Alert archive / Arkansas / Tornado Watches in 2009

Tornado Watch 82

March 27, 200933 counties in Arkansas; 19 parishes in Louisiana; 16 counties in Texas

The Storm Prediction Center issued this tornado watch at Mar 27, 2009, 6:35 PM CDT for 33 counties in Arkansas; 19 parishes in Louisiana; 16 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Mar 27, 2009, 6:35 PM CDT (23:35 UTC)
Expired
Mar 28, 2009, 2:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
70 kt
All 68 counties

Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Columbia County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Garland County, AR, Grant County, AR, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Lafayette County, AR, Lincoln County, AR, Little River County, AR, Lonoke County, AR, Miller County, AR, Monroe County, AR, Montgomery County, AR, Nevada County, AR, Ouachita County, AR, Pike County, AR, Polk County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Sevier County, AR, Union County, AR, Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, East Carroll Parish, LA, Jackson Parish, LA, Lincoln Parish, LA, Madison Parish, LA, Morehouse Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Red River Parish, LA, Richland Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, West Carroll Parish, LA, Winn Parish, LA, Angelina County, TX, Bowie County, TX, Camp County, TX, Cass County, TX, Cherokee County, TX, Gregg County, TX, Harrison County, TX, Marion County, TX, Morris County, TX, Nacogdoches County, TX, Panola County, TX, Rusk County, TX, Sabine County, TX, San Augustine County, TX, Shelby County, TX, Upshur County, TX

The radar

The Shreveport radar (KSHV), 121 km from the middle of the area, began a volume at 23:36 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Mar 27, 8:22 PM CDTSevere Thunderstorm WarningSHVBossier, Webster38 min
Mar 27, 9:09 PM CDTSevere Thunderstorm WarningLZKMontgomery, Pike, Polk21 min
Mar 27, 9:19 PM CDTTornado WarningLZKMontgomery, Pike41 min
Mar 27, 9:49 PM CDTSevere Thunderstorm WarningLZKGarland, Montgomery, Pike, Yell26 min
Mar 27, 9:58 PM CDTSevere Thunderstorm WarningSHVBienville, Jackson, Natchitoches, Winn62 min
Mar 27, 10:26 PM CDTSevere Thunderstorm WarningSHVCaldwell, Jackson, Lincoln, Ouachita, Union, Winn64 min
Mar 27, 10:59 PM CDTSevere Thunderstorm WarningJANMorehouse, Richland61 min
Mar 27, 11:06 PM CDTTornado WarningSHVOuachita39 min
Mar 27, 11:14 PM CDTTornado WarningJANMorehouse, Richland46 min
Mar 27, 11:44 PM CDTTornado WarningJANEast Carroll, Madison, Richland, West Carroll46 min
Mar 28, 12:15 AM CDTTornado WarningJANEast Carroll, West Carroll18 min
Mar 28, 12:32 AM CDTSevere Thunderstorm WarningJANEast Carroll43 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

Shreveport, LA (KSHV), launched 12:00Z, 11.6 hours before the alert went out and 115 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, Shreveport, LA at 12:00Z on 2009-03-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 142 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, Shreveport, LA at 12:00Z on 2009-03-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 square meters per square second.1939587897Sfc1 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
142 J/kg
Mixed-layer CIN
-191 J/kg
Mixed-layer LCL
516 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
35 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.5

Open this sounding in Storm Lab

The text

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

514 
WWUS20 KWNS 272342
SEL2  
SPC WW 272342
ARZ000-LAZ000-TXZ000-280700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 82
NWS STORM PREDICTION CENTER NORMAN OK
635 PM CDT FRI MAR 27 2009

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

       SOUTHERN ARKANSAS
       NORTHWEST LOUISIANA
       NORTHEAST TEXAS

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 635 PM
UNTIL 200 AM CDT.

TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 95 STATUTE
MILES EAST AND WEST OF A LINE FROM 15 MILES WEST NORTHWEST OF
LITTLE ROCK ARKANSAS TO 50 MILES WEST SOUTHWEST OF NATCHITOCHES
LOUISIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).

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 78...WW 79...WW 80...WW
81...

DISCUSSION...POWERFUL UPPER TROUGH AND ASSOCIATED 70-80 MID LEVEL
JET STREAK WILL CONTINUE TO SPREAD EAST ACROSS TX/OK AREAS THROUGH
TONIGHT AND LEND SUPPORT TO DEEP SURFACE CYCLOGENESIS FROM THE
ARKLATEX TO THE MS RIVER. AIR MASS AHEAD OF THIS PRONOUNCED SUPPORT
FOR STRONG UPWARD MOTION WAS MOIST AND SUFFICIENTLY UNSTABLE TO
SUPPORT ROBUST TSTM UPDRAFTS IN A REGIME CHARACTERIZED BY
STRENGTHENING DEEP-LAYER SHEAR AND INTENSE MESOSCALE FORCING NEAR
THE DEVELOPING LOW AND EWD ALONG WARM FRONT ACROSS SRN AR. CELLS
SHOULD CONTINUE TO GAIN STRENGTH NEAR THESE FEATURES...AS WELL AS
ALONG SURGING COLD FRONT NOW MOVING INTO ERN TX AND SERN OK. SHEAR
AND FORCING WILL BE MORE THAN ADEQUATE FOR UPDRAFT ROTATION AND
LONG-LIVED MESOCYCLONES. STORMS NEAR/EAST THE LOW CENTER...AND
TRACKING ALONG THE FRONT ACROSS AR WILL EXPERIENCE GREATEST LOW
LEVEL SHEAR AND HAVE THE POTENTIAL TO PRODUCE TORNADOES IN ADDITION
TO VERY LARGE HAIL. LINEAR FORCING WITH THE COLD FRONT MAY PROMOTE
EVENTUAL SQUALL LINE DEVELOPMENT WITH INCREASE IN WIDESPREAD WIND
THREAT POSSIBLY DEVELOPING LATER TONIGHT.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 24030.


...CARBIN

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 26, 9:28 PM CDTMesoscale DiscussionSPCHoward, Montgomery, Polk, Scott, Sevier62 min
Mar 27, 12:33 PM CDTMesoscale DiscussionSPCHempstead, Howard, Lafayette, Little River, Miller, Sevier57 min
Mar 27, 12:58 PM CDTTornado WatchSPCHoward, Little River, Miller, Sevier7 hr
Mar 27, 3:34 PM CDTMesoscale DiscussionSPCHoward, Little River, Miller, Sevier56 min
Mar 27, 5:53 PM CDTMesoscale DiscussionSPCAshley, Bradley, Calhoun, Chicot, Clark, Cleveland and 16 more97 min
Mar 26, 9:13 PM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Caldwell and 16 more92 min
Mar 26, 11:53 PM CDTMesoscale DiscussionSPCAscension, Assumption, Jefferson, Lafourche, Livingston, Orleans and 7 more97 min
Mar 27, 12:48 AM CDTTornado WatchSPCAscension, Assumption, Iberville, Jefferson, Lafourche, Livingston and 10 more7 hr
Mar 27, 2:23 AM CDTMesoscale DiscussionSPCAssumption, Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard and 3 more67 min
Mar 27, 4:37 AM CDTMesoscale DiscussionSPCJefferson, Lafourche, Plaquemines, Saint Bernard53 min
Mar 27, 6:35 AM CDTMesoscale DiscussionSPCJefferson, Plaquemines55 min
Mar 27, 2:34 PM CDTMesoscale DiscussionSPCAllen, Avoyelles, Beauregard, Evangeline, Rapides, Saint Landry and 1 more56 min
Mar 27, 2:54 PM CDTTornado WatchSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, East Baton Rouge and 14 more6 hr
Mar 27, 4:16 PM CDTTornado WatchSPCCaldwell, Catahoula, Concordia, Franklin, Grant, LaSalle and 1 more4 hr
Mar 27, 4:49 PM CDTTornado WatchSPCCameron3 hr
Mar 27, 6:18 PM CDTMesoscale DiscussionSPCLivingston, Saint Helena, Saint Tammany, Tangipahoa, Washington57 min
Mar 26, 7:32 PM CDTSevere Thunderstorm WatchSPCCooke, Denton, Fannin, Grayson, Jack, Montague and 1 more4 hr
Mar 26, 11:34 PM CDTMesoscale DiscussionSPCDallam, Hartley, Moore, Oldham, Sherman4 hr
Mar 27, 2:55 AM CDTMesoscale DiscussionSPCArmstrong, Carson, Dallam, Deaf Smith, Hansford, Hartley and 9 more4 hr
Mar 27, 8:04 AM CDTMesoscale DiscussionSPCCollingsworth, Donley, Gray, Hemphill, Lipscomb, Ochiltree and 2 more4 hr
Mar 27, 10:24 AM CDTMesoscale DiscussionSPCAnderson, Angelina, Austin, Bastrop, Bell, Brazoria and 43 more96 min
Mar 27, 11:48 AM CDTSevere Thunderstorm WatchSPCAustin, Brazos, Burleson, Chambers, Grimes, Hardin and 16 more5 hr
Mar 27, 12:30 PM CDTMesoscale DiscussionSPCCarson, Childress, Collingsworth, Donley, Gray, Hansford and 8 more6 hr
Mar 27, 3:43 PM CDTMesoscale DiscussionSPCChambers, Hardin, Harris, Jasper, Jefferson, Liberty and 6 more62 min

Nearby

Tornado Watches in Arkansas, 2009Tornado Watches in Louisiana, 2009Tornado Watches in Texas, 2009Every tornado watch in 2009

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.