Alert archive / Delaware / Severe Thunderstorm Warnings in 2016

Severe Thunderstorm Warning 121, NWS Philadelphia/Mount Holly

July 20, 2016Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 20, 2016, 3:22 AM EDT for Sussex County, Delaware. It was in force for 33 min. 2 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 20, 2016, 3:22 AM EDT (07:22 UTC)
Expired: Jul 20, 2016, 3:55 AM EDT
In force: 33 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 41 km from the middle of the area, began a volume at 07:22 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
Jul 20, 3:26 AM EDT	TSTM WND GST 65	Dewey Beach, DE
Jul 20, 3:26 AM EDT	MARINE TSTM WIND 65	Dewey Beach, DE

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, 7.4 hours before the alert went out and 75 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: 1746 J/kg
Mixed-layer CIN: -20 J/kg
Mixed-layer LCL: 1050 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 66 m²/s²
Significant tornado parameter: 0.2
Supercell composite: 1.5

Open this sounding in Storm Lab

The text

As transmitted.

580 
WUUS51 KPHI 200722
SVRPHI
DEC005-200815-
/O.NEW.KPHI.SV.W.0121.160720T0722Z-160720T0815Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
322 AM EDT WED JUL 20 2016

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

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

* UNTIL 415 AM EDT

* AT 322 AM EDT...A SEVERE THUNDERSTORM WAS LOCATED NEAR HENLOPEN
  ACRES...OR 17 MILES EAST OF GEORGETOWN...MOVING SOUTH AT 15 MPH.

  HAZARD...60 MPH WIND GUSTS AND QUARTER SIZE HAIL. 

  SOURCE...RADAR INDICATED. 

  IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT WIND DAMAGE 
           TO ROOFS...SIDING...AND TREES. 

* LOCATIONS IMPACTED INCLUDE...
  MILLVILLE...HENLOPEN ACRES...LONG NECK...OCEAN VIEW...
  SOUTH BETHANY AND DEWEY BEACH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

&&

LAT...LON 3870 7520 3873 7505 3846 7504 3846 7505
      3845 7505 3845 7516
TIME...MOT...LOC 0722Z 341DEG 13KT 3866 7506 

HAIL...1.00IN
WIND...60MPH
 
$$

ROBERTSON

2 follow-up statements

087 
WWUS51 KPHI 200741
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
341 AM EDT WED JUL 20 2016

DEC005-200815-
/O.CON.KPHI.SV.W.0121.000000T0000Z-160720T0815Z/
SUSSEX DE-
341 AM EDT WED JUL 20 2016

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 415 AM EDT
FOR SOUTHEASTERN SUSSEX COUNTY...

AT 341 AM EDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
EXTENDING FROM NEAR HENLOPEN ACRES TO NEAR MILLVILLE...MOVING EAST AT
10 MPH.

HAZARD...60 MPH WIND GUSTS AND QUARTER SIZE HAIL. 

SOURCE...RADAR INDICATED. 

IMPACT...HAIL DAMAGE TO VEHICLES IS EXPECTED. EXPECT WIND DAMAGE TO 
         ROOFS...SIDING...AND TREES. 

LOCATIONS IMPACTED INCLUDE...
MILLVILLE...HENLOPEN ACRES...OCEAN VIEW...
SOUTH BETHANY AND DEWEY BEACH.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR OF A
BUILDING.

&&

LAT...LON 3872 7512 3873 7505 3865 7504 3846 7504
      3845 7505 3845 7510
TIME...MOT...LOC 0741Z 279DEG 7KT 3876 7510 3848 7506 

HAIL...1.00IN
WIND...60MPH
 
$$

ROBERTSON

188 
WWUS51 KPHI 200755
SVSPHI

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
355 AM EDT WED JUL 20 2016

DEC005-200805-
/O.CAN.KPHI.SV.W.0121.000000T0000Z-160720T0815Z/
SUSSEX DE-
355 AM EDT WED JUL 20 2016

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN SUSSEX COUNTY IS
CANCELLED...
    
THE STORMS WHICH PROMPTED THE WARNING HAVE MOVED OUT OF THE AREA.
THEREFORE THE WARNING HAS BEEN CANCELLED.

LAT...LON 3872 7512 3873 7505 3865 7504 3846 7504
      3845 7505 3845 7510
TIME...MOT...LOC 0752Z 341DEG 13KT 3872 7508 3844 7504 

$$

ROBERTSON

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 12:31 AM EDT	Special Weather Statement	PHI	Kent	44 min
Jul 20, 1:11 AM EDT	Special Weather Statement	PHI	Kent	49 min
Jul 20, 1:17 AM EDT	Special Weather Statement	PHI	Kent	43 min
Jul 20, 1:50 AM EDT	Special Weather Statement	PHI	Sussex	40 min
Jul 20, 1:53 AM EDT	Special Weather Statement	PHI	Sussex	22 min
Jul 20, 1:55 AM EDT	Special Weather Statement	PHI	Sussex	35 min
Jul 20, 2:04 AM EDT	Severe Thunderstorm Warning	PHI	Sussex	56 min
Jul 20, 2:56 AM EDT	Special Weather Statement	PHI	Sussex	64 min
Jul 20, 4:11 AM EDT	Special Weather Statement	PHI	Sussex	49 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2016 Every severe thunderstorm warning in 2016

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.