Alert archive / Arkansas / Mesoscale Discussions in 2021
Mesoscale Discussion 779
The Storm Prediction Center issued this mesoscale discussion at May 27, 2021, 9:27 PM CDT for 29 counties in Arkansas. It was in force for 93 min.
The area
The outline as issued.
The facts
- Issued
- May 27, 2021, 9:27 PM CDT (02:27 UTC)
- Expired
- May 27, 2021, 11:00 PM CDT
- In force
- 93 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 217
All 29 counties
Cleburne County, AR, Conway County, AR, Crawford County, AR, Faulkner County, AR, Franklin County, AR, Garland County, AR, Grant County, AR, Hot Spring County, AR, Independence County, AR, Jefferson County, AR, Johnson County, AR, Logan County, AR, Lonoke County, AR, Monroe County, AR, Montgomery County, AR, Perry 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, Stone County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Yell County, AR
The radar
The Little Rock radar (KLZK), 61 km from the middle of the area, began a volume at 02:26 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 nearest sounding before it
Little Rock, AR (KLZK), launched 00:00Z, 2.5 hours before the alert went out and 268 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
- 697 J/kg
- Mixed-layer CIN
- -11 J/kg
- Mixed-layer LCL
- 1539 m above ground
- 0-6 km bulk shear
- 29 kt
- 0-1 km storm-relative helicity
- 81 m²/s²
- 0-3 km storm-relative helicity
- 148 m²/s²
- Significant tornado parameter
- 0.1
- Supercell composite
- 2.8
The text
As transmitted.
395
ACUS11 KWNS 280227
SWOMCD
SPC MCD 280227
ARZ000-OKZ000-280400-
Mesoscale Discussion 0779
NWS Storm Prediction Center Norman OK
0927 PM CDT Thu May 27 2021
Areas affected...parts of central into northern Arkansas
Concerning...Severe Thunderstorm Watch 217...
Valid 280227Z - 280400Z
The severe weather threat for Severe Thunderstorm Watch 217
continues.
SUMMARY...Severe threat continues across Severe Thunderstorm Watch
#217. Damaging winds remains the primary threat with the stronger
storms, though some severe hail and a tornado cannot be ruled out.
DISCUSSION...An outflow-dominant MCS is entering Severe Thunderstorm
Watch #217. MRMS mosaic radar data shows 30 dBZ cores peaking around
35 kft with some of the strongest updrafts across far eastern OK
into western AR, with some severe hail possible with a strong storm
core in LeFlore County, OK. Given 1500+ J/kg MLCAPE ahead of the
MCS, storms are expected to maintain modest intensity for a couple
more hours, with damaging gusts and occasional marginally severe
hail being the main threats. While low-level shear remains
relatively modest across the watch area, a brief tornado cannot be
completely ruled out with any transient QLCS circulations that are
not undercut by outflow. Otherwise, storms are expected to gradually
weaken by around 06Z given the onset of boundary-layer
stabilization, and the tendency for storms to be well undercut by
outflow.
..Squitieri/Edwards.. 05/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MEG...LZK...SHV...TSA...
LAT...LON 34559459 35129453 35649442 35819405 35879297 35869220
35869171 35549118 35049108 34539116 34179159 34079248
34099371 34559459SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 27, 8:17 PM CDT | Mesoscale Discussion | SPC | Montgomery, Polk, Scott, Sebastian, Yell | 58 min |
Nearby
Mesoscale Discussions in Arkansas, 2021Every mesoscale discussion in 2021
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.