Alert archive / Maryland / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 197, NWS Philadelphia/Mount Holly

August 11, 2009Queen Anne's County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 11, 2009, 8:09 PM EDT for Queen Anne's County, Talbot County, Maryland. It was in force for 66 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, 2009, 8:09 PM EDT (00:09 UTC)
Expired
Aug 11, 2009, 9:15 PM EDT
In force
66 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Queen Anne's County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 72 km from the middle of the area, began a volume at 00:09 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, 0.2 hours before the alert went out and 100 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 2009-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1894 joules per kilogram.LCLEL10008507005003002001001 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 2009-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 10 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
1894 J/kg
Mixed-layer CIN
-5 J/kg
Mixed-layer LCL
1195 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
10 m²/s²
0-3 km storm-relative helicity
21 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 120009
SVRPHI
MDC035-041-120115-
/O.NEW.KPHI.SV.W.0197.090812T0009Z-090812T0115Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
809 PM EDT TUE AUG 11 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  TALBOT COUNTY IN EASTERN MARYLAND...
  THIS INCLUDES THE CITY OF EASTON...
  EXTREME SOUTHWESTERN QUEEN ANNES COUNTY IN NORTHEAST MARYLAND...

* UNTIL 915 PM EDT

* AT 806 PM EDT...NATIONAL WEATHER SERVICE RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR
  TILGHMAN ISLAND...OR 16 MILES WEST OF EASTON...AND MOVING EAST
  AT 15 TO 20 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  TILGHMAN ISLAND AROUND 815 PM EDT...
  TALBOT AROUND 820 PM EDT...
  ST. MICHAELS AROUND 830 PM EDT...
  COPPERVILLE AROUND 835 PM EDT...
  OXFORD AROUND 845 PM EDT...
  EASTON AROUND 855 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...FREQUENT CLOUD TO
GROUND LIGHTNING WILL OCCUR 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.

&&

LAT...LON 3861 7609 3867 7622 3873 7625 3872 7631
      3867 7636 3874 7635 3877 7640 3879 7638
      3875 7635 3883 7631 3886 7634 3884 7638
      3888 7637 3888 7632 3883 7630 3887 7624
      3882 7621 3886 7621 3883 7598 3857 7607
TIME...MOT...LOC 0008Z 285DEG 16KT 3878 7635

$$
2 follow-up statements
000 
WWUS51 KPHI 120027
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
827 PM EDT TUE AUG 11 2009

MDC035-041-120115-
/O.CON.KPHI.SV.W.0197.000000T0000Z-090812T0115Z/
QUEEN ANNES MD-TALBOT MD-
827 PM EDT TUE AUG 11 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM EDT
FOR SOUTHERN TALBOT AND EXTREME SOUTH CENTRAL QUEEN ANNES
COUNTIES...

AT 825 PM EDT...NATIONAL WEATHER SERVICE RADAR CONTINUED TO INDICATE 
A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND 
DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED NEAR ST. 
MICHAELS...OR 10 MILES WEST OF EASTON...MOVING EAST AT 20 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  OXFORD BY 845 PM EDT...
  EASTON BY 855 PM EDT...
  HAMBLETON BY 900 PM EDT...
  TRAPPE BY 905 PM EDT...

LAT...LON 3868 7636 3875 7634 3881 7631 3882 7624
      3881 7615 3879 7600 3857 7607 3861 7609
      3867 7622 3873 7625 3872 7631 3867 7636
TIME...MOT...LOC 0027Z 285DEG 16KT 3876 7624

$$
000 
WWUS51 KPHI 120052
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
852 PM EDT TUE AUG 11 2009

MDC035-120101-
/O.CAN.KPHI.SV.W.0197.000000T0000Z-090812T0115Z/
QUEEN ANNES MD-
852 PM EDT TUE AUG 11 2009

...THE SEVERE THUNDERSTORM WARNING FOR EXTREME SOUTH CENTRAL QUEEN
ANNES COUNTY IS CANCELLED...

LAT...LON 3871 7621 3870 7615 3867 7604 3857 7607
      3861 7609 3867 7622
TIME...MOT...LOC 0051Z 285DEG 16KT 3873 7611

$$

MDC041-120115-
/O.CON.KPHI.SV.W.0197.000000T0000Z-090812T0115Z/
TALBOT MD-
852 PM EDT TUE AUG 11 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM EDT
FOR SOUTH CENTRAL TALBOT COUNTY...

AT 850 PM EDT...A SEVERE THUNDERSTORM WAS REPORTED CAPABLE OF
PRODUCING PENNY SIZE HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH. 
THIS STORM WAS LOCATED 6 MILES SOUTHEAST OF OXFORD...MOVING 
SOUTHEAST AT 15 TO 20 MPH.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  TRAPPE BY 905 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 LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 3871 7621 3870 7615 3867 7604 3857 7607
      3861 7609 3867 7622
TIME...MOT...LOC 0051Z 285DEG 16KT 3873 7611

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 9:04 PM EDTSevere Thunderstorm WarningPHITalbot26 min
Aug 12, 4:16 PM EDTAreal Flood AdvisoryPHICaroline, Queen Anne's, Talbot3 hr
Aug 12, 5:55 PM EDTFlash Flood WarningPHICecil100 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2009Every severe thunderstorm warning in 2009

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.