Alert archive / Arkansas / Mesoscale Discussions in 2011
Mesoscale Discussion 845
The Storm Prediction Center issued this mesoscale discussion at May 21, 2011, 8:31 PM CDT for 51 counties in Arkansas; LeFlore County, Oklahoma. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- May 21, 2011, 8:31 PM CDT (01:31 UTC)
- Expired
- May 21, 2011, 10:00 PM CDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
All 52 counties
Arkansas County, AR, Ashley County, AR, Bradley County, AR, Calhoun County, AR, Clark County, AR, Cleburne County, AR, Cleveland County, AR, Columbia 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, Hempstead County, AR, Hot Spring County, AR, Howard County, AR, Independence County, AR, Jackson County, AR, Jefferson County, AR, Johnson County, AR, Lafayette County, AR, Lee County, AR, Lincoln County, AR, Logan County, AR, Lonoke County, AR, Monroe County, AR, Montgomery County, AR, Nevada 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, Searcy County, AR, Sebastian County, AR, Sevier County, AR, Stone County, AR, Union County, AR, Van Buren County, AR, White County, AR, Woodruff County, AR, Yell County, AR, LeFlore County, OK
The radar
The Little Rock radar (KLZK), 70 km from the middle of the area, began a volume at 01:32 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
Shreveport, LA (KSHV), launched 00:00Z, 1.5 hours before the alert went out and 226 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
- 2383 J/kg
- Mixed-layer CIN
- -12 J/kg
- Mixed-layer LCL
- 1022 m above ground
- 0-6 km bulk shear
- 44 kt
- 0-1 km storm-relative helicity
- 168 m²/s²
- 0-3 km storm-relative helicity
- 324 m²/s²
- Significant tornado parameter
- 3.7
- Supercell composite
- 31.0
The text
As transmitted, in the capitals the NWS used until 2016.
798
ACUS11 KWNS 220132
SWOMCD
SPC MCD 220131
ARZ000-LAZ000-OKZ000-220300-
MESOSCALE DISCUSSION 0845
NWS STORM PREDICTION CENTER NORMAN OK
0831 PM CDT SAT MAY 21 2011
AREAS AFFECTED...AR AND VICINITY
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 220131Z - 220300Z
STORMS SHOULD CONTINUE TO INCREASE IN COVERAGE ACROSS SRN AR...AND
SPREAD NEWD WITH TIME. WITH ENVIRONMENT SUPPORTIVE OF
SUPERCELLS/SEVERE POTENTIAL...WW ISSUANCE MAY BECOME NECESSARY.
STORMS CONTINUE TO SLOWLY INCREASE IN COVERAGE AND INTENSITY ACROSS
SRN AR...ON THE NWRN ARC OF AN OUTFLOW BOUNDARY EXTENDING FROM SRN
AR SEWD ACROSS NRN LA. STORMS APPEAR TO BE INITIATING IN A ZONE OF
WARM ADVECTION NEAR THE BOUNDARY...AND AS LOW-LEVEL JET INCREASES
THIS EVENING...STORM COVERAGE SHOULD CONTINUE TO INCREASE.
WITH THE BACKGROUND ENVIRONMENT FAVORABLE FOR SUPERCELLS...LARGE
HAIL AND ISOLATED DAMAGING WINDS WILL BE POSSIBLE WITH STRONGER
CELLS...AS STORMS SPREAD EWD/NEWD ACROSS AR THIS EVENING. THIS
REGION WILL CONTINUE TO BE MONITORED FOR POSSIBLE WW.
..GOSS.. 05/22/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MEG...JAN...LZK...SHV...TSA...
LAT...LON 32779204 33189362 33909436 34999473 35629427 35979247
35849134 34779061 33379151 32779204SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 22, 5:18 AM CDT | Mesoscale Discussion | SPC | Arkansas, Calhoun, Clark, Cleburne, Cleveland, Conway and 32 more | 57 min |
| May 22, 7:03 AM CDT | Severe Thunderstorm Watch | SPC | Arkansas, Bradley, Calhoun, Clark, Cleveland, Conway and 30 more | 7 hr |
| May 22, 11:15 AM CDT | Mesoscale Discussion | SPC | Arkansas, Bradley, Calhoun, Clark, Cleveland, Conway and 26 more | 90 min |
| May 22, 1:06 PM CDT | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Fulton, Marion | 114 min |
| May 22, 1:09 PM CDT | Mesoscale Discussion | SPC | Arkansas, Crittenden, Cross, Grant, Jefferson, Lee and 7 more | 66 min |
| May 22, 1:27 PM CDT | Tornado Watch | SPC | Benton, Carroll, Crawford, Franklin, Madison, Sebastian and 1 more | 8 hr |
| May 22, 3:10 PM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Cleburne, Independence, Izard, Jackson and 9 more | 65 min |
| May 22, 3:24 PM CDT | Tornado Watch | SPC | Baxter, Boone, Clay, Cleburne, Conway, Craighead and 22 more | 6 hr |
| May 22, 3:48 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Crawford, Franklin, Madison, Washington | 117 min |
| May 22, 5:21 PM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Carroll, Clay, Cleburne, Conway and 22 more | 54 min |
| May 22, 6:10 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Crawford, Franklin, Madison, Washington | 65 min |
| May 21, 7:08 PM CDT | Tornado Watch | SPC | Atoka, Bryan, Carter, Choctaw, Coal, Creek and 14 more | 3 hr |
| May 22, 12:42 PM CDT | Mesoscale Discussion | SPC | Carter, Garvin, Jefferson, Johnston, Love, Marshall and 2 more | 2 hr |
| May 22, 1:47 PM CDT | Tornado Watch | SPC | Atoka, Bryan, Carter, Coal, Garvin, Hughes and 10 more | 7 hr |
| May 22, 3:47 PM CDT | Mesoscale Discussion | SPC | Carter, Coal, Hughes, Johnston, Love, McIntosh and 5 more | 58 min |
| May 22, 6:34 PM CDT | Mesoscale Discussion | SPC | Atoka, Bryan, Carter, Coal, Garvin, Hughes and 10 more | 56 min |
Nearby
Mesoscale Discussions in Arkansas, 2011Mesoscale Discussions in Oklahoma, 2011Every mesoscale discussion in 2011
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.