Alert archive / Maryland / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 9, NWS Philadelphia/Mount Holly

April 5, 20114 states

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 5, 2011, 5:01 AM EDT for 4 states. It was in force for 74 min. 2 reports 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: Apr 5, 2011, 5:01 AM EDT (09:01 UTC)
Expired: Apr 5, 2011, 6:15 AM EDT
In force: 74 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, Talbot County, MD, Salem County, NJ, Chester County, PA, Delaware County, PA

The radar

The Dover AFB radar (KDOX), 80 km from the middle of the area, began a volume at 09:02 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
Apr 5, 5:40 AM EDT	TSTM WND DMG	1 Wsw West Chester, PA	SHUTTERS RIPPED FROM HOME. ESTIMATED GUSTS BETWEEN 55 MPH AND 65 MPH.
Apr 5, 6:00 AM EDT	TSTM WND DMG	Willistown, PA	TREE DOWN ON SUGAR-TOWN ROAD

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

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 5, 2:18 AM EDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 9.0 hours before the alert went out and 129 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 4112 m above ground
0-6 km bulk shear: 49 kt
0-1 km storm-relative helicity: 284 m²/s²
0-3 km storm-relative helicity: 328 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.

413 
WUUS51 KPHI 050901
SVRPHI
DEC001-003-MDC011-015-029-035-041-NJC033-PAC029-045-051015-
/O.NEW.KPHI.SV.W.0009.110405T0901Z-110405T1015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
501 AM EDT TUE APR 5 2011

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  NORTHWESTERN KENT COUNTY IN CENTRAL DELAWARE...
  NORTHERN CAROLINE COUNTY IN EASTERN MARYLAND...
  EXTREME NORTH CENTRAL TALBOT COUNTY IN EASTERN MARYLAND...
  CECIL COUNTY IN NORTHEAST MARYLAND...
  THIS INCLUDES THE CITY OF ELKTON...
  KENT COUNTY IN NORTHEAST MARYLAND...
  QUEEN ANNE'S COUNTY IN NORTHEAST MARYLAND...
  THIS INCLUDES THE CITY OF CENTERVILLE...
  NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITIES OF...WILMINGTON...NEWARK...MIDDLETOWN...
  CHESTER COUNTY IN SOUTHEAST PENNSYLVANIA...
  THIS INCLUDES THE CITY OF WEST CHESTER...
  WESTERN DELAWARE COUNTY IN SOUTHEAST PENNSYLVANIA...
  EXTREME WEST CENTRAL SALEM COUNTY IN SOUTHERN NEW JERSEY...

* UNTIL 615 AM EDT

* AT 456 AM 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 LANCASTER TO 21 MILES SOUTH OF BALTIMORE...AND 
  MOVING EAST AT 45 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  ROCK SPRINGS...RICHARDSMERE...OCTORARO AND CONOWINGO AROUND 515 AM
  EDT...
  MOUNT VERNON...HOMEVILLE...GLEN ROY AND WEST NOTTINGHAM AROUND 520
  AM EDT...
  HONEY BROOK AND COCHRANVILLE AROUND 525 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THESE SEVERE THUNDERSTORMS MAY CONTAIN LITTLE OR NO LIGHTNING. DO NOT
WAIT FOR THUNDER BEFORE TAKING COVER. SEEK SHELTER IMMEDIATELY INSIDE
A STURDY STRUCTURE AND STAY AWAY FROM WINDOWS.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING
FOR DELAWARE AND NORTHEASTERN MARYLAND.

&&

LAT...LON 3905 7631 3900 7627 3900 7618 3903 7625
      3916 7628 3934 7618 3944 7600 3953 7599
      3956 7610 3972 7624 3978 7607 4011 7595
      4003 7536 3970 7551 3962 7560 3960 7560
      3966 7552 3892 7574 3892 7637 3893 7637
TIME...MOT...LOC 0900Z 270DEG 37KT 4002 7621 3971 7634
          3945 7652 3901 7668

$$

HAYES

3 follow-up statements

058 
WWUS51 KPHI 050933
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
533 AM EDT TUE APR 5 2011

DEC001-003-MDC011-015-029-035-041-NJC033-PAC029-045-051015-
/O.CON.KPHI.SV.W.0009.000000T0000Z-110405T1015Z/
KENT DE-CAROLINE MD-CECIL MD-KENT MD-SALEM NJ-DELAWARE PA-CHESTER PA-
QUEEN ANNE'S MD-TALBOT MD-NEW CASTLE DE-
533 AM EDT TUE APR 5 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 AM EDT
FOR NEW CASTLE...EXTREME NORTH CENTRAL TALBOT...QUEEN ANNE'S...
CHESTER...WESTERN DELAWARE...EXTREME WEST CENTRAL SALEM...KENT...
CECIL...NORTHERN CAROLINE AND NORTHWESTERN KENT COUNTIES...

AT 530 AM 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 11 MILES WEST OF WEST CHESTER TO 9 MILES NORTHWEST OF 
ELKTON TO 20 MILES SOUTHWEST OF ELKTON TO 13 MILES WEST OF 
CENTERVILLE...MOVING EAST AT 45 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  LIONVILLE...LADENBERG...OLD TOWN AND HOLLYWOOD BEACH BY 540 AM
  EDT...
  EXTON...WYE MILLS...STARKEY CORNER AND MORGNEC BY 545 AM EDT...
  MALVERN AND WESTTOWN BY 550 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING
FOR DELAWARE AND NORTHEASTERN MARYLAND. A SEVERE THUNDERSTORM WATCH
ALSO REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING FOR
NORTHEAST MARYLAND AND NEW JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 3905 7631 3900 7627 3900 7618 3903 7625
      3916 7628 3934 7618 3944 7600 3953 7599
      3956 7610 3972 7624 3978 7607 4011 7595
      4003 7536 3970 7551 3962 7560 3960 7560
      3966 7552 3892 7574 3892 7637 3893 7637
TIME...MOT...LOC 0934Z 270DEG 37KT 4000 7575 3970 7588
          3944 7607 3900 7624

$$

HAYES

065 
WWUS51 KPHI 051000
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
600 AM EDT TUE APR 5 2011

DEC001-003-MDC011-015-029-035-041-NJC033-PAC029-045-051015-
/O.CON.KPHI.SV.W.0009.000000T0000Z-110405T1015Z/
KENT DE-CAROLINE MD-CECIL MD-KENT MD-SALEM NJ-DELAWARE PA-CHESTER PA-
QUEEN ANNE'S MD-TALBOT MD-NEW CASTLE DE-
600 AM EDT TUE APR 5 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 AM EDT
FOR NEW CASTLE...EXTREME NORTH CENTRAL TALBOT...QUEEN ANNE'S...
CHESTER...WESTERN DELAWARE...EXTREME WEST CENTRAL SALEM...KENT...
CECIL...NORTHERN CAROLINE AND NORTHWESTERN KENT COUNTIES...

AT 555 AM EDT...A LINE OF SEVERE THUNDERSTORMS WAS REPORTED CAPABLE
OF PRODUCING DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
LOCATED ALONG A LINE EXTENDING FROM GRADYVILLE TO WILMINGTON MANOR TO
WARWICK TO STARR...OR ALONG A LINE EXTENDING FROM 8 MILES EAST OF
WEST CHESTER TO WILMINGTON TO MIDDLETOWN TO 6 MILES SOUTHEAST OF
CENTERVILLE...MOVING EAST AT 45 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  PORT PENN...DELANEY CORNER...TEMPLEVILLE AND GREENSBORO BY 605 AM
  EDT...
  GREEN SPRING...MARYDEL...HENDERSON AND GREENSBORO BY 610 AM EDT...
  SANDTOWN BY 615 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING
FOR DELAWARE AND NORTHEASTERN MARYLAND. A SEVERE THUNDERSTORM WATCH
ALSO REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING FOR
NORTHEAST MARYLAND AND NEW JERSEY AND EASTERN PENNSYLVANIA.

&&

LAT...LON 3905 7631 3900 7627 3900 7618 3903 7625
      3916 7628 3934 7618 3944 7600 3953 7599
      3956 7610 3972 7624 3978 7607 4011 7595
      4003 7536 3970 7551 3962 7560 3960 7560
      3966 7552 3892 7574 3892 7637 3893 7637
TIME...MOT...LOC 1000Z 270DEG 37KT 3999 7539 3969 7553
          3943 7573 3899 7590

$$

HAYES

789 
WWUS51 KPHI 051011
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
611 AM EDT TUE APR 5 2011

DEC001-003-MDC011-015-029-035-041-NJC033-PAC029-045-051021-
/O.EXP.KPHI.SV.W.0009.000000T0000Z-110405T1015Z/
KENT DE-CAROLINE MD-CECIL MD-KENT MD-SALEM NJ-DELAWARE PA-CHESTER PA-
QUEEN ANNE'S MD-TALBOT MD-NEW CASTLE DE-
611 AM EDT TUE APR 5 2011

...THE SEVERE THUNDERSTORM WARNING FOR NEW CASTLE...EXTREME NORTH
CENTRAL TALBOT...QUEEN ANNE'S...CHESTER...WESTERN DELAWARE...EXTREME
WEST CENTRAL SALEM...KENT...CECIL...NORTHERN CAROLINE AND
NORTHWESTERN KENT COUNTIES WILL EXPIRE AT 615 AM EDT...

THE LINE OF THUNDERSTORMS THAT PROMPTED THE WARNING ARE MOVING OUT 
OF THE AREA.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING
FOR DELAWARE AND NORTHEASTERN MARYLAND. A SEVERE THUNDERSTORM WATCH
ALSO REMAINS IN EFFECT UNTIL 1000 AM EDT TUESDAY MORNING FOR
NORTHEAST MARYLAND AND NEW JERSEY AND EASTERN PENNSYLVANIA.

LAT...LON 3905 7631 3900 7627 3900 7618 3903 7625
      3916 7628 3934 7618 3944 7600 3953 7599
      3956 7610 3972 7624 3978 7607 4011 7595
      4003 7536 3970 7551 3962 7560 3960 7560
      3966 7552 3892 7574 3892 7637 3893 7637
TIME...MOT...LOC 1011Z 270DEG 37KT 3997 7524 3968 7538
          3942 7559 3898 7576

$$

HAYES

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 5, 5:28 AM EDT	Severe Thunderstorm Warning	PHI	Caroline, Queen Anne's, Talbot	62 min
Apr 5, 8:55 AM EDT	Special Weather Statement	PHI	Caroline, Cecil, Kent, Queen Anne's, Talbot	65 min
Apr 5, 9:37 AM EDT	Special Weather Statement	PHI	Caroline, Cecil, Kent, Queen Anne's	53 min
Apr 5, 10:20 AM EDT	Severe Thunderstorm Warning	PHI	Caroline, Talbot	40 min
Apr 5, 3:05 PM EDT	Frost Advisory	PHI	Caroline, Queen Anne's, Talbot	13 hr
Apr 5, 5:58 AM EDT	Special Weather Statement	PHI	Hunterdon, Morris, Somerset, Sussex, Warren	62 min
Apr 5, 6:05 AM EDT	Special Weather Statement	PHI	Atlantic, Burlington, Camden, Gloucester, Monmouth, Ocean and 1 more	55 min
Apr 5, 6:30 AM EDT	Special Weather Statement	PHI	Hunterdon, Mercer, Middlesex, Monmouth, Morris, Somerset and 1 more	60 min
Apr 5, 6:42 AM EDT	Special Weather Statement	PHI	Cape May, Cumberland	63 min
Apr 5, 7:05 AM EDT	Special Weather Statement	PHI	Morris	55 min
Apr 5, 7:07 AM EDT	Special Weather Statement	PHI	Burlington, Middlesex, Monmouth, Ocean	53 min
Apr 5, 10:16 AM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Burlington, Camden, Cumberland, Gloucester, Salem	44 min
Apr 5, 10:30 AM EDT	Special Weather Statement	PHI	Mercer, Middlesex, Monmouth, Morris, Somerset	60 min
Apr 5, 10:35 AM EDT	Special Marine Warning	PHI		55 min
Apr 5, 10:41 AM EDT	Severe Thunderstorm Warning	PHI	Atlantic, Cumberland, Salem	19 min
Apr 5, 10:58 AM EDT	Special Weather Statement	PHI	Atlantic, Burlington, Camden, Cape May, Cumberland, Middlesex and 2 more	92 min
Apr 5, 11:00 AM EDT	Severe Thunderstorm Warning	PHI	Burlington, Monmouth, Ocean	30 min
Apr 5, 11:09 AM EDT	Special Marine Warning	PHI		96 min
Apr 5, 11:45 AM EDT	Special Marine Warning	PHI		60 min
Apr 5, 2:57 PM EDT	Small Craft Advisory	PHI		27 hr
Apr 5, 4:03 AM EDT	Special Weather Statement	PHI	Berks	57 min
Apr 5, 5:23 AM EDT	Severe Thunderstorm Warning	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 1 more	67 min

Nearby

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