Alert archive / Delaware / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 292, NWS Philadelphia/Mount Holly

September 1, 2021Kent County, Sussex County, Delaware; Caroline County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Sep 1, 2021, 6:57 PM EDT for Kent County, Sussex County, Delaware; Caroline County, Maryland. It was in force for 63 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
Sep 1, 2021, 6:57 PM EDT (22:57 UTC)
Expired
Sep 1, 2021, 8:00 PM EDT
In force
63 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Kent County, DE, Sussex County, DE, Caroline County, MD

The radar

The Dover AFB radar (KDOX), 22 km from the middle of the area, began a volume at 23:01 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Sep 1, 12:40 PM EDTTornado WatchSPC9 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 11.0 hours before the alert went out and 85 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 2021-09-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 515 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 2021-09-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 57 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
515 J/kg
Mixed-layer CIN
-76 J/kg
Mixed-layer LCL
955 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
57 m²/s²
0-3 km storm-relative helicity
89 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

As transmitted.

250 
WUUS51 KPHI 012257
SVRPHI
DEC001-005-MDC011-020000-
/O.NEW.KPHI.SV.W.0292.210901T2257Z-210902T0000Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
657 PM EDT Wed Sep 1 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Sussex County in southern Delaware...
  Southeastern Kent County in central Delaware...
  Southeastern Caroline County in eastern Maryland...

* Until 800 PM EDT.

* At 656 PM EDT, severe thunderstorms were located along a line
  extending from near Hurlock to Sharptown to near Princess Anne,
  moving northeast at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Damage to roofs, siding, trees, and power lines is 
           possible.

* Locations impacted include...
  Dover, Georgetown, Milford, Seaford, Millsboro, Laurel, Harrington,
  Lewes, Federalsburg, Milton, Bridgeville, Delmar, Dagsboro,
  Ellendale, Bowers, Smithville, Gumboro, Agner, Andrewsville and
  Sycamore.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware...and eastern Maryland.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware...and eastern Maryland.

&&

LAT...LON 3846 7569 3865 7571 3869 7577 3868 7580
      3870 7580 3871 7584 3870 7587 3921 7538
      3890 7515 3847 7524 3845 7528
TIME...MOT...LOC 2256Z 223DEG 38KT 3864 7583 3851 7572 3825 7577 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann
2 follow-up statements
239 
WWUS51 KPHI 012316
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
716 PM EDT Wed Sep 1 2021

DEC001-005-MDC011-020000-
/O.CON.KPHI.SV.W.0292.000000T0000Z-210902T0000Z/
Sussex DE-Kent DE-Caroline MD-
716 PM EDT Wed Sep 1 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SUSSEX...SOUTHEASTERN KENT AND EAST CENTRAL CAROLINE COUNTIES...

At 716 PM EDT, severe thunderstorms were located along a line
extending from near Andrewsville to near Bridgeville to near Delmar,
moving northeast at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Dover, Georgetown, Milford, Seaford, Millsboro, Laurel, Harrington,
Lewes, Milton, Bridgeville, Delmar, Dagsboro, Ellendale, Bowers,
Smithville, Gumboro, Andrewsville, Sycamore, Big Stone Beach and
Rising Sun-Lebanon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware...and eastern Maryland.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

For your protection move to an interior room on the lowest floor of a
building.

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 3863 7570 3871 7568 3876 7572
      3879 7578 3921 7538 3890 7515 3847 7524
      3845 7528
TIME...MOT...LOC 2316Z 229DEG 38KT 3883 7567 3870 7556 3844 7561 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann
980 
WWUS51 KPHI 012337
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
737 PM EDT Wed Sep 1 2021

MDC011-012347-
/O.CAN.KPHI.SV.W.0292.000000T0000Z-210902T0000Z/
Caroline MD-
737 PM EDT Wed Sep 1 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL CAROLINE COUNTY
IS CANCELLED...

The storms which prompted the warning have weakened. moved out of 
the warned area. Therefore, the warning has been cancelled.

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware.

LAT...LON 3846 7555 3865 7557 3878 7554 3893 7553
      3899 7559 3921 7538 3890 7515 3847 7524
      3845 7528
TIME...MOT...LOC 2337Z 222DEG 38KT 3906 7544 3886 7537 3864 7535 

$$

DEC001-005-020000-
/O.CON.KPHI.SV.W.0292.000000T0000Z-210902T0000Z/
Sussex DE-Kent DE-
737 PM EDT Wed Sep 1 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM EDT
FOR SUSSEX AND SOUTHEASTERN KENT COUNTIES...

At 737 PM EDT, severe thunderstorms were located along a line
extending from Bowers to near Ellendale to near Georgetown, moving
northeast at 45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Damage to roofs, siding, trees, and power lines is 
         possible.

Locations impacted include...
Dover, Georgetown, Milford, Millsboro, Lewes, Milton, Dagsboro,
Ellendale, Bowers, Gumboro, Sycamore, Big Stone Beach, Rising
Sun-Lebanon, Felton, Frankford, Frederica, Houston, Magnolia and
Riverview.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 1000 PM EDT for central and
southern Delaware.

Remain alert for a possible tornado! Tornadoes can develop quickly
from severe thunderstorms. If you spot a tornado go at once into the
basement or small central room in a sturdy structure.

For your protection move to an interior room on the lowest floor of a
building.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3846 7555 3865 7557 3878 7554 3893 7553
      3899 7559 3921 7538 3890 7515 3847 7524
      3845 7528
TIME...MOT...LOC 2337Z 222DEG 38KT 3906 7544 3886 7537 3864 7535 

TORNADO...POSSIBLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

Staarmann

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 1, 6:19 AM EDTAreal Flood AdvisoryPHINew Castle116 min
Sep 1, 6:49 AM EDTFlash Flood WarningPHINew Castle86 min
Sep 1, 8:03 AM EDTRiver Flood WarningPHINew Castle4 hr
Sep 1, 2:53 PM EDTFlash Flood WarningPHINew Castle9 hr
Sep 1, 4:59 PM EDTTornado WarningPHIKent, Sussex46 min
Sep 1, 5:01 PM EDTTornado WarningPHIKent, New Castle44 min
Sep 1, 5:16 PM EDTSevere Thunderstorm WarningPHIKent, Sussex44 min
Sep 1, 5:26 PM EDTFlash Flood WarningPHINew Castle9 hr
Sep 1, 5:35 PM EDTTornado WarningPHIKent, New Castle25 min
Sep 1, 6:03 PM EDTSevere Thunderstorm WarningPHIKent, Sussex42 min
Sep 1, 6:08 PM EDTRiver Flood WarningPHINew Castle18 hr
Sep 1, 6:15 PM EDTRiver Flood WarningPHINew Castle9 hr
Sep 1, 6:24 PM EDTTornado WarningPHINew Castle16 min
Sep 1, 6:38 PM EDTRiver Flood WarningPHINew Castle28 hr
Sep 1, 7:44 PM EDTRiver Flood WarningPHINew Castle11 hr
Sep 1, 3:16 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot44 min
Sep 1, 5:36 PM EDTTornado WarningPHIKent24 min

Nearby

Severe Thunderstorm Warnings in Delaware, 2021Severe Thunderstorm Warnings in Maryland, 2021Every severe thunderstorm warning in 2021

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.