Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 79, NWS Philadelphia/Mount Holly

June 15, 2009Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 15, 2009, 6:17 PM EDT for Sussex County, Delaware. 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
Jun 15, 2009, 6:17 PM EDT (22:17 UTC)
Expired
Jun 15, 2009, 6:56 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 29 km from the middle of the area, began a volume at 22:17 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.3 hours before the alert went out and 80 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 2009-06-15Temperature 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, Wallops Is Stn, VA at 12:00Z on 2009-06-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -66 square meters per square second.1939587897Sfc1 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
1093 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-66 m²/s²
0-3 km storm-relative helicity
-54 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 152217
SVRPHI
DEC005-152315-
/O.NEW.KPHI.SV.W.0079.090615T2217Z-090615T2315Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
617 PM EDT MON JUN 15 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHWESTERN SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 715 PM EDT

* AT 615 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND    
  DAMAGING WINDS UP TO 60 MPH.  THIS STORM WAS LOCATED NEAR          
  SEAFORD...OR 15 MILES WEST OF GEORGETOWN...AND MOVING SOUTH AT     
  15 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  SEAFORD AROUND 635 PM EDT...
  LAUREL AROUND 705 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.

HEAVY RAIN WILL FALL FROM THIS STORM WHICH MAY CAUSE WATER TO POND 
ON ROADS AND ALSO FLOODING OF POOR DRAINAGE AREAS.

&&

LAT...LON 3873 7571 3874 7564 3846 7549 3846 7570
TIME...MOT...LOC 2216Z 344DEG 11KT 3870 7567

$$

GORSE/DEFINO
1 follow-up statement
000 
WWUS51 KPHI 152256
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
656 PM EDT MON JUN 15 2009

DEC005-152304-
/O.CAN.KPHI.SV.W.0079.000000T0000Z-090615T2315Z/
SUSSEX DE-
656 PM EDT MON JUN 15 2009

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN SUSSEX COUNTY IS
CANCELLED...

THE THUNDERSTORM THAT PROMPTED THE WARNING HAS WEAKENED, THEREFORE 
THE WARNING HAS BEEN CANCELLED.

HOWEVER, PEA SIZE HAIL AND HEAVY RAIN CAN STILL OCCUR WITH THIS 
STORM ALONG WITH SOME CLOUD TO GROUND LIGHTNING.

LAT...LON 3873 7571 3874 7564 3846 7549 3846 7570
TIME...MOT...LOC 2254Z 344DEG 11KT 3859 7563

$$

GORSE/DEFINO

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.