Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 56, NWS Philadelphia/Mount Holly

June 9, 2009Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jun 9, 2009, 8:31 AM EDT for Sussex County, Delaware. It was in force for 59 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 9, 2009, 8:31 AM EDT (12:31 UTC)
Expired
Jun 9, 2009, 9:30 AM EDT
In force
59 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 28 km from the middle of the area, began a volume at 12:33 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, 0.5 hours before the alert went out and 71 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 2009-06-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1362 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 2009-06-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 27 square meters per square second.1939Sfc1 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
1362 J/kg
Mixed-layer CIN
-37 J/kg
Mixed-layer LCL
1059 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
27 m²/s²
0-3 km storm-relative helicity
14 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 091231
SVRPHI
DEC005-091330-
/O.NEW.KPHI.SV.W.0056.090609T1231Z-090609T1330Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
831 AM EDT TUE JUN 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 930 AM EDT

* AT 827 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL...AND
  DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS LOCATED 11
  MILES SOUTH OF LAUREL...OR NEAR SALISBURY...AND MOVING NORTHEAST AT
  25 MPH. OTHER SEVERE THUNDERSTORMS MAY FORM IN SUSSEX COUNTY
  DURING THIS TIME.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  LAUREL AROUND 900 AM EDT...
  8 MILES NORTHWEST OF GUMBORO AROUND 910 AM EDT...
  SYCAMORE AROUND 920 AM EDT...
  GEORGETOWN AND 7 MILES WEST OF MILLSBORO AROUND 930 AM 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 RAINS WILL ALSO BE OCCURRING...DONT 
DRIVE INTO FLOODED ROADS.

&&

LAT...LON 3845 7564 3847 7571 3864 7572 3883 7562
      3862 7511 3860 7512 3861 7514 3858 7514
      3845 7533
TIME...MOT...LOC 1229Z 219DEG 15KT 3841 7562

$$

JRP

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 9, 8:20 AM EDTAreal Flood AdvisoryPHINew Castle3 hr
Jun 9, 9:09 AM EDTAreal Flood AdvisoryPHIKent, Sussex3 hr
Jun 9, 1:49 PM EDTFlash Flood WatchPHINew Castle5 hr
Jun 9, 4:19 PM EDTSevere Thunderstorm WarningPHIKent, New Castle56 min
Jun 9, 5:13 PM EDTSevere Thunderstorm WarningPHIKent, New Castle92 min
Jun 9, 6:57 PM EDTSevere Thunderstorm WarningPHIKent39 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.