Alert archive / Mississippi / Tornado Watches in 2009

Tornado Watch 774

October 22, 200928 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Oct 22, 2009, 6:55 PM CDT for 28 counties in Mississippi. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Oct 22, 2009, 6:55 PM CDT (23:55 UTC)
Expired
Oct 22, 2009, 9:46 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 28 counties

Attala County, MS, Bolivar County, MS, Carroll County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Jefferson Davis County, MS, Lamar County, MS, Lawrence County, MS, Leake County, MS, Leflore County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Montgomery County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Sunflower County, MS, Washington County, MS, Yazoo County, MS

The radar

The Jackson/Brandon,MS radar (KDGX), 55 km from the middle of the area, began a volume at 23:59 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
20%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
10%
One or more gusts of 65 knots or more
10%
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
30%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Oct 22, 6:55 PM CDTSevere Thunderstorm WarningJANCopiah, Franklin, Jefferson, Lincoln65 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

Jackson, MS (KJAN), launched 12:00Z, 11.9 hours before the alert went out and 46 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, Jackson, MS at 12:00Z on 2009-10-22Temperature 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, Jackson, MS at 12:00Z on 2009-10-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 194 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
843 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
194 m²/s²
0-3 km storm-relative helicity
250 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 22, 11:27 AM CDTMesoscale DiscussionSPCAdams, Amite, Claiborne, Copiah, Franklin, Hinds and 5 more93 min
Oct 22, 11:58 AM CDTTornado WatchSPCAdams, Amite, Claiborne, Franklin, Issaquena, Jefferson and 3 more7 hr
Oct 22, 3:36 PM CDTMesoscale DiscussionSPCAdams, Amite, Claiborne, Franklin, Issaquena, Jefferson and 2 more114 min
Oct 22, 4:35 PM CDTTornado WatchSPCHancock, Harrison, Jackson, Pearl River, Pike, Walthall4 hr
Oct 22, 6:26 PM CDTMesoscale DiscussionSPCAdams, Amite, Bolivar, Carroll, Claiborne, Coahoma and 24 more34 min

Nearby

Tornado Watches in Mississippi, 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.