Alert archive / Delaware / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 121, NWS Philadelphia/Mount Holly

July 29, 2010Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 29, 2010, 1:39 PM EDT for Sussex County, Delaware. It was in force for 34 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
Jul 29, 2010, 1:39 PM EDT (17:39 UTC)
Expired
Jul 29, 2010, 2:13 PM EDT
In force
34 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 32 km from the middle of the area, began a volume at 17:39 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
Jul 29, 11:54 AM EDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 5.7 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 2010-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1121 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 2010-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 90 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
1121 J/kg
Mixed-layer CIN
-63 J/kg
Mixed-layer LCL
948 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
90 m²/s²
0-3 km storm-relative helicity
98 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.

127 
WUUS51 KPHI 291739
SVRPHI
DEC005-291915-
/O.NEW.KPHI.SV.W.0121.100729T1739Z-100729T1915Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
139 PM EDT THU JUL 29 2010

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ HAS ISSUED A

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

* UNTIL 315 PM EDT

* AT 135 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
  SEVERE THUNDERSTORM CAPABLE OF PRODUCING DAMAGING WINDS IN EXCESS
  OF 60 MPH.  THIS STORM WAS LOCATED NEAR SYCAMORE...OR 7 MILES
  SOUTHWEST OF GEORGETOWN...AND MOVING EAST AT 10 MPH.

* THE SEVERE THUNDERSTORM WILL BE NEAR...
  6 MILES NORTH OF GUMBORO AROUND 220 PM EDT...
  MILLSBORO AROUND 225 PM EDT...
  DAGSBORO AROUND 250 PM EDT...
  SELBYVILLE AROUND 310 PM EDT...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

THIS IS A DANGEROUS STORM. PEOPLE OUTSIDE SHOULD MOVE INTO A 
STRONG BUILDING BUT AWAY FROM WINDOWS.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 PM EDT
THURSDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND SOUTHERN
NEW JERSEY.

&&

LAT...LON 3852 7554 3868 7545 3865 7512 3860 7515
      3859 7517 3859 7516 3845 7523 3845 7539
TIME...MOT...LOC 1739Z 291DEG 8KT 3859 7544

$$

KRUZDLO
1 follow-up statement
459 
WWUS51 KPHI 291813
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
213 PM EDT THU JUL 29 2010

DEC005-291823-
/O.CAN.KPHI.SV.W.0121.000000T0000Z-100729T1915Z/
SUSSEX DE-
213 PM EDT THU JUL 29 2010

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

THE STORM THAT PROMPTED THE WARNING HAS WEAKENED AND IS NO LONGER 
SEVERE.  

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 PM 
EDT THURSDAY EVENING FOR DELAWARE AND NORTHEASTERN MARYLAND AND 
SOUTHERN NEW JERSEY.

LAT...LON 3852 7554 3868 7545 3865 7512 3860 7515
      3859 7517 3859 7516 3845 7523 3845 7539
TIME...MOT...LOC 1813Z 291DEG 8KT 3856 7535

$$

NIERENBERG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 1:20 PM EDTSpecial Weather StatementPHISussex55 min
Jul 29, 2:28 PM EDTSpecial Weather StatementPHIKent, New Castle, Sussex92 min
Jul 29, 2:53 PM EDTSevere Thunderstorm WarningPHIKent, Sussex41 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2010Every severe thunderstorm warning in 2010

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.