Alert archive / Maryland / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 286, NWS Philadelphia/Mount Holly

August 21, 2011Kent County, Queen Anne's County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 21, 2011, 2:55 PM EDT for Kent County, Queen Anne's County, Talbot County, Maryland. It was in force for 65 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 21, 2011, 2:55 PM EDT (18:55 UTC)
Expired: Aug 21, 2011, 4:00 PM EDT
In force: 65 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

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

The radar

The Dover AFB radar (KDOX), 71 km from the middle of the area, began a volume at 18:56 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.

Issued	Product	Office	Lasted
Aug 21, 12:52 PM EDT	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.9 hours before the alert went out and 103 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: 1589 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 969 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: 131 m²/s²
0-3 km storm-relative helicity: 125 m²/s²
Significant tornado parameter: 0.6
Supercell composite: 4.9

Open this sounding in Storm Lab

The text

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

576 
WUUS51 KPHI 211855
SVRPHI
MDC029-035-041-212000-
/O.NEW.KPHI.SV.W.0286.110821T1855Z-110821T2000Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
255 PM EDT SUN AUG 21 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 400 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
  ROCK HALL...AND MOVING SOUTHEAST AT 15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  ROCK HALL AROUND 300 PM EDT...
  OVERTON AROUND 325 PM EDT...
  OLD TOWN AROUND 330 PM EDT...
  CENTERVILLE AROUND 355 PM EDT...
  CARVILLE...STARR...HOPE AND WYE MILLS AROUND 400 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.

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

&&

LAT...LON 3905 7631 3900 7627 3898 7621 3900 7618
      3903 7625 3910 7624 3914 7626 3915 7628
      3931 7619 3923 7579 3882 7605 3890 7622
      3893 7621 3894 7624 3892 7623 3898 7636
TIME...MOT...LOC 1855Z 297DEG 12KT 3912 7629

$$

IOVINO

1 follow-up statement

925 
WWUS51 KPHI 211936
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
336 PM EDT SUN AUG 21 2011

MDC029-035-041-212000-
/O.CON.KPHI.SV.W.0286.000000T0000Z-110821T2000Z/
KENT MD-QUEEN ANNE'S MD-TALBOT MD-
336 PM EDT SUN AUG 21 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT
FOR NORTH CENTRAL TALBOT...QUEEN ANNE'S AND SOUTHERN KENT COUNTIES...

AT 334 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS 
LOCATED NEAR OVERTON AND CENTERVILLE...MOVING SOUTHEAST AT 15 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  STARKEY CORNER BY 350 PM EDT...
  CHURCH HILL BY 355 PM EDT...
  CARVILLE...STARR...HOPE AND WYE MILLS BY 400 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.

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 900 PM EDT SUNDAY
EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW JERSEY AND
EASTERN PENNSYLVANIA.

&&

LAT...LON 3905 7631 3900 7627 3898 7621 3900 7618
      3903 7625 3910 7624 3914 7626 3915 7628
      3931 7619 3923 7579 3882 7605 3890 7622
      3893 7621 3894 7624 3892 7623 3898 7636
TIME...MOT...LOC 1936Z 297DEG 12KT 3906 7613

$$

IOVINO

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 3:28 AM EDT	Flash Flood Watch	PHI	Cecil, Kent	17 hr
Aug 21, 8:01 AM EDT	Special Weather Statement	PHI	Cecil, Kent	59 min
Aug 21, 9:08 AM EDT	Special Weather Statement	PHI	Cecil, Kent	52 min
Aug 21, 9:36 AM EDT	Areal Flood Advisory	PHI	Cecil, Kent, Queen Anne's	2 hr
Aug 21, 2:01 PM EDT	Severe Thunderstorm Warning	PHI	Cecil, Kent, Queen Anne's	59 min
Aug 21, 2:43 PM EDT	Areal Flood Advisory	PHI	Cecil, Kent, Queen Anne's	3 hr
Aug 21, 3:11 PM EDT	Areal Flood Advisory	PHI	Kent, Queen Anne's	2 hr
Aug 21, 4:03 PM EDT	Special Weather Statement	PHI	Caroline, Kent, Queen Anne's, Talbot	57 min
Aug 21, 4:45 PM EDT	Flash Flood Warning	PHI	Kent	3 hr
Aug 21, 5:09 PM EDT	Severe Thunderstorm Warning	PHI	Caroline, Kent, Queen Anne's, Talbot	37 min
Aug 21, 5:20 PM EDT	Areal Flood Advisory	PHI	Caroline, Queen Anne's, Talbot	115 min
Aug 21, 7:17 PM EDT	Areal Flood Advisory	PHI	Caroline	118 min

Nearby

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.