Alert archive / Virginia / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 124, NWS Baltimore/Washington

May 23, 2011Nelson County, Virginia

NWS Baltimore/Washington issued this severe thunderstorm warning at May 23, 2011, 6:45 PM EDT for Nelson County, Virginia. It was in force for 45 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
May 23, 2011, 6:45 PM EDT (22:45 UTC)
Expired
May 23, 2011, 7:30 PM EDT
In force
45 min
Issued by
NWS Baltimore/Washington
Area
Storm-based polygon

County Nelson County, VA

The radar

The Roanoke radar (KFCX), 149 km from the middle of the area, began a volume at 22:47 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.

IssuedProductOfficeLasted
May 23, 10:48 AM EDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 10.8 hours before the alert went out and 85 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 12:00Z on 2011-05-23Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 264 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, Roanoke, VA at 12:00Z on 2011-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 181 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
264 J/kg
Mixed-layer CIN
-138 J/kg
Mixed-layer LCL
632 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
181 m²/s²
0-3 km storm-relative helicity
183 m²/s²
Significant tornado parameter
0.0
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 Baltimore/Washington wrote its last area forecast discussion before this severe thunderstorm warning went out at May 23, 6:08 PM EDT, 37 minutes earlier.

Area forecast discussion, May 23, 6:08 PM EDT, 37 minutes before
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Hazardous weather outlook, May 23, 6:10 PM EDT, 35 minutes before
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In the hours before

Special weather statement, May 23, 5:32 PM EDT, 1 hour 13 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
532 PM EDT MON MAY 23 2011

VAZ051-502-232200-
CULPEPER VA-SOUTHERN FAUQUIER VA-
532 PM EDT MON MAY 23 2011

...STRONG THUNDERSTORM TO AFFECT CULPEPER AND SOUTHERN FAUQUIER
COUNTIES...

AT 531 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
STEVENSBURG IN EAST CENTRAL CULPEPER COUNTY...MOVING EAST AT 25 MPH.

LOCATIONS IMPACTED EXTREME EASTERN CULPEPER AND SOUTHERN FAUQUIER
COUNTIES...INCLUDE LIGNUM...SUMERDUCK...LOIS...MORRISVILLE AND
GOLDVEIN.

HEAVY RAIN WITH THIS STORM MAY REDUCE VISIBILITIES TO BELOW ONE MILE
AND MAY CAUSE PONDING OF WATER ON ROADWAYS.

SMALL HAIL AND WIND GUSTS TO 40 MPH CAN BE EXPECTED WITH THIS STORM.

&&

LAT...LON 3854 7762 3839 7764 3843 7795 3851 7796
TIME...MOT...LOC 2131Z 266DEG 20KT 3846 7788

SMZ
Special weather statement, May 23, 5:36 PM EDT, 1 hour 9 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
536 PM EDT MON MAY 23 2011

MDZ005-006-232200-
CARROLL MD-NORTHERN BALTIMORE MD-
536 PM EDT MON MAY 23 2011

...STRONG THUNDERSTORM TO AFFECT CARROLL AND NORTHERN BALTIMORE
COUNTIES...

AT 536 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM OVER
MILLERS...MOVING NORTHEAST AT 35 MPH.

LOCATIONS IMPACTED INCLUDE FREELAND AND MARYLAND LINE.

WIND GUSTS IN EXCESS OF 50 MPH AND SMALL HAIL CAN BE EXPECTED WITH
THIS STORM. WINDS THIS STRONG CAN BRING DOWN LARGE TREE BRANCHES.
TAKE SHELTER UNTIL THE STORM HAS PASSED.

&&

LAT...LON 3962 7690 3971 7695 3973 7692 3972 7659
TIME...MOT...LOC 2136Z 241DEG 28KT 3969 7684

SBK
Special weather statement, May 23, 5:39 PM EDT, 1 hour 6 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
539 PM EDT MON MAY 23 2011

MDZ005-006-010-011-232230-
CARROLL MD-NORTHERN BALTIMORE MD-HOWARD MD-SOUTHERN BALTIMORE MD-
539 PM EDT MON MAY 23 2011

...STRONG THUNDERSTORM TO AFFECT CARROLL...NORTHERN BALTIMORE...
HOWARD AND SOUTHERN BALTIMORE COUNTIES...

AT 540 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 2 MILES
NORTHWEST OF SYKESVILLE...MOVING EAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE ELDERSBURG...CARROLLTOWNE...OAKLAND...
LOUISVILLE...REISTERSTOWN...GLYNDON...OWINGS MILLS...HUNT VALLEY...
COCKEYSVILLE AND SPARKS.

HEAVY RAIN WITH THIS STORM MAY REDUCE VISIBILITIES TO BELOW ONE MILE
AND MAY CAUSE PONDING OF WATER ON ROADWAYS.

WIND GUSTS IN EXCESS OF 50 MPH AND SMALL HAIL CAN BE EXPECTED WITH
THIS STORM. WINDS THIS STRONG CAN BRING DOWN LARGE TREE BRANCHES.
TAKE SHELTER UNTIL THE STORM HAS PASSED.

&&

LAT...LON 3970 7664 3938 7646 3934 7701 3944 7710
TIME...MOT...LOC 2140Z 249DEG 22KT 3940 7697

SBK
Special weather statement, May 23, 5:57 PM EDT, 48 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
557 PM EDT MON MAY 23 2011

MDZ009-VAZ042-232245-
MONTGOMERY MD-LOUDOUN VA-
557 PM EDT MON MAY 23 2011

...STRONG THUNDERSTORM TO AFFECT MONTGOMERY AND LOUDOUN COUNTIES...

AT 557 PM EDT...DOPPLER RADAR INDICATED A STRONG THUNDERSTORM 2 MILES
NORTH OF LANSDOWNE...MOVING EAST AT 25 MPH.

LOCATIONS IMPACTED INCLUDE POOLESVILLE...DAWSONVILLE...DARNESTOWN...
NORTH POTOMAC...GAITHERSBURG...DERWOOD AND WASHINGTON GROVE.

THIS STORM IS PRODUCING FREQUENT CLOUD TO GROUND LIGHTNING. MOVE
INDOORS IMMEDIATELY FOR YOUR SAFETY. IF YOU CAN HEAR THUNDER...YOU
ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING.

HEAVY RAIN WITH THIS STORM MAY REDUCE VISIBILITIES TO BELOW ONE MILE
AND MAY CAUSE PONDING OF WATER ON ROADWAYS.

WIND GUSTS IN EXCESS OF 50 MPH AND SMALL HAIL CAN BE EXPECTED WITH
THIS STORM. WINDS THIS STRONG CAN BRING DOWN LARGE TREE BRANCHES.
TAKE SHELTER UNTIL THE STORM HAS PASSED.

&&

LAT...LON 3921 7702 3917 7700 3916 7698 3897 7700
      3897 7701 3900 7704 3895 7710 3900 7725
      3902 7725 3906 7733 3903 7736 3909 7756
      3917 7753 3925 7707
TIME...MOT...LOC 2157Z 274DEG 21KT 3912 7746

SBK
Local storm report, May 23, 6:15 PM EDT, 30 minutes before
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Local storm report, May 23, 6:34 PM EDT, 11 minutes before
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The office that day

Everything else NWS Baltimore/Washington issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 22, 8:10 PM EDTSpecial Weather StatementLWXCity of Harrisonburg35 min
May 22, 9:19 PM EDTSpecial Weather StatementLWXShenandoah26 min
May 22, 9:58 PM EDTSpecial Weather StatementLWXShenandoah32 min
May 22, 10:01 PM EDTSpecial Weather StatementLWXAugusta, Highland44 min
May 22, 10:23 PM EDTSevere Thunderstorm WarningLWXAugusta, City of Staunton52 min
May 22, 10:27 PM EDTSpecial Weather StatementLWXShenandoah, Warren48 min
May 22, 10:31 PM EDTSevere Thunderstorm WarningLWXHighland44 min
May 22, 10:49 PM EDTSpecial Weather StatementLWXRockingham, City of Harrisonburg41 min
May 22, 10:57 PM EDTSpecial Weather StatementLWXNelson48 min
May 22, 11:11 PM EDTSevere Thunderstorm WarningLWXAugusta, Rockingham, City of Harrisonburg49 min
May 22, 11:38 PM EDTSpecial Weather StatementLWXCity of Charlottesville37 min
May 23, 12:09 AM EDTSpecial Weather StatementLWXPage36 min
May 23, 12:13 AM EDTSpecial Weather StatementLWXFrederick32 min
May 23, 1:23 AM EDTSpecial Weather StatementLWXLoudoun37 min
May 23, 1:33 AM EDTSpecial Weather StatementLWXFairfax, Prince William, City of Fairfax, City of Manassas, City of Manassas Park27 min
May 23, 6:34 AM EDTCoastal Flood AdvisoryLWXArlington, Fairfax, King George, Stafford, City of Alexandria, City of Fairfax and 1 more29 hr
May 23, 3:18 PM EDTSpecial Weather StatementLWXFrederick42 min
May 23, 3:20 PM EDTSpecial Weather StatementLWXShenandoah40 min
May 23, 3:42 PM EDTSevere Thunderstorm WarningLWXFrederick31 min
May 23, 3:53 PM EDTSpecial Weather StatementLWXClarke, Frederick, City of Winchester52 min
May 23, 3:58 PM EDTSpecial Weather StatementLWXShenandoah, Warren47 min
May 23, 4:24 PM EDTSevere Thunderstorm WarningLWXClarke, Frederick, Loudoun51 min
May 23, 4:45 PM EDTSevere Thunderstorm WarningLWXCulpeper, Madison, Orange45 min
May 23, 5:12 PM EDTSevere Thunderstorm WarningLWXLoudoun48 min
May 23, 5:32 PM EDTSpecial Weather StatementLWXCulpeper28 min
May 23, 5:50 PM EDTSpecial Marine WarningLWX57 min
May 23, 6:18 PM EDTSpecial Marine WarningLWX40 min
May 23, 12:15 AM EDTSpecial Weather StatementLWXAllegany75 min
May 23, 2:00 AM EDTSpecial Weather StatementLWXMontgomery30 min
May 23, 4:37 PM EDTSpecial Weather StatementLWXWashington23 min
May 23, 5:36 PM EDTSpecial Weather StatementLWXCarroll24 min
May 23, 5:39 PM EDTSpecial Weather StatementLWXBaltimore51 min
May 23, 5:57 PM EDTSpecial Weather StatementLWXMontgomery48 min
May 23, 6:13 PM EDTSevere Thunderstorm WarningLWXHoward, Montgomery, Prince George's47 min
May 22, 11:14 PM EDTSpecial Weather StatementLWXGrant, Hardy, Pendleton46 min
May 23, 3:05 PM EDTSpecial Weather StatementLWXHampshire25 min

Nearby

Severe Thunderstorm Warnings in Virginia, 2011Every severe thunderstorm warning in 2011

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.