Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 22, NWS Philadelphia/Mount Holly

May 9, 2009Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 9, 2009, 6:54 PM EDT for Sussex County, Delaware. It was in force for 51 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
May 9, 2009, 6:54 PM EDT (22:54 UTC)
Expired
May 9, 2009, 7:45 PM EDT
In force
51 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 23 km from the middle of the area, began a volume at 22:54 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 9, 6:25 PM EDTSevere Thunderstorm WatchSPC4 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.9 hours before the alert went out and 78 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 2009-05-09Temperature 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°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 2009-05-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 225 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
-99 J/kg
Mixed-layer LCL
650 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
225 m²/s²
0-3 km storm-relative helicity
239 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.4

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 092254
SVRPHI
DEC005-092345-
/O.NEW.KPHI.SV.W.0022.090509T2254Z-090509T2345Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
654 PM EDT SAT MAY 9 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SUSSEX COUNTY IN SOUTHERN DELAWARE...
  THIS INCLUDES THE CITY OF GEORGETOWN...

* UNTIL 745 PM EDT

* AT 650 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL. THIS   
  STORM WAS LOCATED ABOUT 10 MILES WEST OF LAUREL...OR ABOUT 20
  MILES NORTHWEST OF SALISBURY...AND MOVING EAST AT ABOUT 50 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  THE LAUREL AREA BY ABOUT 705 PM EDT...  
  THE SYCAMORE AREA BY ABOUT 710 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL...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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 AM EDT SUNDAY
MORNING FOR SOUTHERN DELAWARE AND EASTERN MARYLAND.

&&

LAT...LON 3845 7564 3847 7571 3863 7572 3865 7570
      3881 7518 3879 7513 3879 7511 3881 7509
      3880 7507 3846 7503 3845 7543
TIME...MOT...LOC 2252Z 258DEG 44KT 3854 7578

$$

MPD
1 follow-up statement
000 
WWUS51 KPHI 092325
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
725 PM EDT SAT MAY 9 2009

DEC005-092345-
/O.CON.KPHI.SV.W.0022.000000T0000Z-090509T2345Z/
SUSSEX DE-
725 PM EDT SAT MAY 9 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM EDT
FOR SOUTHEASTERN SUSSEX COUNTY...

AT 724 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE HAIL...AND 
DAMAGING WINDS IN EXCESS OF 60 MPH. THIS STORM WAS LOCATED NEAR 
MILLSBORO...OR 7 MILES SOUTHEAST OF GEORGETOWN...MOVING EAST AT 50 
MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LONG
NECK...MILLVILLE...OCEAN VIEW...LEWES...FENWICK ISLAND...BETHANY
BEACH...SOUTH BETHANY...HENLOPEN ACRES...DEWEY BEACH AND REHOBOTH
BEACH

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.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 100 AM EDT SUNDAY
MORNING FOR SOUTHERN DELAWARE AND EASTERN MARYLAND.

&&

LAT...LON 3846 7566 3846 7569 3853 7563 3861 7555
      3868 7550 3881 7518 3879 7513 3879 7511
      3881 7509 3880 7507 3846 7503 3845 7543
TIME...MOT...LOC 2325Z 258DEG 44KT 3862 7527

$$

MPD

The office that day

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

IssuedProductOfficeCountiesLasted
May 9, 7:28 PM EDTSevere Thunderstorm WarningPHIKent32 min

Nearby

Severe Thunderstorm Warnings in Delaware, 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.