Alert archive / Virginia / Severe Thunderstorm Warnings in 2010

Severe Thunderstorm Warning 227, NWS Blacksburg, VA

July 20, 20105 counties in Virginia

NWS Blacksburg, VA issued this severe thunderstorm warning at Jul 20, 2010, 2:24 PM EDT for 5 counties in Virginia. It was in force for 66 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: Jul 20, 2010, 2:24 PM EDT (18:24 UTC)
Expired: Jul 20, 2010, 3:30 PM EDT
In force: 66 min
Issued by: NWS Blacksburg, VA
Area: Storm-based polygon

Counties City of Radford, VA, Craig County, VA, Giles County, VA, Montgomery County, VA, Pulaski County, VA

The radar

The Roanoke radar (KFCX), 32 km from the middle of the area, began a volume at 18:23 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
Jul 20, 1:29 PM EDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 6.4 hours before the alert went out and 90 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: 922 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 707 m above ground
0-6 km bulk shear: 24 kt
0-1 km storm-relative helicity: 98 m²/s²
0-3 km storm-relative helicity: 104 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.8

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 Blacksburg, VA wrote its last area forecast discussion before this severe thunderstorm warning went out at Jul 20, 10:53 AM EDT, 3 hours 31 minutes earlier.

Area forecast discussion, Jul 20, 10:53 AM EDT, 3 hours 31 minutes before

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Hazardous weather outlook, Jul 20, 2:03 PM EDT, 21 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
203 PM EDT TUE JUL 20 2010

NCZ001>003-018-019-VAZ007-009>020-022>024-032>035-WVZ042>045-211815-
ASHE-ALLEGHANY NC-SURRY-WATAUGA-WILKES-TAZEWELL-SMYTH-BLAND-GILES-
WYTHE-PULASKI-MONTGOMERY-GRAYSON-CARROLL-FLOYD-CRAIG-ALLEGHANY VA-
BATH-ROANOKE-BOTETOURT-ROCKBRIDGE-PATRICK-FRANKLIN-BEDFORD-AMHERST-
MERCER-SUMMERS-MONROE-GREENBRIER-
203 PM EDT TUE JUL 20 2010

...SEVERE THUNDERSTORM WATCH 502 IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH
CAROLINA...NORTHWEST NORTH CAROLINA...CENTRAL VIRGINIA...SOUTH
CENTRAL VIRGINIA...SOUTHWEST VIRGINIA...WEST CENTRAL VIRGINIA AND
SOUTHEAST WEST VIRGINIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SEVERE THUNDERSTORM WATCH.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING. THE PRIMARY THREAT FROM ANY SEVERE STORMS IS DAMAGING
WINDS. VERY HEAVY RAIN IS ALSO LIKELY WITH ANY OF THE STORMS
TODAY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THUNDERSTORMS COULD BE SEVERE AND MAY PRODUCE DAMAGING WIND GUSTS
WEDNESDAY AND THURSDAY. NUMEROUS STORMS MOVING OVER THE SAME AREA
MAY LEAD TO FLASH FLOODING.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

NCZ004>006-020-VAZ043>047-058-059-211815-
STOKES-ROCKINGHAM-CASWELL-YADKIN-HENRY-PITTSYLVANIA-CAMPBELL-
APPOMATTOX-BUCKINGHAM-HALIFAX-CHARLOTTE-
203 PM EDT TUE JUL 20 2010

...SEVERE THUNDERSTORM WATCH 502 IN EFFECT UNTIL 8 PM EDT THIS
EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH
CAROLINA...NORTHWEST NORTH CAROLINA...CENTRAL VIRGINIA AND SOUTH
CENTRAL VIRGINIA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   SEVERE THUNDERSTORM WATCH.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING. THE PRIMARY THREAT FROM ANY SEVERE STORMS IS DAMAGING
WINDS. VERY HEAVY RAIN IS ALSO LIKELY WITH ANY OF THE STORMS
TODAY.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THUNDERSTORMS COULD BE SEVERE AND MAY PRODUCE DAMAGING WIND GUSTS
WEDNESDAY AND THURSDAY. NUMEROUS STORMS MOVING OVER THE SAME AREA
MAY LEAD TO FLASH FLOODING.

ON SATURDAY...THE COMBINATION OF THE TEMPERATURE AND HUMIDITY MAY CAUSE
THE HEAT INDEX TO BE BETWEEN 105 AND 108 DEGREES FOR A FEW HOURS
LATE IN THE AFTERNOON.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

In the hours before

Special weather statement, Jul 20, 11:54 AM EDT, 2 hours 30 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1154 AM EDT TUE JUL 20 2010

VAZ044-058-201700-
HALIFAX VA-PITTSYLVANIA VA-
1154 AM EDT TUE JUL 20 2010

...A STRONG THUNDERSTORM WILL AFFECT HALIFAX AND PITTSYLVANIA
COUNTIES...

AT 1152 AM EDT...A STRONG THUNDERSTORM WAS LOCATED NEAR RIDGEWAY...
MOVING EAST AT 20 MPH.

WIND GUSTS TO 30 MPH ARE POSSIBLE WITH THIS STORM. VERY HEAVY RAIN
WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO POND ON ROADS AND
QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS.

THIS STORM WILL BE NEAR LEDA AROUND NOON...CRYSTAL HILL AROUND 1230
PM...SCOTTSBURG AROUND 1245 PM AND MT LAUREL AROUND 100 PM.

LISTEN TO NOAA WEATHER RADIO OR YOUR FAVORITE MEDIA OUTLET FOR LATER
UPDATES OR POSSIBLE WARNINGS.

LAT...LON 3675 7868 3674 7868 3676 7923 3694 7924
      3699 7881 3696 7878 3699 7878 3699 7875
      3693 7873 3693 7875 3690 7871 3676 7867

AMS

Local storm report, Jul 20, 11:56 AM EDT, 2 hours 28 minutes before

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Special weather statement, Jul 20, 12:57 PM EDT, 1 hour 27 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1257 PM EDT TUE JUL 20 2010

VAZ007-201800-
TAZEWELL VA-
1257 PM EDT TUE JUL 20 2010

...A STRONG THUNDERSTORM WILL AFFECT TAZEWELL COUNTY...

AT 1256 PM EDT...A STRONG THUNDERSTORM WAS LOCATED NEAR JEWELL
RIDGE...MOVING EAST AT 20 MPH.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM. VERY HEAVY RAIN
WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO POND ON ROADS AND
QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS. EXPECT FREQUENT
CLOUD TO GROUND LIGHTNING FROM THIS STORM. DO NOT STAY IN THE OPEN OR
SEEK SHELTER UNDER TREES WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN
A THUNDERSTORM APPROACHES.

THIS STORM WILL BE NEAR BANDY AROUND 115 PM...AMONATE AROUND 130
PM...TAZEWELL AROUND 145 PM AND TIPTOP AROUND 200 PM.

THE PUBLIC IS ENCOURAGED TO RELAY REPORTS OF STRONG WINDS...HAIL OR
FLOODING TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
1...8 6 6...2 1 5...4 3 2 4...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3719 8183 3720 8178 3725 8175 3721 8167
      3721 8154 3726 8149 3728 8142 3730 8140
      3731 8132 3725 8124 3715 8133 3714 8132
      3706 8138 3704 8145 3702 8145 3697 8178
      3713 8191

AMS

Local storm report, Jul 20, 1:04 PM EDT, 1 hour 20 minutes before

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Special weather statement, Jul 20, 2:06 PM EDT, 18 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
206 PM EDT TUE JUL 20 2010

VAZ009>013-WVZ042>044-201900-
BLAND VA-GILES VA-MERCER WV-MONROE WV-PULASKI VA-SMYTH VA-SUMMERS WV-
WYTHE VA-
206 PM EDT TUE JUL 20 2010

...STRONG THUNDERSTORMS WILL AFFECT BLAND...GILES...MERCER...
MONROE...PULASKI...SMYTH...SUMMERS AND WYTHE COUNTIES...

AT 202 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 6 MILES
NORTH OF MATOAKA TO 5 MILES EAST OF ROCKY GAP TO 5 MILES NORTHEAST OF
SUGAR GROVE...MOVING EAST AT 35 MPH.

WIND GUSTS TO 50 MPH ARE POSSIBLE WITH THESE STORMS.

THESE STORMS WILL BE NEAR FLAT TOP AROUND 215 PM...JUMPING BRANCH
AROUND 230 PM...BLUESTONE STATE PARK AROUND 245 PM AND DRAPER AROUND
300 PM.

THE PUBLIC IS ENCOURAGED TO RELAY REPORTS OF STRONG WINDS...HAIL OR
FLOODING TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
1...8 6 6...2 1 5...4 3 2 4...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3673 8149 3719 8109 3743 8130 3749 8127
      3752 8121 3757 8120 3760 8109 3765 8107
      3767 8102 3775 8071 3743 8046 3737 8045
      3727 8053 3724 8061 3721 8062 3719 8058
      3694 8076

AMS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 11:54 AM EDT	Special Weather Statement	RNK	Halifax	66 min
Jul 20, 12:57 PM EDT	Special Weather Statement	RNK	Tazewell	63 min
Jul 20, 2:06 PM EDT	Special Weather Statement	RNK	Bland, Giles, Pulaski, Wythe	54 min
Jul 20, 2:47 PM EDT	Severe Thunderstorm Warning	RNK	Floyd, Montgomery, Pulaski	58 min
Jul 20, 2:55 PM EDT	Special Weather Statement	RNK	Henry, Patrick	65 min
Jul 20, 3:25 PM EDT	Special Weather Statement	RNK	Botetourt	35 min
Jul 20, 3:32 PM EDT	Special Weather Statement	RNK	Patrick	58 min
Jul 20, 3:47 PM EDT	Severe Thunderstorm Warning	RNK	Henry, Patrick	58 min
Jul 20, 4:06 PM EDT	Severe Thunderstorm Warning	RNK	Amherst, Bedford, Campbell, Rockbridge, City of Buena Vista, City of Lexington and 1 more	54 min
Jul 20, 4:15 PM EDT	Severe Thunderstorm Warning	RNK	Halifax, Pittsylvania, City of Danville	60 min
Jul 20, 5:00 PM EDT	Special Weather Statement	RNK	Appomattox, Buckingham	60 min
Jul 20, 5:09 PM EDT	Severe Thunderstorm Warning	RNK	Appomattox, Buckingham	54 min
Jul 20, 5:14 PM EDT	Severe Thunderstorm Warning	RNK	Charlotte, Halifax, Pittsylvania, City of Danville	61 min
Jul 20, 5:19 PM EDT	Severe Thunderstorm Warning	RNK	Alleghany, Bath	56 min
Jul 20, 3:12 PM EDT	Special Weather Statement	RNK	Yadkin	63 min
Jul 20, 4:44 PM EDT	Special Weather Statement	RNK	Caswell, Rockingham	61 min
Jul 20, 4:55 PM EDT	Severe Thunderstorm Warning	RNK	Caswell, Rockingham	65 min
Jul 20, 7:30 PM EDT	Special Weather Statement	RNK	Ashe	45 min
Jul 20, 4:20 PM EDT	Special Weather Statement	RNK	Greenbrier	55 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2010 Every severe thunderstorm warning in 2010

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.