Alert archive / Maryland / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 174, NWS Wakefield, VA

August 18, 2017Accomack County, Virginia; Somerset County, Wicomico County, Worcester County, Maryland

NWS Wakefield, VA issued this severe thunderstorm warning at Aug 18, 2017, 9:17 PM EDT for Accomack County, Virginia; Somerset County, Wicomico County, Worcester County, Maryland. It was in force for 43 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 18, 2017, 9:17 PM EDT (01:17 UTC)
Expired: Aug 18, 2017, 10:00 PM EDT
In force: 43 min
Issued by: NWS Wakefield, VA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

Counties Somerset County, MD, Wicomico County, MD, Worcester County, MD, Accomack County, VA

The radar

The Dover AFB radar (KDOX), 82 km from the middle of the area, began a volume at 01:17 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.

Issued	Product	Office	Lasted
Aug 18, 2:27 PM EDT	Severe Thunderstorm Watch	SPC	9 hr

The nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 00:00Z, 1.3 hours before the alert went out and 29 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: 394 J/kg
Mixed-layer CIN: -110 J/kg
Mixed-layer LCL: 1406 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 33 m²/s²
0-3 km storm-relative helicity: 52 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Wakefield, VA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 18, 7:25 PM EDT, 1 hour 52 minutes earlier.

Area forecast discussion, Aug 18, 7:25 PM EDT, 1 hour 52 minutes before

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Hazardous weather outlook, Aug 18, 2:37 PM EDT, 6 hours 40 minutes before

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In the hours before

Special weather statement, Aug 18, 6:39 PM EDT, 2 hours 38 minutes before

Special Weather Statement
National Weather Service Wakefield VA
639 PM EDT FRI AUG 18 2017

VAZ061-062-068-069-511-513-515-182345-
Goochland-Western Chesterfield-Western Henrico (Including the City of
Richmond)-Western Hanover-Powhatan-Amelia-Cumberland-
639 PM EDT FRI AUG 18 2017

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT NORTHWESTERN
CHESTERFIELD...EASTERN CUMBERLAND...GOOCHLAND...NORTHWESTERN
HENRICO...WEST CENTRAL HANOVER...NORTHWESTERN AMELIA AND POWHATAN
COUNTIES AND THE CITY OF RICHMOND...

At 639 PM EDT, radar indicated strong thunderstorms were located
along a line extending from near Montpelier to near Jetersville.
Movement was northeast at 30 mph.

Wind gusts in excess of 40 mph and rainfall amounts of up to 1 inch
are possible with these storms.

Locations impacted include...
Richmond, Powhatan, Goochland, Ashland, Randolph Macon College,
Tuckahoe, Moseley, Amelia Courthouse, Bon Air, University Of
Richmond, Hanover, Oilville, Manakin, Tobaccoville, Trenholm, Morven,
Macon, Sabot, Laurel and Wyndham.

Strong wind gusts are possible with these storms. These wind gusts
are capable of knocking down tree limbs...small or weakened trees...
and blowing around trash cans...potted plants...lawn furniture and
other light outdoor objects.

Motorists should use extra caution in the vicinity of these storms.
Be prepared for rapid changes in weather and road conditions. Heavy
rain could cause ponding of water on roads...and possible minor
flooding of ditches and poor drainage areas.

LAT...LON 3775 7811 3777 7790 3773 7780 3778 7777
      3782 7741 3781 7742 3780 7739 3779 7739
      3778 7740 3778 7737 3776 7737 3737 7767
      3728 7818 3730 7823 3736 7824
TIME...MOT...LOC 2239Z 240DEG 26KT 3777 7774 3731 7818

DEROSA

Special weather statement, Aug 18, 7:08 PM EDT, 2 hours 9 minutes before

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Special weather statement, Aug 18, 7:21 PM EDT, 1 hour 56 minutes before

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Special weather statement, Aug 18, 7:30 PM EDT, 1 hour 47 minutes before

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Local storm report, Aug 18, 7:45 PM EDT, 1 hour 32 minutes before

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Local storm report, Aug 18, 7:55 PM EDT, 1 hour 22 minutes before

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The office that day

Everything else NWS Wakefield, VA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 18, 8:12 PM EDT	Special Weather Statement	AKQ	Charles City, Chesterfield, Henrico, City of Colonial Heights, City of Hopewell, City of Petersburg	63 min
Aug 18, 8:39 PM EDT	Special Marine Warning	AKQ		96 min
Aug 18, 8:39 PM EDT	Special Marine Warning	AKQ		66 min
Aug 18, 8:56 PM EDT	Areal Flood Advisory	AKQ	Amelia, Charles City, Chesterfield, Dinwiddie, Henrico, New Kent	2 hr
Aug 18, 9:26 PM EDT	Special Marine Warning	AKQ		64 min
Aug 18, 10:01 PM EDT	Special Weather Statement	AKQ	Charles City, Dinwiddie, Prince George, City of Colonial Heights, City of Hopewell, City of Petersburg	59 min
Aug 18, 10:06 PM EDT	Special Marine Warning	AKQ		54 min
Aug 18, 10:06 PM EDT	Special Weather Statement	AKQ	Brunswick, Greensville	54 min
Aug 18, 10:54 PM EDT	Special Weather Statement	AKQ	Dinwiddie, Greensville, Southampton, Sussex, City of Emporia, City of Franklin	66 min
Aug 18, 11:14 PM EDT	Severe Thunderstorm Warning	AKQ	Southampton, Surry, Sussex	33 min
Aug 18, 11:59 PM EDT	Special Weather Statement	AKQ	Isle of Wight, Surry, York, City of Franklin, City of Hampton, City of Newport News and 4 more	46 min
Aug 19, 12:55 AM EDT	Special Weather Statement	AKQ	Northampton, York, City of Chesapeake, City of Hampton, City of Norfolk, City of Poquoson and 3 more	65 min
Aug 19, 1:19 AM EDT	Special Marine Warning	AKQ		56 min
Aug 18, 8:07 PM EDT	Special Weather Statement	AKQ	Dorchester	38 min
Aug 18, 8:34 PM EDT	Special Weather Statement	AKQ	Dorchester	56 min
Aug 18, 8:48 PM EDT	Areal Flood Advisory	AKQ	Dorchester	3 hr
Aug 18, 8:52 PM EDT	Special Weather Statement	AKQ	Somerset	38 min

Nearby

Severe Thunderstorm Warnings in Maryland, 2017 Severe Thunderstorm Warnings in Virginia, 2017 Every severe thunderstorm warning in 2017

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.