Alert archive / Delaware / Severe Thunderstorm Warnings in 2012

Severe Thunderstorm Warning 189, NWS Philadelphia/Mount Holly

August 10, 2012Kent County, Sussex County, Delaware; Caroline County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 10, 2012, 8:55 AM EDT for Kent County, Sussex County, Delaware; Caroline County, Talbot County, Maryland. It was in force for 65 min. 1 report 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
Aug 10, 2012, 8:55 AM EDT (12:55 UTC)
Expired
Aug 10, 2012, 10:00 AM EDT
In force
65 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Kent County, DE, Sussex County, DE, Caroline County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 43 km from the middle of the area, began a volume at 12:57 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

TimeReportWhereRemark
Aug 10, 9:30 AM EDTTSTM WND DMGGreensboro, MDTREES DOWN

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

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 0.9 hours before the alert went out and 96 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, Wallops Is Stn, VA at 12:00Z on 2012-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1273 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, Wallops Is Stn, VA at 12:00Z on 2012-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 43 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
1273 J/kg
Mixed-layer CIN
-9 J/kg
Mixed-layer LCL
653 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
43 m²/s²
0-3 km storm-relative helicity
61 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.7

Open this sounding in Storm Lab

The text

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

484 
WUUS51 KPHI 101255
SVRPHI
DEC001-005-MDC011-041-101400-
/O.NEW.KPHI.SV.W.0189.120810T1255Z-120810T1400Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
855 AM EDT FRI AUG 10 2012

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN KENT COUNTY IN CENTRAL DELAWARE...
  WESTERN SUSSEX COUNTY IN CENTRAL DELAWARE...
  CAROLINE COUNTY IN EASTERN MARYLAND...
  TALBOT COUNTY IN EASTERN MARYLAND...

* UNTIL 1000 AM EDT

* AT 853 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED AN
  AREA OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING DAMAGING WINDS IN
  EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING
  FROM TANYARD TO 20 MILES SOUTH OF TRAPPE...OR ALONG A LINE
  EXTENDING FROM 34 MILES WEST OF GEORGETOWN TO 44 MILES SOUTHWEST OF
  GEORGETOWN...AND MOVING NORTHEAST AT 40 MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  WINDYHILL AND TANYARD AROUND 900 AM EDT...
  MATTHEWS AND CHOPTANK AROUND 905 AM EDT...
  GRIFFIN...HARMONY AND PRESTON AROUND 910 AM EDT...
  RIDGELY AND DENTON AROUND 915 AM EDT...
  GREENSBORO AROUND 925 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

IN ADDITION TO DAMAGING WINDS...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 3846 7570 3864 7571 3868 7576 3867 7580
      3870 7581 3867 7594 3860 7598 3857 7603
      3860 7608 3860 7613 3866 7618 3867 7621
      3884 7620 3893 7600 3892 7596 3896 7594
      3914 7554 3845 7558
TIME...MOT...LOC 1254Z 227DEG 33KT 3875 7602 3837 7609

$$

MPD
3 follow-up statements
431 
WWUS51 KPHI 101322
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
922 AM EDT FRI AUG 10 2012

DEC001-005-MDC011-041-101400-
/O.CON.KPHI.SV.W.0189.000000T0000Z-120810T1400Z/
KENT DE-TALBOT MD-CAROLINE MD-SUSSEX DE-
922 AM EDT FRI AUG 10 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 AM EDT
FOR WESTERN SUSSEX...CAROLINE...EASTERN TALBOT AND SOUTHWESTERN KENT
COUNTIES...

AT 917 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE AN AREA OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING 
DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE LOCATED FROM 
NEAR HILLSBORO TO ABOUT 10 MILES SOUTHWEST OF BETHEL...OR FROM ABOUT 
30 MILES SOUTHWEST OF DOVER TO 25 MILES SOUTHWEST OF GEORGETOWN...
MOVING NORTHEAST AT 30 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  SMITHVILLE AND GREENSBORO BY 930 AM EDT...
  SEAFORD...LAUREL...BLADES AND BETHEL BY 935 AM EDT...
  SANDTOWN...ANDREWSVILLE AND BRIDGEVILLE BY 940 AM EDT...
  GREENWOOD BY 945 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

IN ADDITION TO DAMAGING WINDS...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 3846 7570 3864 7571 3868 7576 3867 7580
      3870 7581 3870 7584 3867 7594 3863 7596
      3863 7598 3873 7599 3889 7609 3893 7600
      3892 7596 3896 7594 3914 7554 3845 7558
TIME...MOT...LOC 1321Z 227DEG 33KT 3892 7589 3851 7574

$$

MPD
407 
WWUS51 KPHI 101333
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
933 AM EDT FRI AUG 10 2012

MDC041-101342-
/O.CAN.KPHI.SV.W.0189.000000T0000Z-120810T1400Z/
TALBOT MD-
933 AM EDT FRI AUG 10 2012

...THE SEVERE THUNDERSTORM WARNING FOR EASTERN TALBOT 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.

LAT...LON 3846 7570 3864 7571 3868 7576 3867 7580
      3870 7581 3867 7595 3870 7599 3874 7600
      3878 7597 3881 7590 3888 7595 3896 7594
      3914 7554 3845 7558
TIME...MOT...LOC 1332Z 227DEG 33KT 3899 7579 3885 7581
          3858 7565

$$

DEC001-005-MDC011-101400-
/O.CON.KPHI.SV.W.0189.000000T0000Z-120810T1400Z/
KENT DE-CAROLINE MD-SUSSEX DE-
933 AM EDT FRI AUG 10 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 AM EDT
FOR WESTERN SUSSEX...CAROLINE AND SOUTHWESTERN KENT COUNTIES...

AT 927 AM EDT...AN AREA OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING 
DAMAGING WINDS IN EXCESS OF 60 MPH WERE LOCATED FROM GREENSBORO TO 
HARMONY TO BETHEL...OR FROM ABOUT 20 MILES SOUTHWEST OF DOVER TO 
ABOUT 25 MILES WEST OF GEORGETOWN TO ABOUT 20 MILES SOUTHWEST OF 
GEORGETOWN...MOVING NORTHEAST AT 35 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  SANDTOWN...SEAFORD AND BLADES BY 940 AM EDT...
  ANDREWSVILLE AND BRIDGEVILLE BY 945 AM EDT...
  GREENWOOD AND FARMINGTON BY 950 AM EDT...
  WYOMING...WOODSIDE AND VIOLA BY 955 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

IN ADDITION TO DAMAGING WINDS...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 3846 7570 3864 7571 3868 7576 3867 7580
      3870 7581 3867 7595 3870 7599 3874 7600
      3878 7597 3881 7590 3888 7595 3896 7594
      3914 7554 3845 7558
TIME...MOT...LOC 1332Z 227DEG 33KT 3899 7579 3885 7581
          3858 7565

$$

MPD
172 
WWUS51 KPHI 101354
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
954 AM EDT FRI AUG 10 2012

MDC011-101402-
/O.CAN.KPHI.SV.W.0189.000000T0000Z-120810T1400Z/
CAROLINE MD-
954 AM EDT FRI AUG 10 2012

...THE SEVERE THUNDERSTORM WARNING FOR CAROLINE 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.

LAT...LON 3846 7570 3905 7574 3914 7554 3845 7558
TIME...MOT...LOC 1352Z 227DEG 33KT 3911 7562 3897 7564
          3870 7548

$$

DEC001-005-101400-
/O.CON.KPHI.SV.W.0189.000000T0000Z-120810T1400Z/
KENT DE-SUSSEX DE-
954 AM EDT FRI AUG 10 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 AM EDT
FOR WESTERN SUSSEX AND SOUTHWESTERN KENT COUNTIES...

AT 947 AM EDT...THUNDERSTORMS WERE LOCATED FROM SANDTOWN TO 5 MILES 
WEST OF HARRINGTON TO BLADES...OR FROM 10 MILES SOUTHWEST OF DOVER 
TO 5 MILES WEST OF GEORGETOWN...MOVING NORTHEAST AT 35 MPH.

THUNDERSTORMS WILL BE NEAR...
  CAMDEN BY 1000 AM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THESE STORMS. 
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 3846 7570 3905 7574 3914 7554 3845 7558
TIME...MOT...LOC 1352Z 227DEG 33KT 3911 7562 3897 7564
          3870 7548

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 10, 8:41 AM EDTSpecial Weather StatementPHIKent, New Castle94 min
Aug 10, 8:43 AM EDTSpecial Weather StatementPHIKent, New Castle92 min
Aug 10, 9:08 AM EDTAreal Flood AdvisoryPHIKent, New Castle, Sussex3 hr
Aug 10, 10:05 AM EDTSpecial Weather StatementPHIKent, New Castle, Sussex115 min
Aug 10, 10:14 AM EDTSevere Thunderstorm WarningPHISussex61 min
Aug 10, 10:33 AM EDTAreal Flood AdvisoryPHISussex4 hr
Aug 10, 7:40 AM EDTAreal Flood AdvisoryPHICecil, Kent3 hr

Nearby

Severe Thunderstorm Warnings in Delaware, 2012Severe Thunderstorm Warnings in Maryland, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.