Alert archive / Delaware / Severe Thunderstorm Warnings in 2016

Severe Thunderstorm Warning 120, NWS Philadelphia/Mount Holly

July 20, 2016Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Jul 20, 2016, 2:04 AM EDT for Sussex County, Delaware. It was in force for 56 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 20, 2016, 2:04 AM EDT (06:04 UTC)
Expired: Jul 20, 2016, 3:00 AM EDT
In force: 56 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), 30 km from the middle of the area, began a volume at 06:06 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 00:00Z, 6.1 hours before the alert went out and 74 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.

344 
WUUS51 KPHI 200604
SVRPHI
DEC005-200700-
/O.NEW.KPHI.SV.W.0120.160720T0604Z-160720T0700Z/

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

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

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

* UNTIL 300 AM EDT

* AT 203 AM EDT...SEVERE THUNDERSTORMS WERE LOCATED ALONG A LINE
  EXTENDING FROM SMITHVILLE TO HEBRON...MOVING EAST 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...
  GEORGETOWN...SEAFORD...LAUREL...BRIDGEVILLE...DELMAR...ELLENDALE...
  GUMBORO...SYCAMORE...BLADES AND BETHEL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM...AND
THE STORM WILL AFFECT THE BEACHES. FOR YOUR SAFETY...IMMEDIATELY MOVE
OFF THE BEACH AND SEEK SHELTER INDOORS.

TORRENTIAL RAINFALL IS OCCURRING WITH THESE STORMS...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 3846 7569 3849 7570 3878 7572 3884 7533
      3845 7533
TIME...MOT...LOC 0603Z 269DEG 15KT 3877 7570 3843 7570 

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

ROBERTSON

1 follow-up statement

788 
WWUS51 KPHI 200631
SVSPHI

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

DEC005-200700-
/O.CON.KPHI.SV.W.0120.000000T0000Z-160720T0700Z/
SUSSEX DE-
231 AM EDT WED JUL 20 2016

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 300 AM EDT
FOR SOUTHWESTERN SUSSEX COUNTY...

AT 231 AM EDT...A SEVERE THUNDERSTORM WAS LOCATED OVER SYCAMORE...OR
7 MILES SOUTHWEST OF GEORGETOWN...MOVING EAST AT 25 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...
GEORGETOWN...SEAFORD...LAUREL...DELMAR...GUMBORO...SYCAMORE...
BLADES AND BETHEL.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

TORRENTIAL RAINFALL IS OCCURRING WITH THIS STORM...AND MAY LEAD TO
FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED ROADWAYS.

&&

LAT...LON 3846 7563 3867 7563 3870 7533 3845 7533
TIME...MOT...LOC 0631Z 271DEG 20KT 3859 7546 

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

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, 2:56 AM EDT	Special Weather Statement	PHI	Sussex	64 min
Jul 20, 3:22 AM EDT	Severe Thunderstorm Warning	PHI	Sussex	33 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.