Alert archive / Arkansas / Tornado Watches in 2020

Tornado Watch 458

August 27, 202032 counties in Arkansas; 22 counties in Mississippi

The Storm Prediction Center issued this tornado watch at Aug 27, 2020, 3:47 PM CDT for 32 counties in Arkansas; 22 counties in Mississippi. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Aug 27, 2020, 3:47 PM CDT (20:47 UTC)
Expired
Aug 27, 2020, 11:40 PM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
0.5 in
Strongest gust expected
50 kt
All 54 counties

Arkansas County, AR, Clay County, AR, Cleburne County, AR, Craighead County, AR, Crittenden County, AR, Cross County, AR, Desha County, AR, Faulkner County, AR, Fulton County, AR, Grant County, AR, Greene County, AR, Independence County, AR, Izard County, AR, Jackson County, AR, Jefferson County, AR, Lawrence County, AR, Lee County, AR, Lincoln County, AR, Lonoke County, AR, Mississippi County, AR, Monroe County, AR, Phillips County, AR, Poinsett County, AR, Prairie County, AR, Pulaski County, AR, Randolph County, AR, Saline County, AR, Sharp County, AR, St. Francis County, AR, Stone County, AR, White County, AR, Woodruff County, AR, Bolivar County, MS, Calhoun County, MS, Carroll County, MS, Coahoma County, MS, DeSoto County, MS, Grenada County, MS, Holmes County, MS, Humphreys County, MS, Lafayette County, MS, Leflore County, MS, Marshall County, MS, Montgomery County, MS, Panola County, MS, Quitman County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Tate County, MS, Tunica County, MS, Washington County, MS, Yalobusha County, MS, Yazoo County, MS

The radar

The Little Rock radar (KLZK), 114 km from the middle of the area, began a volume at 20:47 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
5%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
20%

Warnings issued inside it

39 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Aug 27, 3:49 PM CDTTornado WarningLZKArkansas, Lonoke, Prairie17 min
Aug 27, 4:03 PM CDTFlash Flood WarningLZKArkansas, Desha, Grant, Jefferson, Lonoke, Pulaski and 1 more4 hr
Aug 27, 4:13 PM CDTTornado WarningLZKArkansas, Desha, Monroe34 min
Aug 27, 4:17 PM CDTTornado WarningMEGPhillips25 min
Aug 27, 4:19 PM CDTFlash Flood WarningLZKArkansas, Faulkner, Hot Spring, Lonoke, Prairie, Pulaski and 1 more4 hr
Aug 27, 5:20 PM CDTTornado WarningMEGLee, Phillips25 min
Aug 27, 5:27 PM CDTFlash Flood WarningLZKArkansas, Desha, Monroe, Prairie3 hr
Aug 27, 5:34 PM CDTTornado WarningMEGLee, Phillips11 min
Aug 27, 5:38 PM CDTTornado WarningMEGLee, Phillips37 min
Aug 27, 5:46 PM CDTTornado WarningMEGLee, Phillips, St. Francis29 min
Aug 27, 6:08 PM CDTTornado WarningLZKWhite, Woodruff52 min
Aug 27, 6:17 PM CDTTornado WarningMEGLee, Phillips8 min
Aug 27, 6:19 PM CDTFlash Flood WarningLZKConway, Faulkner, Lonoke, Monroe, Perry, Prairie and 3 more3 hr
Aug 27, 6:25 PM CDTTornado WarningMEGLee, St. Francis19 min
Aug 27, 6:44 PM CDTTornado WarningLZKJackson, Woodruff18 min
Aug 27, 6:46 PM CDTTornado WarningMEGCross, St. Francis17 min
Aug 27, 6:54 PM CDTTornado WarningLZKIndependence, Jackson, White, Woodruff8 min
Aug 27, 7:00 PM CDTFlash Flood WarningMEGCross, Lee, St. Francis3 hr
Aug 27, 7:00 PM CDTTornado WarningMEGLee, St. Francis30 min
Aug 27, 7:09 PM CDTTornado WarningMEGCross, Poinsett36 min
Aug 27, 7:14 PM CDTTornado WarningLZKIndependence, Jackson, White, Woodruff28 min
Aug 27, 7:21 PM CDTFlash Flood WarningLZKCleburne, Jackson, White, Woodruff3 hr
Aug 27, 7:22 PM CDTTornado WarningLZKIndependence, Jackson20 min
Aug 27, 7:52 PM CDTTornado WarningMEGCross, Poinsett38 min
Aug 27, 7:57 PM CDTTornado WarningMEGCraighead, Poinsett35 min
Aug 27, 7:58 PM CDTTornado WarningMEGLafayette, Panola, Tate32 min
Aug 27, 8:12 PM CDTTornado WarningMEGCraighead, Poinsett48 min
Aug 27, 8:27 PM CDTTornado WarningMEGDeSoto, Marshall, Panola, Tate33 min
Aug 27, 8:33 PM CDTTornado WarningLZKLawrence, Sharp17 min
Aug 27, 8:47 PM CDTTornado WarningMEGCraighead, Mississippi, Poinsett43 min
Aug 27, 8:52 PM CDTTornado WarningLZKLawrence, Randolph, Sharp21 min
Aug 27, 8:52 PM CDTTornado WarningMEGCraighead, Greene23 min
Aug 27, 8:53 PM CDTFlash Flood WarningMEGCrittenden3 hr
Aug 27, 9:10 PM CDTFlash Flood WarningMEGCraighead, Cross, Poinsett3 hr
Aug 27, 9:12 PM CDTTornado WarningMEGCraighead, Greene48 min
Aug 27, 9:18 PM CDTFlash Flood WarningLZKCleburne, Independence, Izard, Jackson, Lawrence, Sharp3 hr
Aug 27, 9:49 PM CDTTornado WarningMEGClay, Greene23 min
Aug 27, 10:29 PM CDTTornado WarningMEGClay, Mississippi31 min
Aug 27, 10:59 PM CDTTornado WarningMEGClay23 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

Little Rock, AR (KLZK), launched 12:00Z, 8.8 hours before the alert went out and 105 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.

Skew-T log-pSkew-T log-p diagram, Little Rock, AR at 12:00Z on 2020-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 305 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Little Rock, AR at 12:00Z on 2020-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
305 J/kg
Mixed-layer CIN
-139 J/kg
Mixed-layer LCL
1050 m above ground
0-6 km bulk shear
30 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
50 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

437 
WWUS20 KWNS 272044
SEL8  
SPC WW 272044
ARZ000-MSZ000-280200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 458
NWS Storm Prediction Center Norman OK
350 PM CDT Thu Aug 27 2020

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Central and eastern Arkansas
  Western and northern Mississippi

* Effective this Thursday afternoon and evening from 350 PM until
  900 PM CDT.

* Primary threats include...
  A couple tornadoes possible

SUMMARY...Brief tornadoes will remain possible within a broader
rainfall region to the east and northeast of tropical cyclone Laura.

The tornado watch area is approximately along and 50 statute miles
east and west of a line from 150 miles north northwest of Greenville
MS to 20 miles south of Greenwood MS. For a complete depiction of
the watch see the associated watch outline update (WOUS64 KWNS
WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 454...WW 455...WW
456...WW 457...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 0.5 inches. Extreme turbulence and surface wind
gusts to 50 knots. A few cumulonimbi with maximum tops to 350. Mean
storm motion vector 16050.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 27, 6:36 AM CDTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 14 more114 min
Aug 27, 7:47 AM CDTTornado WatchSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 19 more8 hr
Aug 27, 2:41 PM CDTMesoscale DiscussionSPCChicot, Crittenden, Cross, Desha, Lee, Phillips and 2 more94 min
Aug 27, 5:50 PM CDTMesoscale DiscussionSPCCleburne, Craighead, Crittenden, Cross, Faulkner, Independence and 10 more115 min
Aug 26, 9:03 PM CDTTornado WatchSPCAdams, Wilkinson11 hr
Aug 27, 11:10 AM CDTMesoscale DiscussionSPCCopiah, Jefferson Davis, Lawrence, Marion, Simpson, Walthall2 hr

Nearby

Tornado Watches in Arkansas, 2020Tornado Watches in Mississippi, 2020Every tornado watch in 2020

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.