Alert archive / Maryland / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 12, NWS Philadelphia/Mount Holly

May 12, 2018Kent County, Sussex County, Delaware; Caroline County, Kent County, Queen Anne's County, Maryland

NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 12, 2018, 8:51 PM EDT for Kent County, Sussex County, Delaware; Caroline County, Kent County, Queen Anne's County, Maryland. It was in force for 39 min. 5 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
May 12, 2018, 8:51 PM EDT (00:51 UTC)
Expired
May 12, 2018, 9:30 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Kent County, DE, Sussex County, DE, Caroline County, MD, Kent County, MD, Queen Anne's County, MD

The radar

The Dover AFB radar (KDOX), 30 km from the middle of the area, began a volume at 00:52 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

TimeReportWhereRemark
May 12, 8:52 PM EDTTSTM WND DMGFelton Manor, DEDOWNED ELECTRICAL POLE AND WIRES FROM STRONG THUNDERSTORM WINDS.
May 12, 8:52 PM EDTHAIL 1Highland Acres, DEPHOTO OF QUARTER SIZED HAIL IN HIGHLAND ACRES. TIME APPROXIMATED FROM RADAR.
May 12, 8:56 PM EDTHAIL 1Magnolia, DETIME APPROXIMATED FROM RADAR.
May 12, 8:56 PM EDTHAIL 1.51 Nne White House Landi, DE
May 12, 8:58 PM EDTHAIL 1Frederica, DETIME APPROXIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
May 12, 4:58 PM EDTTornado WatchSPC5 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 0.9 hours before the alert went out and 122 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 00:00Z on 2018-05-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1641 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 00:00Z on 2018-05-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 159 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
1641 J/kg
Mixed-layer CIN
-127 J/kg
Mixed-layer LCL
1626 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
159 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.1

Open this sounding in Storm Lab

The text

As transmitted.

284 
WUUS51 KPHI 130051
SVRPHI
DEC001-005-MDC011-029-035-130130-
/O.NEW.KPHI.SV.W.0012.180513T0051Z-180513T0130Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
851 PM EDT SAT MAY 12 2018

The National Weather Service in Mount Holly NJ has issued a

* Severe Thunderstorm Warning for...
  Northern Sussex County in southern Delaware...
  Kent County in central Delaware...
  Queen Anne's County in northeastern Maryland...
  Northeastern Caroline County in eastern Maryland...
  Southwestern Kent County in northeastern Maryland...

* Until 930 PM EDT.

* At 851 PM EDT, severe thunderstorms were located along a line
  extending from Dover Base Housing to Centreville, moving east at 40
  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...
  Dover, Centerville, Milford, Denton, Centreville, Harrington,
  Camden, Greensboro, Oakland, Ridgely, Church Hill, Sudlersville,
  Bowers, Goldsboro, Woodside, Viola, Hartly, Old Town, Rising
  Sun-Lebanon and Starr.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

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 100 AM EDT for central and
southern Delaware...and eastern and northeastern Maryland.

LAT...LON 3906 7623 3921 7602 3916 7537 3905 7537
      3901 7533 3892 7528 3883 7516 3881 7534
      3884 7565 3903 7624 3904 7624
TIME...MOT...LOC 0051Z 284DEG 36KT 3912 7550 3904 7607 

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

JRK
1 follow-up statement
895 
WWUS51 KPHI 130115
SVSPHI

Severe Weather Statement
National Weather Service Mount Holly NJ
915 PM EDT SAT MAY 12 2018

MDC029-130124-
/O.CAN.KPHI.SV.W.0012.000000T0000Z-180513T0130Z/
Kent MD-
915 PM EDT SAT MAY 12 2018

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHWESTERN KENT COUNTY IS
CANCELLED...

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

A tornado watch remains in effect until 100 AM EDT for central and
southern Delaware...and eastern and northeastern Maryland.

LAT...LON 3900 7614 3911 7564 3913 7537 3905 7537
      3892 7528 3883 7516 3881 7536 3884 7565
TIME...MOT...LOC 0114Z 284DEG 33KT 3900 7532 3894 7579 

$$

DEC001-005-MDC011-035-130130-
/O.CON.KPHI.SV.W.0012.000000T0000Z-180513T0130Z/
Sussex DE-Kent DE-Queen Anne's MD-Caroline MD-
915 PM EDT SAT MAY 12 2018

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 930 PM EDT
FOR NORTHERN SUSSEX...SOUTHERN KENT...CENTRAL QUEEN ANNE'S AND
NORTHEASTERN CAROLINE COUNTIES...

At 914 PM EDT, severe thunderstorms were located along a line
extending from Big Stone Beach to near Greensboro, moving east at 40
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...
Dover, Milford, Denton, Harrington, Camden, Greensboro, Oakland,
Ridgely, Bowers, Goldsboro, Woodside, Viola, Rising Sun-Lebanon,
Starr, Jumptown, Dover Base Housing, Sandtown, Andrewsville, Rising
Sun and Wyoming.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In addition to large hail and damaging winds, frequent cloud to
ground lightning is occurring with this storm. Move indoors
immediately. Remember, if you can hear thunder, you are close enough
to be struck by lightning.

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 100 AM EDT for central and
southern Delaware...and eastern and northeastern Maryland.

LAT...LON 3900 7614 3911 7564 3913 7537 3905 7537
      3892 7528 3883 7516 3881 7536 3884 7565
TIME...MOT...LOC 0114Z 284DEG 33KT 3900 7532 3894 7579 

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

JRK

The office that day

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

IssuedProductOfficeCountiesLasted
May 12, 8:11 PM EDTSevere Thunderstorm WarningPHIKent, New Castle49 min
May 12, 8:50 PM EDTFlash Flood WarningPHIKent, New Castle3 hr
May 12, 9:14 PM EDTAreal Flood AdvisoryPHIKent2 hr
May 12, 9:27 PM EDTSevere Thunderstorm WarningPHIKent, Sussex63 min
May 12, 10:28 PM EDTAreal Flood AdvisoryPHISussex65 min
May 12, 8:40 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot50 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2018Severe Thunderstorm Warnings in Delaware, 2018Every severe thunderstorm warning in 2018

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.