Alert archive / Maryland / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 110, NWS Philadelphia/Mount Holly

August 11, 20154 counties in Maryland; Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 11, 2015, 4:18 PM EDT for 4 counties in Maryland; Kent County, New Castle 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
Aug 11, 2015, 4:18 PM EDT (20:18 UTC)
Expired
Aug 11, 2015, 5:15 PM EDT
In force
57 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

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

The radar

The Dover AFB radar (KDOX), 48 km from the middle of the area, began a volume at 20:20 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 8.3 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2015-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 16 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 12:00Z on 2015-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 square meters per square second.19395878Sfc1 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
16 J/kg
Mixed-layer CIN
-19 J/kg
Mixed-layer LCL
669 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
60 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

222 
WUUS51 KPHI 112018
SVRPHI
DEC001-003-MDC011-029-035-041-112115-
/O.NEW.KPHI.SV.W.0110.150811T2018Z-150811T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
418 PM EDT TUE AUG 11 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...
  KENT COUNTY IN CENTRAL DELAWARE...
  SOUTHWESTERN KENT COUNTY IN NORTHEASTERN MARYLAND...
  QUEEN ANNE'S COUNTY IN NORTHEASTERN MARYLAND...
  CAROLINE COUNTY IN EASTERN MARYLAND...
  NORTHEASTERN TALBOT COUNTY IN EASTERN MARYLAND...

* UNTIL 515 PM EDT

* AT 417 PM EDT...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
  MILLINGTON TO NEAR SUDLERSVILLE TO NEAR CENTREVILLE...AND MOVING
  SOUTHEAST AT 20 MPH.

* LOCATIONS IMPACTED INCLUDE...
  DOVER...CENTERVILLE...SMYRNA...DENTON...CENTREVILLE...CAMDEN...
  CLAYTON...GREENSBORO...OAKLAND...RIDGELY...CHESWOLD...CHURCH
  HILL...MILLINGTON...SUDLERSVILLE...GOLDSBORO...QUEEN ANNE...
  WOODSIDE...VIOLA...HARTLY AND HARMONY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...DEADLY
LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION...MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

IN ADDITION TO DAMAGING WINDS...FREQUENT CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY. REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE
ENOUGH TO BE STRUCK BY LIGHTNING.

&&

LAT...LON 3898 7620 3900 7617 3902 7619 3918 7598
      3935 7584 3924 7540 3914 7541 3901 7552
      3875 7585 3897 7623
TIME...MOT...LOC 2017Z 296DEG 16KT 3927 7582 3916 7591 3900 7611 

$$
2 follow-up statements
220 
WWUS51 KPHI 112043
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
443 PM EDT TUE AUG 11 2015

DEC003-MDC029-112052-
/O.CAN.KPHI.SV.W.0110.000000T0000Z-150811T2115Z/
NEW CASTLE DE-KENT MD-
443 PM EDT TUE AUG 11 2015

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN NEW CASTLE AND
SOUTHWESTERN KENT COUNTIES IS CANCELLED...

THE STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE WARNED 
AREA. THEREFORE THE WARNING HAS BEEN CANCELLED.

LAT...LON 3902 7608 3909 7599 3903 7589 3912 7579
      3928 7565 3924 7540 3914 7541 3901 7552
      3875 7585 3895 7618
TIME...MOT...LOC 2042Z 296DEG 16KT 3923 7570 3912 7579 3896 7599 

$$

DEC001-MDC011-035-041-112115-
/O.CON.KPHI.SV.W.0110.000000T0000Z-150811T2115Z/
KENT DE-QUEEN ANNE'S MD-CAROLINE MD-TALBOT MD-
443 PM EDT TUE AUG 11 2015

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR NORTHWESTERN KENT...SOUTHEASTERN QUEEN ANNE'S...CAROLINE AND
NORTHEASTERN TALBOT COUNTIES...

AT 442 PM EDT...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 NEAR
HARTLY TO NEAR GOLDSBORO TO STARR...MOVING SOUTHEAST AT 20 MPH.

LOCATIONS IMPACTED INCLUDE...
DOVER...DENTON...CAMDEN...GREENSBORO...OAKLAND...RIDGELY...
CHESWOLD...GOLDSBORO...QUEEN ANNE...WOODSIDE...VIOLA...HARTLY...
STARR...HARMONY...HOPE...RISING SUN...CORDOVA...HAZLETTVILLE...DOVER
SPEEDWAY AND JUMPTOWN.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SEVERE THUNDERSTORMS PRODUCE DAMAGING WINDS...LARGE HAIL...DEADLY
LIGHTNING AND VERY HEAVY RAIN. FOR YOUR PROTECTION MOVE TO AN
INTERIOR ROOM ON THE LOWEST FLOOR OF YOUR HOME OR BUSINESS. HEAVY
RAINS FLOOD ROADS QUICKLY SO DO NOT DRIVE INTO AREAS WHERE WATER
COVERS THE ROAD.

&&

LAT...LON 3902 7608 3909 7599 3903 7589 3912 7579
      3928 7565 3924 7540 3914 7541 3901 7552
      3875 7585 3895 7618
TIME...MOT...LOC 2042Z 296DEG 16KT 3923 7570 3912 7579 3896 7599 

$$

PO
039 
WWUS51 KPHI 112114
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
514 PM EDT TUE AUG 11 2015

DEC001-MDC011-035-041-112123-
/O.EXP.KPHI.SV.W.0110.000000T0000Z-150811T2115Z/
KENT DE-QUEEN ANNE'S MD-CAROLINE MD-TALBOT MD-
514 PM EDT TUE AUG 11 2015

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN KENT...
SOUTHEASTERN QUEEN ANNE'S...CAROLINE AND NORTHEASTERN TALBOT COUNTIES
WILL EXPIRE AT 515 PM EDT...

THE STORMS WHICH PROMPTED THE WARNING HAS WEAKENED. 
THEREFORE THE WARNING WILL BE ALLOWED TO EXPIRE. CLOUD TO
GROUND LIGHTNING IS STILL OCCURRING IN KENT COUNTY.

LAT...LON 3902 7608 3909 7599 3903 7589 3912 7579
      3928 7565 3924 7540 3914 7541 3901 7552
      3875 7585 3895 7618
TIME...MOT...LOC 2111Z 296DEG 16KT 3923 7570 3912 7579 3896 7599 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 2:54 PM EDTSpecial Weather StatementPHICecil66 min
Aug 11, 3:30 PM EDTSpecial Weather StatementPHICaroline, Cecil, Kent, Queen Anne's60 min
Aug 11, 4:32 PM EDTSpecial Weather StatementPHITalbot88 min
Aug 11, 3:44 AM EDTAreal Flood AdvisoryPHINew Castle4 hr
Aug 11, 5:12 PM EDTSpecial Weather StatementPHISussex93 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2015Severe Thunderstorm Warnings in Delaware, 2015Every severe thunderstorm warning in 2015

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.