Alert archive / Maryland / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 15, NWS Philadelphia/Mount Holly

April 21, 2009Caroline County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 21, 2009, 7:31 PM EDT for Caroline County, Talbot County, Maryland. It was in force for 44 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
Apr 21, 2009, 7:31 PM EDT (23:31 UTC)
Expired
Apr 21, 2009, 8:15 PM EDT
In force
44 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Caroline County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 61 km from the middle of the area, began a volume at 23:32 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
Apr 21, 7:46 PM EDTTSTM WND GST 50Easton, MD

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

The nearest sounding before it

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.5 hours before the alert went out and 79 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, Phillips Aaf/Abe, MD at 12:00Z on 2009-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Phillips Aaf/Abe, MD at 12:00Z on 2009-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939587897117Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
788 m above ground
0-6 km bulk shear
62 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
182 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 212331
SVRPHI
MDC011-041-220015-
/O.NEW.KPHI.SV.W.0015.090421T2331Z-090422T0015Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
731 PM EDT TUE APR 21 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 815 PM EDT

* AT 729 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 6 MILES
  SOUTH OF TILGHMAN ISLAND...OR 15 MILES SOUTHWEST OF EASTON...AND
  MOVING NORTHEAST AT 45 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  OXFORD AND ST. MICHAELS BY 740 PM EDT...
  COPPERVILLE BY 745 PM EDT...
  EASTON BY 750 PM EDT...
  SKIPTON BY 755 PM EDT...
  CORDOVA AND MATTHEWS BY 800 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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 NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 3861 7611 3868 7619 3866 7621 3873 7625
      3867 7635 3875 7635 3877 7640 3875 7635
      3887 7626 3887 7625 3884 7626 3882 7621
      3889 7609 3895 7609 3892 7595 3881 7590
      3876 7599 3865 7596 3858 7600
TIME...MOT...LOC 2331Z 232DEG 38KT 3868 7629

$$

AMC
1 follow-up statement
000 
WWUS51 KPHI 220008
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
808 PM EDT TUE APR 21 2009

MDC011-041-220016-
/O.EXP.KPHI.SV.W.0015.000000T0000Z-090422T0015Z/
CAROLINE MD-TALBOT MD-
808 PM EDT TUE APR 21 2009

...THE SEVERE THUNDERSTORM WARNING FOR TALBOT AND SOUTHWESTERN
CAROLINE COUNTIES WILL EXPIRE AT 815 PM EDT...

THE LINE OF THUNDERSTORMS WHICH PROMPTED THE WARNING IS NOW OVER THE 
EASTERN PART OF TALBOT COUNTY AND WILL CONTINUE MOVING AWAY FROM THE 
AREA.

LAT...LON 3861 7611 3868 7619 3866 7621 3873 7625
      3867 7635 3875 7635 3877 7640 3875 7635
      3887 7626 3887 7625 3884 7626 3882 7621
      3889 7609 3895 7609 3892 7595 3881 7590
      3876 7599 3865 7596 3858 7600
TIME...MOT...LOC 0006Z 232DEG 38KT 3891 7591

$$

AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 7:51 PM EDTSevere Thunderstorm WarningPHICaroline39 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.