Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 10, NWS Philadelphia/Mount Holly

April 6, 2009Kent County, Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Apr 6, 2009, 7:10 AM EDT for Kent County, Sussex County, Delaware. It was in force for 50 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 6, 2009, 7:10 AM EDT (11:10 UTC)
Expired: Apr 6, 2009, 8:00 AM EDT
In force: 50 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Kent County, DE, Sussex County, DE

The radar

The Dover AFB radar (KDOX), 28 km from the middle of the area, began a volume at 11:13 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

Time	Report	Where	Remark
Apr 6, 7:18 AM EDT	HAIL 0.25	3 Wsw Woodland Beach, DE	PEA SIZE HAIL REPORTED IN AREAS SURROUNDING DOVER AFB.

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

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 11.2 hours before the alert went out and 127 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2490 m above ground
0-6 km bulk shear: 46 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 128 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 061110
SVRPHI
DEC001-005-061200-
/O.NEW.KPHI.SV.W.0010.090406T1110Z-090406T1200Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
710 AM EDT MON APR 6 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  KENT COUNTY IN CENTRAL DELAWARE...
  THIS INCLUDES THE CITY OF DOVER...
  NORTH CENTRAL SUSSEX COUNTY IN SOUTHERN DELAWARE...

* UNTIL 800 AM EDT

* AT 709 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL AND
  POSSIBLY SOME STRONG GUSTY WINDS.  THIS STORM WAS LOCATED NEAR 
  VIOLA...OR 11 MILES SOUTH OF DOVER...AND MOVING NORTHEAST AT 50 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  RISING SUN...WOODSIDE AND CAMDEN BY 715 AM EDT...
  BOWERS...DOVER AND 6 MILES SOUTHEAST OF DOVER SPEEDWAY BY 720 AM
  EDT...

IF YOU SEE THREATENING WEATHER, PLEASE MOVE INDOORS QUICKLY.

LAT...LON 3922 7574 3937 7550 3932 7543 3924 7538
      3920 7538 3916 7540 3907 7539 3903 7533
      3898 7529 3893 7530 3889 7525 3882 7520
      3861 7555
TIME...MOT...LOC 1109Z 225DEG 47KT 3901 7558

$$

TFG

1 follow-up statement

000 
WWUS51 KPHI 061145
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
745 AM EDT MON APR 6 2009

DEC001-061155-
/O.CAN.KPHI.SV.W.0010.000000T0000Z-090406T1200Z/
KENT DE-
745 AM EDT MON APR 6 2009

...THE SEVERE THUNDERSTORM WARNING FOR KENT COUNTY IS CANCELLED...

THE THUNDERSTORM HAS MOVED ACROSS DELAWARE BAY.

LAT...LON 3886 7543 3895 7533 3894 7530 3893 7530
      3889 7525 3884 7521 3882 7520 3877 7529
TIME...MOT...LOC 1145Z 222DEG 42KT 3887 7526

$$

DEC005-061200-
/O.CON.KPHI.SV.W.0010.000000T0000Z-090406T1200Z/
SUSSEX DE-
745 AM EDT MON APR 6 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 AM EDT
FOR NORTH CENTRAL SUSSEX COUNTY...

AT 744 AM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING NICKEL SIZE HAIL.
THIS STORM WAS LOCATED NEAR SLAUGHTER BEACH...OR 14 MILES NORTHEAST
OF GEORGETOWN...MOVING NORTHEAST AT 50 MPH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. IF YOU ARE IN ITS PATH...PREPARE
IMMEDIATELY FOR DAMAGING WINDS...DESTRUCTIVE HAIL...AND DEADLY CLOUD
TO GROUND LIGHTNING. PEOPLE OUTSIDE SHOULD MOVE TO A SHELTER...
PREFERABLY INSIDE A STRONG BUILDING BUT AWAY FROM WINDOWS.

&&

LAT...LON 3886 7543 3895 7533 3894 7530 3893 7530
      3889 7525 3884 7521 3882 7520 3877 7529
TIME...MOT...LOC 1145Z 222DEG 42KT 3887 7526

$$

TFG

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 6, 10:51 AM EDT	Severe Thunderstorm Warning	PHI	Sussex	39 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2009 Every 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.