Alert archive / Maryland / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 200, NWS Philadelphia/Mount Holly

August 17, 2012Cecil County, Kent County, Queen Anne's County, Maryland; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 17, 2012, 9:08 PM EDT for Cecil County, Kent County, Queen Anne's County, Maryland; New Castle County, Delaware. It was in force for 67 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 17, 2012, 9:08 PM EDT (01:08 UTC)
Expired
Aug 17, 2012, 10:15 PM EDT
In force
67 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), 79 km from the middle of the area, began a volume at 01:10 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 00:00Z, 1.1 hours before the alert went out and 94 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 2012-08-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 288 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2012-08-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 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
288 J/kg
Mixed-layer CIN
-73 J/kg
Mixed-layer LCL
1300 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
44 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

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

571 
WUUS51 KPHI 180108
SVRPHI
DEC003-MDC015-029-035-180215-
/O.NEW.KPHI.SV.W.0200.120818T0108Z-120818T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
908 PM EDT FRI AUG 17 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN CECIL COUNTY IN NORTHEAST MARYLAND...
  KENT COUNTY IN NORTHEAST MARYLAND...
  NORTHERN QUEEN ANNE'S COUNTY IN NORTHEAST MARYLAND...
  SOUTHERN NEW CASTLE COUNTY IN NORTHERN DELAWARE...

* UNTIL 1015 PM EDT

* AT 906 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM CHARLESTOWN TO STEVENSVILLE...
  OR ALONG A LINE EXTENDING FROM 17 MILES SOUTHWEST OF NEWARK TO 24
  MILES SOUTHEAST OF BALTIMORE...AND MOVING EAST AT 20 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  CHARLESTOWN AND BETTERTON AROUND 915 PM EDT...
  OVERTON AROUND 920 PM EDT...
  NORTH EAST AND LANGFORD AROUND 925 PM EDT...
  OLD TOWN...HOLLYWOOD BEACH AND CHESTERTOWN AROUND 935 PM EDT...
  KENNEDYVILLE AROUND 940 PM EDT...
  ELKTON AROUND 945 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND 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.

HEAVY RAIN WILL OCCUR WITH THESE STORMS AND CAUSE LOW-LYING AND 
POOR DRAINAGE FLOODING.

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.

&&

LAT...LON 3904 7632 3902 7627 3905 7624 3917 7629
      3932 7619 3943 7600 3952 7599 3954 7607
      3960 7608 3971 7552 3962 7560 3960 7560
      3964 7557 3958 7555 3929 7576 3908 7586
      3900 7622 3903 7626 3898 7634
TIME...MOT...LOC 0108Z 255DEG 15KT 3954 7601 3906 7629

$$

GSS/MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 8:24 PM EDTSpecial Weather StatementPHICecil, Kent81 min
Aug 17, 9:31 PM EDTSpecial Weather StatementPHICaroline, Queen Anne's89 min
Aug 17, 9:55 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's, Talbot65 min
Aug 17, 10:55 PM EDTSpecial Weather StatementPHICaroline, Talbot65 min
Aug 17, 11:39 PM EDTSpecial Weather StatementPHISussex81 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2012Severe Thunderstorm Warnings in Delaware, 2012Every severe thunderstorm warning in 2012

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.