Alert archive / Maryland / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 172, NWS Philadelphia/Mount Holly

July 11, 2011New Castle County, Delaware; Cecil County, Kent County, Queen Anne's County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 11, 2011, 9:11 PM EDT for New Castle County, Delaware; Cecil County, Kent County, Queen Anne's County, Maryland. It was in force for 64 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, 9:11 PM EDT (01:11 UTC)
Expired
Jul 11, 2011, 10:15 PM EDT
In force
64 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

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

The radar

The Dover AFB radar (KDOX), 74 km from the middle of the area, began a volume at 01:11 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, 1.2 hours before the alert went out and 140 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.

911 
WUUS51 KPHI 120111
SVRPHI
DEC003-MDC015-029-035-120215-
/O.NEW.KPHI.SV.W.0172.110712T0111Z-110712T0215Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  CECIL COUNTY IN NORTHEAST MARYLAND...
  THIS INCLUDES THE CITY OF ELKTON...
  KENT COUNTY IN NORTHEAST MARYLAND...
  NORTHEASTERN QUEEN ANNE'S COUNTY IN NORTHEAST MARYLAND...
  NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  THIS INCLUDES THE CITIES OF...WILMINGTON...NEWARK...MIDDLETOWN...

* UNTIL 1015 PM EDT

* AT 907 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 CONOWINGO TO 17 MILES WEST OF ROCK HALL...OR ALONG A LINE
  EXTENDING FROM 20 MILES WEST OF ELKTON TO 11 MILES SOUTH OF
  BALTIMORE...AND MOVING EAST AT 35 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  FARMINGTON AND WOODLAWN AROUND 920 PM EDT...
  ZION AND CALVERT AROUND 925 PM EDT...
  PLEASANT HILL...BLAKE...LOMBARD AND BAY VIEW AROUND 930 PM EDT...
  ANDORA AND FAIR HILL AROUND 935 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 3918 7628 3934 7618 3938 7607 3942 7602
      3951 7599 3953 7600 3956 7610 3972 7624
      3974 7547 3962 7560 3959 7559 3960 7555
      3946 7558 3941 7552 3931 7560 3929 7576
      3914 7575 3912 7583 3906 7587 3907 7623
TIME...MOT...LOC 0111Z 271DEG 30KT 3967 7613 3915 7652

$$

MPD
2 follow-up statements
151 
WWUS51 KPHI 120140
SVSPHI

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

DEC003-MDC015-029-035-120215-
/O.CON.KPHI.SV.W.0172.000000T0000Z-110712T0215Z/
CECIL MD-KENT MD-QUEEN ANNE'S MD-NEW CASTLE DE-
940 PM EDT MON JUL 11 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM EDT
FOR NEW CASTLE...NORTHEASTERN QUEEN ANNE'S...KENT AND CECIL
COUNTIES...

AT 939 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 FAIR HILL TO ROCK HALL...MOVING EAST AT 35 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  OLD TOWN...KENNEDYVILLE...BRANTWOOD AND ELKTON BY 945 PM EDT...
  PIKE CREEK...MORGNEC...CAYOTS AND GLASGOW BY 950 PM EDT...
  STANTON AND NEWPORT BY 955 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE 
IMMEDIATELY FOR DAMAGING WINDS...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 MIDNIGHT EDT
TUESDAY MORNING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY.

&&

LAT...LON 3934 7618 3942 7602 3951 7599 3953 7600
      3956 7610 3964 7616 3972 7605 3974 7547
      3962 7560 3959 7559 3959 7555 3946 7558
      3941 7552 3931 7560 3929 7576 3914 7575
      3912 7584 3906 7587 3907 7623 3918 7628
TIME...MOT...LOC 0139Z 277DEG 29KT 3969 7580 3908 7624

$$

IOVINO
901 
WWUS51 KPHI 120202
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1002 PM EDT MON JUL 11 2011

MDC015-120211-
/O.CAN.KPHI.SV.W.0172.000000T0000Z-110712T0215Z/
CECIL MD-
1002 PM EDT MON JUL 11 2011

...THE SEVERE THUNDERSTORM WARNING FOR CECIL COUNTY IS CANCELLED...

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 3932 7619 3938 7611 3937 7584 3938 7585
      3938 7577 3940 7577 3940 7553 3931 7560
      3929 7576 3914 7575 3914 7579 3912 7584
      3906 7587 3907 7623 3918 7628
TIME...MOT...LOC 0201Z 277DEG 29KT 3943 7573 3923 7610

$$

DEC003-MDC029-035-120215-
/O.CON.KPHI.SV.W.0172.000000T0000Z-110712T0215Z/
KENT MD-QUEEN ANNE'S MD-NEW CASTLE DE-
1002 PM EDT MON JUL 11 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1015 PM EDT
FOR SOUTHERN NEW CASTLE...NORTHEASTERN QUEEN ANNE'S AND KENT
COUNTIES...

AT 957 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 SASSAFRAS TO LANGFORD...OR ALONG A LINE EXTENDING FROM
MIDDLETOWN TO ABOUT 15 MILES NORTH OF CENTERVILLE...MOVING EAST AT 
35 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  STARKEY CORNER...MASSEY...CRUMPTON AND CHURCH HILL BY 1010 PM
  EDT...
  MILLINGTON...CHAMBERSVILLE...GREEN SPRING AND SUDLERSVILLE BY 1015
  PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO HAIL AND WINDS...CONTINUOUS CLOUD TO GROUND LIGHTNING 
IS OCCURRING WITH THESE STORMS. 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 3932 7619 3938 7611 3937 7584 3938 7585
      3938 7577 3940 7577 3940 7553 3931 7560
      3929 7576 3914 7575 3914 7579 3912 7584
      3906 7587 3907 7623 3918 7628
TIME...MOT...LOC 0201Z 277DEG 29KT 3943 7573 3923 7610

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 11, 9:33 PM EDTSevere Thunderstorm WarningPHIKent57 min
Jul 11, 10:28 PM EDTSevere Thunderstorm WarningPHIKent, Sussex33 min
Jul 11, 9:25 PM EDTSpecial Weather StatementPHIQueen Anne's, Talbot65 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.