILLE TO 23 MILES WEST OF
  EASTON TO 45 MILES SOUTHWEST OF EASTON...AND MOVING EAST AT 35 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  STEVENSVILLE AROUND 940 PM EDT...
  CHESTER AROUND 945 PM EDT...
  OVERTON AND GRASONVILLE AROUND 950 PM EDT...
  TILGHMAN ISLAND AND TALBOT AROUND 955 PM EDT...
  COPPERVILLE...CENTERVILLE...ST. MICHAELS AND CENTREVILLE AROUND
  1000 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DOPPLER RADAR HAS INDICATED SOME WEAK ROTATION WITHIN THIS STORM.
WHILE NOT IMMEDIATELY LIKELY...A TORNADO MAY STILL DEVELOP. IF A
TORNADO IS SPOTTED...ACT QUICKLY AND MOVE TO A PLACE OF SAFETY IN A
STURDY STRUCTURE...SUCH AS A BASEMENT OR SMALL INTERIOR ROOM.

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT
TUESDAY MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY.

&&

LAT...LON 3873 7625 3867 7636 3877 7640 3875 7635
      3887 7625 3882 7621 3883 7620 3894 7624
      3884 7638 3885 7639 3905 7631 3900 7627
      3900 7618 3903 7625 3909 7624 3906 7548
      3869 7581 3867 7595 3857 7602
TIME...MOT...LOC 0133Z 270DEG 30KT 3911 7634 3887 7645
          3848 7679

$$

MPD
1 follow-up statement
112 
WWUS51 KPHI 120207
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1007 PM EDT MON JUL 11 2011

DEC001-MDC011-029-035-041-120230-
/O.CON.KPHI.SV.W.0173.000000T0000Z-110712T0230Z/
KENT DE-CAROLINE MD-KENT MD-QUEEN ANNE'S MD-TALBOT MD-
1007 PM EDT MON JUL 11 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1030 PM EDT
FOR TALBOT...SOUTHERN QUEEN ANNE'S...EXTREME SOUTHWESTERN KENT...
CAROLINE AND SOUTHWESTERN KENT COUNTIES...

AT 1002 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING
WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE
EXTENDING FROM CARVILLE TO COPPERVILLE TO 20 MILES SOUTHWEST OF 
TILGHMAN ISLAND...OR ALONG A LINE EXTENDING FROM CENTERVILLE TO 
ABOUT 10 MILES NORTHWEST OF EASTON TO 30 MILES SOUTHWEST OF 
EASTON...MOVING EAST AT 35 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  CORDOVA...QUEEN ANNE...OXFORD AND EASTON BY 1015 PM EDT...
  JUMPTOWN...OAKLAND...RIDGELY AND HILLSBORO BY 1020 PM EDT...
  TANYARD AND MATTHEWS BY 1025 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO WINDS...CONTINUOUS CLOUD TO GROUND LIGHTNING IS 
OCCURRING WITH THIS STORM. MOVE INDOORS IMMEDIATELY! LIGHTNING IS 
ONE OF NATURES NUMBER ONE 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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL MIDNIGHT EDT
TUESDAY MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY.

&&

LAT...LON 3873 7625 3867 7636 3877 7640 3875 7635
      3887 7625 3882 7621 3883 7620 3894 7624
      3884 7638 3885 7639 3905 7631 3900 7627
      3900 7618 3903 7625 3909 7624 3906 7548
      3869 7581 3867 7595 3857 7602
TIME...MOT...LOC 0207Z 270DEG 30KT 3911 7597 3887 7609
          3848 7643

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 9:11 PM EDTSevere Thunderstorm WarningPHICecil, Kent, Queen Anne's64 min
Jul 11, 9:25 PM EDTSpecial Weather StatementPHIQueen Anne's, Talbot65 min
Jul 11, 10:28 PM EDTSevere Thunderstorm WarningPHICaroline, Talbot33 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2011Severe 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.