Alert archive / Maryland / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 34, NWS Philadelphia/Mount Holly

April 28, 20114 counties in Maryland; Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 28, 2011, 11:37 AM EDT for 4 counties in Maryland; Kent County, New Castle County, Delaware. It was in force for 53 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: Apr 28, 2011, 11:37 AM EDT (15:37 UTC)
Expired: Apr 28, 2011, 12:30 PM EDT
In force: 53 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Kent County, DE, New Castle County, DE, Caroline County, MD, Cecil County, MD, Kent County, MD, Queen Anne's County, MD

The radar

The Dover AFB radar (KDOX), 68 km from the middle of the area, began a volume at 15:38 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
Apr 28, 9:45 AM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 3.6 hours before the alert went out and 34 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: 482 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 670 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 371 m²/s²
0-3 km storm-relative helicity: 401 m²/s²
Significant tornado parameter: 1.3
Supercell composite: 5.5

Open this sounding in Storm Lab

The text

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

418 
WUUS51 KPHI 281537
SVRPHI
DEC001-003-MDC011-015-029-035-281630-
/O.NEW.KPHI.SV.W.0034.110428T1537Z-110428T1630Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1137 AM EDT THU APR 28 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHERN KENT COUNTY IN CENTRAL DELAWARE...
  NORTH CENTRAL CAROLINE COUNTY IN EASTERN MARYLAND...
  SOUTHEASTERN CECIL COUNTY IN NORTHEAST MARYLAND...
  KENT COUNTY IN NORTHEAST MARYLAND...
  NORTHERN QUEEN ANNE'S COUNTY IN NORTHEAST MARYLAND...
  THIS INCLUDES THE CITY OF CENTERVILLE...
  SOUTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITY OF MIDDLETOWN...

* UNTIL 1230 PM EDT

* AT 1133 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR STEVENSVILLE...OR 13 MILES
  WEST OF CENTERVILLE...AND MOVING NORTHEAST AT 50 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  OLD TOWN...CENTREVILLE AND CENTERVILLE AROUND 1150 AM EDT...
  CHURCH HILL AND STARKEY CORNER AROUND 1155 AM EDT...
  SUDLERSVILLE AND CRUMPTON AROUND 1205 PM EDT...
  MILLINGTON AROUND 1210 PM EDT...
  DELANEY CORNER AND HARTLY AROUND 1215 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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON 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 3916 7628 3934 7618
      3938 7611 3938 7607 3941 7605 3954 7563
      3924 7538 3921 7538 3893 7633 3898 7636
TIME...MOT...LOC 1537Z 245DEG 42KT 3906 7625

$$

HEAVENER

2 follow-up statements

097 
WWUS51 KPHI 281612
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1212 PM EDT THU APR 28 2011

MDC011-281622-
/O.CAN.KPHI.SV.W.0034.000000T0000Z-110428T1630Z/
CAROLINE MD-
1212 PM EDT THU APR 28 2011

...THE SEVERE THUNDERSTORM WARNING FOR NORTH CENTRAL CAROLINE COUNTY
IS CANCELLED...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 3921 7538 3914 7589 3941 7605 3954 7563
      3924 7538
TIME...MOT...LOC 1612Z 245DEG 42KT 3923 7577

$$

DEC001-003-MDC015-029-035-281630-
/O.CON.KPHI.SV.W.0034.000000T0000Z-110428T1630Z/
KENT DE-CECIL MD-KENT MD-QUEEN ANNE'S MD-NEW CASTLE DE-
1212 PM EDT THU APR 28 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1230 PM EDT
FOR SOUTHERN NEW CASTLE...NORTHEASTERN QUEEN ANNE'S...NORTHEASTERN
KENT...SOUTHEASTERN CECIL AND NORTHERN KENT COUNTIES...

AT 1211 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN
EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR MILLINGTON...OR 15
MILES WEST OF DOVER...MOVING NORTHEAST AT 50 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  CLAYTON...KENTON AND GREEN SPRING BY 1220 PM EDT...
  SMYRNA...CHAMBERSVILLE...LEIPSIC AND CHESWOLD BY 1225 PM EDT...
  WOODLAND BEACH BY 1230 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 3921 7538 3914 7589 3941 7605 3954 7563
      3924 7538
TIME...MOT...LOC 1612Z 245DEG 42KT 3923 7577

$$

HEAVENER

288 
WWUS51 KPHI 281627
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1227 PM EDT THU APR 28 2011

DEC001-003-MDC015-029-035-281637-
/O.EXP.KPHI.SV.W.0034.000000T0000Z-110428T1630Z/
KENT DE-CECIL MD-KENT MD-QUEEN ANNE'S MD-NEW CASTLE DE-
1227 PM EDT THU APR 28 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN NEW CASTLE...
NORTHEASTERN QUEEN ANNE'S...NORTHEASTERN KENT...SOUTHEASTERN CECIL
AND NORTHERN KENT COUNTIES WILL EXPIRE AT 1230 PM EDT...

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 400 PM EDT
THURSDAY AFTERNOON FOR DELAWARE AND NORTHEASTERN MARYLAND AND NEW
JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 3921 7538 3914 7589 3941 7605 3954 7563
      3924 7538
TIME...MOT...LOC 1627Z 245DEG 42KT 3930 7556

$$

HEAVENER

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 28, 6:12 AM EDT	Special Weather Statement	PHI	Cecil, Kent	63 min
Apr 28, 9:55 AM EDT	River Flood Warning	PHI	Cecil, Harford	66 hr
Apr 28, 11:32 AM EDT	Special Weather Statement	PHI	Caroline, Queen Anne's, Talbot	58 min
Apr 28, 12:42 PM EDT	Special Weather Statement	PHI	Cecil, Kent, Queen Anne's	63 min
Apr 28, 5:04 PM EDT	Special Weather Statement	PHI	Caroline, Talbot	56 min
Apr 28, 5:38 PM EDT	Severe Thunderstorm Warning	PHI	Caroline	39 min
Apr 28, 6:56 AM EDT	Severe Thunderstorm Warning	PHI	New Castle	34 min
Apr 28, 12:34 PM EDT	Special Weather Statement	PHI	Kent	56 min
Apr 28, 1:13 PM EDT	Special Weather Statement	PHI	Sussex	62 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2011 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.