Alert archive / Arkansas / Severe Thunderstorm Watches in 2017
Severe Thunderstorm Watch 154
The Storm Prediction Center issued this severe thunderstorm watch at Apr 21, 2017, 10:04 AM CDT for 20 counties in Arkansas; 17 counties in Oklahoma. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 21, 2017, 10:04 AM CDT (15:04 UTC)
- Expired
- Apr 21, 2017, 3:00 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 65 kt
All 37 counties
Clark County, AR, Crawford County, AR, Franklin County, AR, Garland County, AR, Hot Spring County, AR, Howard County, AR, Johnson County, AR, Little River County, AR, Logan County, AR, Madison County, AR, Montgomery County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Scott County, AR, Sebastian County, AR, Sevier County, AR, Washington County, AR, Yell County, AR, Adair County, OK, Cherokee County, OK, Choctaw County, OK, Creek County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, McIntosh County, OK, Muskogee County, OK, Okfuskee County, OK, Okmulgee County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK
The radar
The Western Arkansas radar (KSRX), 87 km from the middle of the area, began a volume at 15:08 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 70%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 90%
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 |
|---|---|---|---|---|
| Apr 21, 10:08 AM CDT | Severe Thunderstorm Warning | TSA | Okfuskee, Okmulgee | 67 min |
| Apr 21, 11:00 AM CDT | Severe Thunderstorm Warning | TSA | McIntosh, Muskogee, Okfuskee, Okmulgee, Pittsburg | 45 min |
| Apr 21, 11:18 AM CDT | Severe Thunderstorm Warning | TSA | Cherokee, Mayes, Muskogee, Okmulgee, Rogers, Tulsa and 1 more | 42 min |
| Apr 21, 11:39 AM CDT | Severe Thunderstorm Warning | TSA | Cherokee, Haskell, Latimer, McIntosh, Muskogee, Pittsburg and 1 more | 51 min |
| Apr 21, 11:51 AM CDT | Severe Thunderstorm Warning | TSA | Cherokee, Delaware, Mayes, Muskogee, Wagoner | 39 min |
| Apr 21, 11:53 AM CDT | Flash Flood Warning | TSA | Creek, Rogers, Tulsa, Wagoner | 3 hr |
| Apr 21, 12:10 PM CDT | Severe Thunderstorm Warning | TSA | Haskell, Latimer, LeFlore, Pushmataha | 35 min |
| Apr 21, 12:16 PM CDT | Severe Thunderstorm Warning | TSA | Crawford, Sebastian, Washington | 44 min |
| Apr 21, 12:38 PM CDT | Severe Thunderstorm Warning | TSA | Franklin, Sebastian | 52 min |
| Apr 21, 1:24 PM CDT | Severe Thunderstorm Warning | LZK | Logan, Scott, Yell | 51 min |
| Apr 21, 2:49 PM CDT | Severe Thunderstorm Warning | TSA | Creek, Tulsa | 41 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
Springfield, MO (KSGF), launched 12:00Z, 3.1 hours before the alert went out and 228 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 637 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- -171 m²/s²
- 0-3 km storm-relative helicity
- -150 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 21, 9:45 AM CDT | Mesoscale Discussion | SPC | Crawford, Franklin, Garland, Howard, Johnson, Logan and 12 more | 2 hr |
| Apr 21, 1:12 PM CDT | Mesoscale Discussion | SPC | Arkansas, Cleburne, Conway, Crawford, Crittenden, Cross and 28 more | 93 min |
| Apr 21, 3:09 PM CDT | Mesoscale Discussion | SPC | Hempstead, Howard, Lafayette, Little River, Miller, Pike and 2 more | 2 hr |
| Apr 21, 3:54 PM CDT | Mesoscale Discussion | SPC | Benton, Boone, Carroll, Crawford, Franklin, Johnson and 8 more | 66 min |
| Apr 21, 4:40 PM CDT | Tornado Watch | SPC | Hempstead, Howard, Little River, Logan, Miller, Montgomery and 6 more | 8 hr |
| Apr 20, 9:33 PM CDT | Severe Thunderstorm Watch | SPC | Beckham, Blaine, Caddo, Canadian, Carter, Cleveland and 20 more | 7 hr |
| Apr 20, 11:30 PM CDT | Mesoscale Discussion | SPC | Beckham, Blaine, Caddo, Canadian, Carter, Cleveland and 19 more | 60 min |
| Apr 21, 3:44 AM CDT | Mesoscale Discussion | SPC | Beckham, Blaine, Caddo, Canadian, Carter, Cleveland and 26 more | 2 hr |
| Apr 21, 4:20 AM CDT | Severe Thunderstorm Watch | SPC | Alfalfa, Atoka, Beaver, Beckham, Blaine, Bryan and 42 more | 8 hr |
| Apr 21, 7:54 AM CDT | Mesoscale Discussion | SPC | Alfalfa, Beckham, Blaine, Caddo, Canadian, Carter and 27 more | 2 hr |
Nearby
Severe Thunderstorm Watches in Arkansas, 2017Severe Thunderstorm Watches in Oklahoma, 2017Every severe thunderstorm watch in 2017
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.