Alert archive / Arkansas / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 38
The Storm Prediction Center issued this severe thunderstorm watch at Mar 4, 2011, 6:50 PM CST for 29 counties in Arkansas; 9 counties in Illinois; 27 counties in Missouri. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 4, 2011, 6:50 PM CST (00:50 UTC)
- Expired
- Mar 5, 2011, 1:56 AM CST
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 65 counties
Baxter County, AR, Benton County, AR, Boone County, AR, Carroll County, AR, Cleburne County, AR, Conway County, AR, Crawford County, AR, Franklin County, AR, Fulton County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Johnson County, AR, Logan County, AR, Madison County, AR, Marion County, AR, Newton County, AR, Perry County, AR, Pope County, AR, Scott County, AR, Searcy County, AR, Sebastian County, AR, Sharp County, AR, Stone County, AR, Van Buren County, AR, Washington County, AR, White County, AR, Woodruff County, AR, Yell County, AR, Bond County, IL, Clinton County, IL, Fayette County, IL, Madison County, IL, Marion County, IL, Monroe County, IL, Randolph County, IL, Saint Clair County, IL, Washington County, IL, Barry County, MO, Christian County, MO, City of Saint Louis, MO, Crawford County, MO, Dent County, MO, Douglas County, MO, Franklin County, MO, Howell County, MO, Iron County, MO, Jefferson County, MO, Laclede County, MO, Madison County, MO, Oregon County, MO, Ozark County, MO, Phelps County, MO, Pulaski County, MO, Reynolds County, MO, Saint Francois County, MO, Saint Louis County, MO, Sainte Genevieve County, MO, Shannon County, MO, Stone County, MO, Taney County, MO, Texas County, MO, Washington County, MO, Webster County, MO, Wright County, MO
The radar
The St Louis radar (KLSX), 149 km from the middle of the area, began a volume at 00:53 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
- 5%
- Ten or more severe wind reports
- 20%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
11 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 4, 7:00 PM CST | Severe Thunderstorm Warning | SGF | Laclede, Phelps, Pulaski, Texas | 45 min |
| Mar 4, 7:50 PM CST | Severe Thunderstorm Warning | TSA | Carroll, Madison | 40 min |
| Mar 4, 7:52 PM CST | Severe Thunderstorm Warning | SGF | Douglas, Ozark, Taney, Texas, Wright | 53 min |
| Mar 4, 8:40 PM CST | Severe Thunderstorm Warning | LZK | Boone, Newton | 50 min |
| Mar 4, 8:42 PM CST | Flash Flood Warning | SGF | Christian, Douglas, Taney, Webster, Wright | 6 hr |
| Mar 4, 9:43 PM CST | Severe Thunderstorm Warning | LZK | Baxter, Marion | 47 min |
| Mar 4, 10:20 PM CST | Severe Thunderstorm Warning | LZK | Baxter, Fulton, Izard, Marion | 40 min |
| Mar 4, 10:52 PM CST | Severe Thunderstorm Warning | LZK | Fulton, Izard | 38 min |
| Mar 4, 11:02 PM CST | Severe Thunderstorm Warning | LZK | Baxter, Searcy, Stone | 43 min |
| Mar 4, 11:29 PM CST | Severe Thunderstorm Warning | LZK | Fulton, Izard, Sharp | 46 min |
| Mar 5, 12:56 AM CST | Flash Flood Warning | LZK | Cleburne, Conway, Faulkner, Independence, Izard, Stone and 1 more | 3 hr |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Springfield, MO (KSGF), launched 00:00Z, 0.8 hours before the alert went out and 214 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.
- Mixed-layer CAPE
- 284 J/kg
- Mixed-layer CIN
- -42 J/kg
- Mixed-layer LCL
- 571 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 14 m²/s²
- 0-3 km storm-relative helicity
- 134 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 4, 6:22 PM CST | Mesoscale Discussion | SPC | Baxter, Boone, Fulton, Marion | 53 min |
| Mar 4, 10:48 PM CST | Mesoscale Discussion | SPC | Clay, Cleburne, Independence, Jackson, Lawrence, Randolph and 2 more | 87 min |
Nearby
Severe Thunderstorm Watches in Arkansas, 2011Severe Thunderstorm Watches in Missouri, 2011Severe Thunderstorm Watches in Illinois, 2011Every severe thunderstorm watch 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.