Alert archive / Arkansas / Mesoscale Discussions in 2018
Mesoscale Discussion 113
The Storm Prediction Center issued this mesoscale discussion at Mar 10, 2018, 5:57 PM CST for 40 counties in Arkansas; 9 counties in Mississippi. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 10, 2018, 5:57 PM CST (23:57 UTC)
- Expired
- Mar 10, 2018, 8:00 PM CST
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 49 counties
Arkansas County, AR, Bradley County, AR, Calhoun County, AR, Chicot County, AR, Clark County, AR, Cleveland County, AR, Conway County, AR, Crawford County, AR, Dallas County, AR, Desha County, AR, Drew County, AR, Faulkner County, AR, Franklin County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Howard County, AR, Jefferson County, AR, Johnson County, AR, Lincoln County, AR, Logan County, AR, Lonoke County, AR, Madison County, AR, Monroe County, AR, Montgomery County, AR, Newton County, AR, Ouachita County, AR, Perry County, AR, Phillips County, AR, Pike County, AR, Polk County, AR, Pope County, AR, Prairie County, AR, Pulaski County, AR, Saline County, AR, Scott County, AR, Sebastian County, AR, Van Buren County, AR, White County, AR, Yell County, AR, Bolivar County, MS, Coahoma County, MS, Grenada County, MS, Humphreys County, MS, Leflore County, MS, Quitman County, MS, Sunflower County, MS, Tallahatchie County, MS, Washington County, MS
The radar
The Little Rock radar (KLZK), 57 km from the middle of the area, began a volume at 23:56 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, 12.0 hours before the alert went out and 259 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
- 1807 m above ground
- 0-6 km bulk shear
- 47 kt
- 0-1 km storm-relative helicity
- 116 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
811
ACUS11 KWNS 102357
SWOMCD
SPC MCD 102357
MSZ000-ARZ000-OKZ000-110200-
Mesoscale Discussion 0113
NWS Storm Prediction Center Norman OK
0557 PM CST Sat Mar 10 2018
Areas affected...Central/Southern AR...Northwest MS
Concerning...Severe Thunderstorm Watch 7...
Valid 102357Z - 110200Z
The severe weather threat for Severe Thunderstorm Watch 7 continues.
SUMMARY...Severe hail as well as damaging wind gusts remain possible
for the next few hours across central/southern AR.
DISCUSSION...Recent radar trends have shown an increase of
southwesterly motion of the supercell moving through Logan county,
likely a result of both a transition to a more outflow-dominant
storm structure and influence from an upstream shortwave trough.
This transition has lead to a modest weakening in overall storm
strength, although the updraft currently remains strong enough to
produce severe hail (as evidenced by recent storm reports a MESH
over 1 inch). Current mesoanalysis estimates the downsteam airmass
is marginally unstable with MLCAPE around 500 J/kg. Expectation is
for a continued linear transition with storm motion along or very
near the warm front. As this occurs, the threat for severe hail will
diminish somewhat with some increase in the overall damaging wind
potential, at least for the next hour or two.
More cellular convection is also possible across northwest MS in the
vicinity of the warm front. Instability in this area is not
particularly strong but favorable shear may result in a few updrafts
capable of isolated severe hail. The need for an additional watch
within the next hour or two is unclear although trends will be
monitored closely.
..Mosier/Guyer.. 03/10/2018
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...JAN...LZK...SHV...TSA...
LAT...LON 35579464 36069371 35819258 33848959 32989069 33509269
34269440 35579464SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 10, 3:11 PM CST | Mesoscale Discussion | SPC | Clark, Cleveland, Conway, Crawford, Dallas, Faulkner and 20 more | 3 hr |
| Mar 10, 3:43 PM CST | Severe Thunderstorm Watch | SPC | Arkansas, Bradley, Calhoun, Clark, Cleveland, Conway and 30 more | 6 hr |
Nearby
Mesoscale Discussions in Arkansas, 2018Mesoscale Discussions in Mississippi, 2018Every mesoscale discussion in 2018
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.