Alert archive / Arkansas / Mesoscale Discussions in 2011
Mesoscale Discussion 538
The Storm Prediction Center issued this mesoscale discussion at Apr 23, 2011, 5:02 PM CDT for 27 counties in Arkansas; 10 counties in Oklahoma. It was in force for 58 min.
The area
The outline as issued.
The facts
- Issued
- Apr 23, 2011, 5:02 PM CDT (22:02 UTC)
- Expired
- Apr 23, 2011, 6:00 PM CDT
- In force
- 58 min
- Issued by
- the Storm Prediction Center
All 37 counties
Baxter County, AR, Clay County, AR, Cleburne County, AR, Conway County, AR, Craighead County, AR, Crawford County, AR, Franklin County, AR, Greene County, AR, Independence County, AR, Izard County, AR, Johnson County, AR, Lawrence County, AR, Logan County, AR, Madison County, AR, Marion County, AR, Newton County, AR, Polk County, AR, Pope County, AR, Randolph County, AR, Scott County, AR, Searcy County, AR, Sebastian County, AR, Sharp County, AR, Stone County, AR, Van Buren County, AR, Washington County, AR, Yell County, AR, Adair County, OK, Atoka County, OK, Choctaw County, OK, Haskell County, OK, Latimer County, OK, LeFlore County, OK, McCurtain County, OK, Pittsburg County, OK, Pushmataha County, OK, Sequoyah County, OK
The radar
The Western Arkansas radar (KSRX), 94 km from the middle of the area, began a volume at 22:05 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, 10.0 hours before the alert went out and 172 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
- 1105 m above ground
- 0-6 km bulk shear
- 55 kt
- 0-1 km storm-relative helicity
- 185 m²/s²
- 0-3 km storm-relative helicity
- 514 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.1
The text
As transmitted, in the capitals the NWS used until 2016.
287
ACUS11 KWNS 232202
SWOMCD
SPC MCD 232202
ARZ000-MOZ000-OKZ000-TXZ000-232300-
MESOSCALE DISCUSSION 0538
NWS STORM PREDICTION CENTER NORMAN OK
0502 PM CDT SAT APR 23 2011
AREAS AFFECTED...NRN AR...SERN OK
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY
VALID 232202Z - 232300Z
INCREASING THUNDERSTORM COVERAGE IS ANTICIPATED OVER THE NEXT FEW
HRS ACROSS PORTIONS OF SERN OK AND NRN AR...ALTHOUGH STILL SOMEWHAT
UNCERTAIN DUE TO THE PRESENCE OF AMPLE CLOUD COVER. SHOULD
CONVECTION BECOME ROOTED IN THE BOUNDARY LAYER...A THREAT OF DMGG
WINDS...LARGE HAIL...AND PERHAPS ISOLATED TORNADOES WILL LIKELY
DEVELOP. A TORNADO WATCH WILL LIKELY BE CONSIDERED SOON...AND PARTS
OF SERN OK CURRENTLY INCLUDED WITHIN SVR WW 187 MAY NEED TO BE
UPGRADED TO A TORNADO WATCH.
RECENT SATELLITE TRENDS INDICATE SOME ENHANCEMENT IN CONVECTION
ACROSS ERN OK INTO NWRN AR ACROSS A STALLED FRONT...AIDED BY WEAK
CONVERGENCE ALONG THE FRONT WITH LOW-LEVEL ISENTROPIC ASCENT FOCUSED
N OF THE FRONT. ADDITIONALLY...WEAK DEEP-LAYER ASCENT APPEARS TO BE
OVERSPREADING THE REGION FROM THE SRN PLAINS /PER WATER VAPOR
IMAGERY/. DESPITE PERSISTENT CLOUD COVER ACROSS THE WARM
SECTOR...TEMPERATURES HAVE HEATED INTO THE MID-UPPER 70S. AMPLE
LOW-LEVEL MOISTURE COMBINED WITH THE PRESENCE OF AN EML OVERHEAD HAS
YIELDED MLCAPE VALUES RANGING BETWEEN 1500-2500 J/KG...WITH LITTLE
TO NO CINH. SHORT TERM HI-RES MODEL GUIDANCE INDICATES AN UPSWING IN
SFC-BASED CONVECTION THROUGH 00Z. KINEMATIC FIELDS WILL BE FAVORABLE
FOR SUPERCELLS...GIVEN EFFECTIVE BULK SHEAR 40-50 KTS.
ADDITIONALLY...THE POTENTIAL FOR TORNADOES MAY ALSO
EXIST...PARTICULARLY ALONG THE STALLED FRONT WHERE 0-1 KM SRH
HELICITY IS MAXIMIZED /200-250 M^2 S^-2/.
..ROGERS.. 04/23/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MEG...LZK...SHV...TSA...FWD...OUN...
LAT...LON 35959002 35559153 35209292 34269410 34009450 33859535
34129605 34419631 35089567 35749493 36119432 36189354
36309309 36309251 36359157 36449033 35959002SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 22, 7:29 PM CDT | Mesoscale Discussion | SPC | Baxter, Boone, Clay, Fulton, Greene, Izard and 7 more | 91 min |
| Apr 22, 8:09 PM CDT | Mesoscale Discussion | SPC | Benton, Carroll, Crawford, Madison, Washington | 96 min |
| Apr 22, 9:39 PM CDT | Mesoscale Discussion | SPC | Carroll, Crawford, Franklin, Madison, Sebastian, Washington | 66 min |
| Apr 22, 11:04 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Benton, Boone, Carroll, Madison, Marion and 3 more | 7 hr |
| Apr 22, 11:10 PM CDT | Mesoscale Discussion | SPC | Baxter, Benton, Boone, Carroll, Crawford, Franklin and 4 more | 2 hr |
| Apr 23, 2:33 AM CDT | Mesoscale Discussion | SPC | Benton, Boone, Carroll, Madison, Marion, Washington | 87 min |
| Apr 23, 5:06 AM CDT | Mesoscale Discussion | SPC | Benton, Boone, Carroll, Madison, Marion, Newton and 1 more | 24 min |
| Apr 23, 1:04 PM CDT | Mesoscale Discussion | SPC | Clay, Craighead, Mississippi | 86 min |
| Apr 23, 5:09 PM CDT | Mesoscale Discussion | SPC | Baxter, Clay, Fulton, Randolph | 2 hr |
| Apr 23, 5:38 PM CDT | Severe Thunderstorm Watch | SPC | Baxter, Benton, Boone, Carroll, Clay, Cleburne and 30 more | 6 hr |
| Apr 22, 11:35 PM CDT | Severe Thunderstorm Watch | SPC | Atoka, Carter, Cleveland, Coal, Comanche, Cotton and 19 more | 4 hr |
| Apr 23, 2:08 AM CDT | Mesoscale Discussion | SPC | Latimer, LeFlore, Pittsburg, Pushmataha | 67 min |
| Apr 23, 12:56 PM CDT | Mesoscale Discussion | SPC | Bryan, Carter, Choctaw, Jefferson, Johnston, Love and 2 more | 64 min |
| Apr 23, 3:05 PM CDT | Severe Thunderstorm Watch | SPC | Atoka, Bryan, Carter, Choctaw, Coal, Cotton and 11 more | 9 hr |
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.