Alert archive / Arkansas / Mesoscale Discussions in 2017
Mesoscale Discussion 697
The Storm Prediction Center issued this mesoscale discussion at May 11, 2017, 2:49 PM CDT for 4 states. It was in force for 116 min.
The area
The outline as issued.
The facts
- Issued
- May 11, 2017, 2:49 PM CDT (19:49 UTC)
- Expired
- May 11, 2017, 4:45 PM CDT
- In force
- 116 min
- Issued by
- the Storm Prediction Center
All 64 counties
Baxter County, AR, Benton County, AR, Boone County, AR, Carroll County, AR, Clark County, AR, Cleburne County, AR, Conway County, AR, Crawford County, AR, Faulkner County, AR, Franklin County, AR, Fulton County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Johnson County, AR, Logan County, AR, Lonoke County, AR, Madison County, AR, Marion County, AR, Montgomery County, AR, Newton County, AR, Perry County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Pulaski County, AR, Saline 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, Yell County, AR, Cherokee County, KS, Barry County, MO, Christian County, MO, Dade County, MO, Douglas County, MO, Greene County, MO, Howell County, MO, Jasper County, MO, Lawrence County, MO, McDonald County, MO, Newton County, MO, Oregon County, MO, Ozark County, MO, Stone County, MO, Taney County, MO, Texas County, MO, Webster County, MO, Wright County, MO, Adair County, OK, Cherokee County, OK, Delaware County, OK, LeFlore County, OK, Ottawa County, OK, Sequoyah County, OK
The radar
The Little Rock radar (KLZK), 113 km from the middle of the area, began a volume at 19:50 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 watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Springfield, MO (KSGF), launched 12:00Z, 7.8 hours before the alert went out and 155 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
- 1011 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 74 m²/s²
- 0-3 km storm-relative helicity
- 46 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
504
ACUS11 KWNS 111950
SWOMCD
SPC MCD 111949
ARZ000-MOZ000-OKZ000-KSZ000-112145-
Mesoscale Discussion 0697
NWS Storm Prediction Center Norman OK
0249 PM CDT Thu May 11 2017
Areas affected...Far Eastern Oklahoma...Arkansas...Far Southeast
Kansas...Southern Missouri
Concerning...Severe Thunderstorm Watch 208...
Valid 111949Z - 112145Z
The severe weather threat for Severe Thunderstorm Watch 208
continues.
SUMMARY...A severe threat is expected to develop across parts of far
eastern Oklahoma, much of Arkansas and into southern Missouri. Large
hail and wind damage are expected to be the primary threats. A new
weather watch will likely be needed to the east of WW 208 within the
hour.
DISCUSSION...The latest surface analysis shows a 1008 mb low in
central Oklahoma with a moist airmass located to the east of the low
across eastern Oklahoma and Arkansas. Surface dewpoints across this
area are generally in the mid to upper 60s F with the RAP estimating
MLCAPE values in the 2000 to 3000 J/kg range. Severe thunderstorms
are ongoing in the central part of WW 208 just to the west of where
the strongest instability is analyzed. The wind shear environment in
the vicinity of these storms is sampled well by the Tulsa WSR-99D
VWP which shows 0-6 km shear of 50 kt and some veering of winds with
height in the lowest 2 km AGL. This combined with 700-500 mb lapse
rates near 8.0 C/km will support supercells with large hail.
Supercells should also be associated with a wind damage threat. This
convection is forecast to maintain a severe threat, moving
northeastward into southwest Missouri. Thunderstorms will also
likely intensify southward across western and central Arkansas over
the next couple of hours. Moderate to strong deep-layer shear and
steep mid-level lapse rates in this area will also make supercells
with large hail possible. Short bowing line segments may also
develop and be accompanied by a wind damage threat.
..Broyles.. 05/11/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...LZK...SGF...SHV...TSA...
LAT...LON 37369146 37469476 36109518 34469459 33959387 33929273
34649173 35779104 37369146SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 11, 12:56 PM CDT | Severe Thunderstorm Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 8 hr |
| May 11, 1:37 PM CDT | Mesoscale Discussion | SPC | Hempstead, Howard, Lafayette, Little River, Miller, Sevier | 2 hr |
| May 11, 2:43 PM CDT | Severe Thunderstorm Watch | SPC | Columbia, Hempstead, Howard, Lafayette, Little River, Miller and 3 more | 9 hr |
| May 11, 3:17 PM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Baxter, Boone, Bradley, Calhoun, Clark and 45 more | 7 hr |
| May 11, 5:49 PM CDT | Mesoscale Discussion | SPC | Arkansas, Baxter, Boone, Bradley, Calhoun, Carroll and 56 more | 56 min |
| May 11, 6:07 PM CDT | Mesoscale Discussion | SPC | Benton, Washington | 83 min |
| May 11, 11:44 AM CDT | Mesoscale Discussion | SPC | Barber, Butler, Chautauqua, Comanche, Cowley, Elk and 6 more | 3 hr |
Nearby
Mesoscale Discussions in Arkansas, 2017Mesoscale Discussions in Missouri, 2017Mesoscale Discussions in Oklahoma, 2017Every mesoscale discussion 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.