Alert archive / Delaware / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 144, NWS Philadelphia/Mount Holly

July 27, 2009Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 27, 2009, 3:01 PM EDT for Sussex County, Delaware. It was in force for 59 min. 3 reports 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
Jul 27, 2009, 3:01 PM EDT (19:01 UTC)
Expired
Jul 27, 2009, 4:00 PM 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), 37 km from the middle of the area, began a volume at 19:01 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

TimeReportWhereRemark
Jul 27, 3:07 PM EDTHAIL 1Fenwick Island, DESTARTING TO COVER THE GROUND.
Jul 27, 3:10 PM EDTTSTM WND DMGFenwick Island, DESIDING RIPPED FROM A BUILDING ON GRANT AVENUE.
Jul 27, 3:23 PM EDTHAIL 0.5Fenwick Island, DESECOND STORM OVER FENWICK ISLAND.

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 12:00Z, 7.0 hours before the alert went out and 82 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 2009-07-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 103 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 2009-07-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 square meters per square second.193958Sfc1 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
103 J/kg
Mixed-layer CIN
-171 J/kg
Mixed-layer LCL
1173 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
110 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.3

Open this sounding in Storm Lab

The text

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

000 
WUUS51 KPHI 271901
SVRPHI
DEC005-272000-
/O.NEW.KPHI.SV.W.0144.090727T1901Z-090727T2000Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
301 PM EDT MON JUL 27 2009

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 400 PM EDT

* AT 302 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
  FENWICK ISLAND...OR 24 MILES SOUTHEAST OF GEORGETOWN...AND MOVING
  NORTH AT 30 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  BETHANY BEACH AND MILLVILLE AROUND 315 PM EDT...
  7 MILES EAST OF REHOBOTH BEACH AROUND 340 PM EDT...

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 3846 7521 3884 7522 3880 7516 3879 7511
      3881 7509 3880 7507 3865 7505 3863 7506
      3860 7504 3859 7505 3847 7503 3846 7503
      3844 7505
TIME...MOT...LOC 1902Z 201DEG 27KT 3843 7509

$$
 
TFG
1 follow-up statement
000 
WWUS51 KPHI 271935
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
335 PM EDT MON JUL 27 2009

DEC005-272000-
/O.CON.KPHI.SV.W.0144.000000T0000Z-090727T2000Z/
SUSSEX DE-
335 PM EDT MON JUL 27 2009

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 400 PM EDT
FOR SOUTHEASTERN SUSSEX COUNTY...

AT 331 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING PENNY SIZE
HAIL...AND DAMAGING WINDS TO 60 MPH.  THIS STORM WAS
LOCATED NEAR OCEAN VIEW...OR 19 MILES SOUTHEAST OF GEORGETOWN...
MOVING NORTH AT 30 MPH. THE STRONGEST PART OF THE STORM WAS NOW
OVER THE OCEAN. A SECOND LIKELY SEVERE THUNDERSTORM WAS APPROACHING
OCEAN CITY MARYLAND.

MARBLE TO QUARTER SIZE HAIL WAS REPORTED WITH THE FIRST SEVERE 
THUNDERSTORM IN FENWICK ISLAND.

THE SEVERE THUNDERSTORM WILL BE NEAR...
  DEWEY BEACH...REHOBOTH BEACH AND HENLOPEN ACRES BY 350 PM EDT...

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.

THIS STORM HAS A HISTORY OF PRODUCING DESTRUCTIVE WINDS AND LARGE
DAMAGING HAIL. SEEK SHELTER NOW INSIDE A STURDY STRUCTURE AND STAY
AWAY FROM WINDOWS

&&

LAT...LON 3845 7515 3873 7514 3876 7513 3879 7511
      3881 7509 3880 7507 3865 7505 3863 7506
      3860 7504 3859 7505 3847 7503 3846 7503
      3844 7505
TIME...MOT...LOC 1934Z 201DEG 27KT 3858 7507

$$
 
TFG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 27, 4:25 PM EDTSevere Thunderstorm WarningPHISussex54 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.