Alert archive / Maryland / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 238, NWS Philadelphia/Mount Holly

August 9, 2021Caroline County, Maryland; Kent County, Delaware

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 9, 2021, 4:35 PM EDT for Caroline County, Maryland; Kent County, Delaware. It was in force for 40 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
Aug 9, 2021, 4:35 PM EDT (20:35 UTC)
Expired
Aug 9, 2021, 5:15 PM EDT
In force
40 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Kent County, DE, Caroline County, MD

The radar

The Dover AFB radar (KDOX), 36 km from the middle of the area, began a volume at 20:36 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 12:00Z, 8.6 hours before the alert went out and 127 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 2021-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 927 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 2021-08-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 25 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
927 J/kg
Mixed-layer CIN
-47 J/kg
Mixed-layer LCL
869 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
25 m²/s²
0-3 km storm-relative helicity
18 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

960 
WUUS51 KPHI 092035
SVRPHI
DEC001-MDC011-092115-
/O.NEW.KPHI.SV.W.0238.210809T2035Z-210809T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
435 PM EDT Mon Aug 9 2021

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  West central Kent County in central Delaware...
  Northeastern Caroline County in eastern Maryland...

* Until 515 PM EDT.

* At 435 PM EDT, a severe thunderstorm was located over Goldsboro, or
  15 miles southwest of Dover, moving east at 5 mph.

  HAZARD...60 mph wind gusts and penny size hail.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Goldsboro, Sandtown, Henderson and Marydel. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3899 7582 3905 7584 3915 7570 3898 7565
TIME...MOT...LOC 2035Z 248DEG 5KT 3905 7576 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

SFJ
1 follow-up statement
012 
WWUS51 KPHI 092049
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
449 PM EDT Mon Aug 9 2021

DEC001-MDC011-092115-
/O.CON.KPHI.SV.W.0238.000000T0000Z-210809T2115Z/
Kent DE-Caroline MD-
449 PM EDT Mon Aug 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 515 PM EDT
FOR WEST CENTRAL KENT AND NORTHEASTERN CAROLINE COUNTIES...

At 449 PM EDT, a severe thunderstorm was located over Sandtown, or 13
miles southwest of Dover, moving east at 5 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Minor damage to vehicles is possible. Wind damage to roofs, 
         siding, trees, and power lines is possible.

Locations impacted include...
Goldsboro, Sandtown, Henderson and Marydel. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3899 7582 3905 7584 3915 7570 3898 7565
TIME...MOT...LOC 2049Z 248DEG 5KT 3906 7574 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

SFJ

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 2:41 PM EDTAreal Flood AdvisoryPHICaroline, Kent, Queen Anne's3 hr
Aug 9, 4:59 PM EDTFlash Flood WarningPHICaroline, Queen Anne's79 min
Aug 9, 5:12 PM EDTSevere Thunderstorm WarningPHICaroline, Queen Anne's20 min
Aug 9, 2:10 PM EDTSpecial Weather StatementPHISussex50 min
Aug 9, 3:01 PM EDTFlash Flood WarningPHIKent, Sussex2 hr
Aug 9, 3:43 PM EDTExcessive Heat WatchPHINew Castle12 hr
Aug 9, 4:36 PM EDTAreal Flood AdvisoryPHINew Castle104 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2021Severe Thunderstorm Warnings in Delaware, 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.