Alert archive / Virginia / Tornado Watches in 2008

Tornado Watch 68

February 18, 20089 counties in North Carolina; 14 counties in Virginia

The Storm Prediction Center issued this tornado watch at Feb 18, 2008, 3:59 AM EST for 9 counties in North Carolina; 14 counties in Virginia. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Feb 18, 2008, 3:59 AM EST (08:59 UTC)
Expired
Feb 18, 2008, 10:25 AM EST
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
60 kt
All 23 counties

Bertie County, NC, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, City of Chesapeake, VA, City of Franklin, VA, City of Hampton, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Isle of Wight County, VA, Northampton County, VA, Southampton County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 73 km from the middle of the area, began a volume at 09:02 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
20%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
50%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Feb 18, 4:06 AM ESTSevere Thunderstorm WarningAKQBertie54 min
Feb 18, 4:58 AM ESTSevere Thunderstorm WarningAKQChowan, Gates, Hertford, Perquimans54 min
Feb 18, 5:11 AM ESTSevere Thunderstorm WarningAKQBertie34 min
Feb 18, 5:30 AM ESTTornado WarningAKQPerquimans20 min
Feb 18, 5:41 AM ESTSevere Thunderstorm WarningAKQPasquotank26 min
Feb 18, 5:55 AM ESTSevere Thunderstorm WarningAKQCamden, Currituck35 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

Wallops Is Stn, VA (KWAL), launched 00:00Z, 9.0 hours before the alert went out and 185 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 2008-02-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCLLFCEL10008507005003002001001 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, Wallops Is Stn, VA at 00:00Z on 2008-02-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 359 square meters per square second.19395878Sfc1 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
458 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
359 m²/s²
0-3 km storm-relative helicity
421 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000
WWUS20 KWNS 180900
SEL8  
SPC WW 180900
NCZ000-VAZ000-CWZ000-181600-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 68
NWS STORM PREDICTION CENTER NORMAN OK
400 AM EST MON FEB 18 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       EXTREME NORTHEAST NORTH CAROLINA
       SOUTHEAST VIRGINIA
       COASTAL WATERS

EFFECTIVE THIS MONDAY MORNING FROM 400 AM UNTIL 1100 AM EST.

TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES WEST SOUTHWEST OF
ELIZABETH CITY NORTH CAROLINA TO 35 MILES EAST NORTHEAST OF
NORFOLK VIRGINIA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).

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.

OTHER WATCH INFORMATION...CONTINUE...WW 66...WW 67...

DISCUSSION...BROKEN SQLN WITH EMBEDDED SUPERCELLS OVER ERN NC
EXPECTED TO CONTINUE MOVING ENEWD...WITH ADDITIONAL DEVELOPMENT
LIKELY ON NRN END OF SYSTEM AS IT ENCOUNTERS INCREASINGLY RICH
MOISTURE ASSOCIATED WITH STRONG SLY LLJ.  ASCENT PROVIDED BY
PROGRESSIVE LARGE SCALE TROUGH TO THE WEST...AND INTENSE SHEAR
PROFILES...SUGGEST POTENTIAL FOR EMBEDDED SUPERCELLS WITH A RISK FOR
HIGH WIND/ISOLATED TORNADOES.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
350. MEAN STORM MOTION VECTOR 22050.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 18, 2:04 AM ESTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Brunswick, Carteret, Chowan and 22 more26 min
Feb 18, 2:30 AM ESTTornado WatchSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 26 more7 hr
Feb 18, 3:45 AM ESTMesoscale DiscussionSPCCamden, Chowan, Currituck, Gates, Hertford, Northampton and 2 more30 min
Feb 18, 6:18 AM ESTMesoscale DiscussionSPCBeaufort, Brunswick, Camden, Carteret, Chowan, Craven and 12 more57 min

Nearby

Tornado Watches in Virginia, 2008Tornado Watches in North Carolina, 2008Every tornado watch in 2008

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.