Alert archive / Maryland / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 16, NWS Philadelphia/Mount Holly

April 21, 2009Caroline County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 21, 2009, 7:51 PM EDT for Caroline County, Maryland. It was in force for 39 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
Apr 21, 2009, 7:51 PM EDT (23:51 UTC)
Expired
Apr 21, 2009, 8:30 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Caroline County, MD

The radar

The Dover AFB radar (KDOX), 40 km from the middle of the area, began a volume at 23:53 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

Phillips Aaf/Abe, MD (KAPG), launched 12:00Z, 11.9 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 212351
SVRPHI
MDC011-220030-
/O.NEW.KPHI.SV.W.0016.090421T2351Z-090422T0030Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN CAROLINE COUNTY IN EASTERN MARYLAND...

* UNTIL 830 PM EDT

* AT 750 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 NEAR
  TANYARD...OR NEAR EASTON...AND MOVING EAST AT 40 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  PRESTON BY 800 PM EDT...
  HARMONY AND 7 MILES SOUTH OF GRIFFIN BY 805 PM EDT...
  AGNER...7 MILES NORTHWEST OF FEDERALSBURG AND 7 MILES SOUTH OF
  DENTON BY 810 PM EDT...
  SMITHVILLE BY 815 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 3873 7601 3879 7597 3878 7596 3881 7590
      3883 7593 3884 7592 3889 7595 3897 7574
      3870 7572 3868 7581 3869 7583 3867 7596
TIME...MOT...LOC 2351Z 248DEG 36KT 3871 7602

$$

AMC
1 follow-up statement
000 
WWUS51 KPHI 220031
SVSPHI

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

MDC011-220040-
/O.EXP.KPHI.SV.W.0016.000000T0000Z-090422T0030Z/
CAROLINE MD-
831 PM EDT TUE APR 21 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN CAROLINE COUNTY HAS
EXPIRED...

THE STORMS WHICH PROMPTED THE WARNING HAVE MOVED EAST INTO DELAWARE.

LAT...LON 3873 7601 3879 7597 3878 7596 3881 7590
      3883 7593 3884 7592 3889 7595 3897 7574
      3870 7572 3868 7581 3869 7583 3867 7596
TIME...MOT...LOC 0030Z 248DEG 36KT 3885 7556

$$

AMC

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 7:31 PM EDTSevere Thunderstorm WarningPHICaroline, Talbot44 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.