Alert archive / Virginia / Tornado Watches in 2017

Tornado Watch 132

April 6, 20174 counties in Maryland; 37 counties in North Carolina; 57 counties in Virginia

The Storm Prediction Center issued this tornado watch at Apr 6, 2017, 7:06 AM EDT for 4 counties in Maryland; 37 counties in North Carolina; 57 counties in Virginia. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Apr 6, 2017, 7:06 AM EDT (11:06 UTC)
Expired
Apr 6, 2017, 3:25 PM EDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 98 counties

Dorchester County, MD, Somerset County, MD, Wicomico County, MD, Worcester County, MD, Alamance County, NC, Bertie County, NC, Camden County, NC, Chatham County, NC, Chowan County, NC, Cumberland County, NC, Currituck County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Pasquotank County, NC, Perquimans County, NC, Person County, NC, Pitt County, NC, Sampson County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Accomack County, VA, Amelia County, VA, Appomattox County, VA, Brunswick County, VA, Buckingham County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 74 km from the middle of the area, began a volume at 11:06 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
30%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

10 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 6, 7:31 AM EDTSevere Thunderstorm WarningRAHChatham, Durham, Granville, Orange, Wake44 min
Apr 6, 7:54 AM EDTSevere Thunderstorm WarningRAHCumberland, Sampson38 min
Apr 6, 7:55 AM EDTSevere Thunderstorm WarningRAHVance, Warren35 min
Apr 6, 8:26 AM EDTSevere Thunderstorm WarningRAHJohnston, Sampson, Wayne, Wilson49 min
Apr 6, 9:20 AM EDTSevere Thunderstorm WarningAKQChesterfield, Henrico, City of Richmond25 min
Apr 6, 11:52 AM EDTSevere Thunderstorm WarningAKQGloucester, James City, King and Queen, Mathews, Middlesex38 min
Apr 6, 12:04 PM EDTSevere Thunderstorm WarningAKQLancaster, Northumberland, Richmond41 min
Apr 6, 12:14 PM EDTSevere Thunderstorm WarningAKQLouisa16 min
Apr 6, 12:24 PM EDTSevere Thunderstorm WarningAKQGloucester, Mathews, Middlesex, York51 min
Apr 6, 12:36 PM EDTTornado WarningAKQCity of Chesapeake, City of Norfolk, City of Portsmouth, City of Virginia Beach24 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Roanoke, VA (KRNK), launched 00:00Z, 11.1 hours before the alert went out and 154 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, Roanoke, VA at 00:00Z on 2017-04-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Roanoke, VA at 00:00Z on 2017-04-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 311 square meters per square second.1939587897117136Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1255 m above ground
0-6 km bulk shear
72 kt
0-1 km storm-relative helicity
311 m²/s²
0-3 km storm-relative helicity
305 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

420 
WWUS20 KWNS 061102
SEL2  
SPC WW 061102
NCZ000-VAZ000-CWZ000-061700-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 132
NWS Storm Prediction Center Norman OK
705 AM EDT Thu Apr 6 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Parts of central and eastern North Carolina
  Southeastern Virginia
  Coastal Waters

* Effective this Thursday morning and afternoon from 705 AM until
  100 PM EDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging wind gusts to 70 mph possible
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...Some increase in thunderstorm coverage/intensity is
expected this morning as a strong storm system pivots northeastward
over North Carolina and Virginia.  Damaging winds should be the main
risk with a broken band of storms, though some supercell structures
will be possible with an attendant risk for isolated large hail and
a couple of tornadoes.

The tornado watch area is approximately along and 70 statute miles
east and west of a line from 45 miles north northeast of Richmond VA
to 25 miles east of Fayetteville NC. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU2).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 60 knots. A few cumulonimbi with maximum tops to 400. Mean
storm motion vector 21050.

...Thompson

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 6, 5:59 AM EDTMesoscale DiscussionSPCCalvert, Charles, Dorchester, Saint Mary's91 min
Apr 6, 12:18 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Caroline, Cecil, Charles, Dorchester and 9 more57 min
Apr 6, 12:45 PM EDTSevere Thunderstorm WatchSPCAnne Arundel, Baltimore, Calvert, Caroline, Cecil, Charles and 9 more4 hr
Apr 6, 3:12 PM EDTMesoscale DiscussionSPCCecil, Kent63 min
Apr 5, 11:50 PM EDTSevere Thunderstorm WatchSPCAlexander, Cabarrus, Catawba, Cleveland, Davie, Gaston and 5 more6 hr
Apr 6, 12:51 AM EDTMesoscale DiscussionSPCAlamance, Anson, Caswell, Chatham, Davidson, Durham and 15 more114 min
Apr 6, 2:54 AM EDTMesoscale DiscussionSPCAlamance, Anson, Cabarrus, Davidson, Guilford, Montgomery and 4 more96 min
Apr 6, 10:38 AM EDTMesoscale DiscussionSPCBertie, Chowan, Edgecombe, Gates, Greene, Halifax and 8 more67 min

Nearby

Tornado Watches in Virginia, 2017Tornado Watches in North Carolina, 2017Tornado Watches in Maryland, 2017Every tornado watch 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.