Alert archive / Arkansas / Mesoscale Discussions in 2012
Mesoscale Discussion 1728
The Storm Prediction Center issued this mesoscale discussion at Aug 9, 2012, 4:44 PM CDT for 12 counties in Arkansas; Bryan County, Choctaw County, McCurtain County, Oklahoma; 5 counties in Texas. It was in force for 61 min.
The area
The outline as issued.
The facts
- Issued
- Aug 9, 2012, 4:44 PM CDT (21:44 UTC)
- Expired
- Aug 9, 2012, 5:45 PM CDT
- In force
- 61 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
Counties Clark County, AR, Garland County, AR, Hot Spring County, AR, Howard County, AR, Little River County, AR, Lonoke County, AR, Montgomery County, AR, Pike County, AR, Polk County, AR, Pulaski County, AR, Saline County, AR, Sevier County, AR, Bryan County, OK, Choctaw County, OK, McCurtain County, OK, Delta County, TX, Fannin County, TX, Grayson County, TX, Lamar County, TX, Red River County, TX
The radar
The Western Arkansas radar (KSRX), 143 km from the middle of the area, began a volume at 21:47 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.
The nearest sounding before it
Shreveport, LA (KBAD), launched 12:00Z, 9.7 hours before the alert went out and 193 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
- 1139 J/kg
- Mixed-layer CIN
- -99 J/kg
- Mixed-layer LCL
- 1169 m above ground
- 0-6 km bulk shear
- 15 kt
- 0-1 km storm-relative helicity
- 77 m²/s²
- 0-3 km storm-relative helicity
- 56 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.9
The text
As transmitted, in the capitals the NWS used until 2016.
029
ACUS11 KWNS 092145
SWOMCD
SPC MCD 092144
ARZ000-TXZ000-OKZ000-092245-
MESOSCALE DISCUSSION 1728
NWS STORM PREDICTION CENTER NORMAN OK
0444 PM CDT THU AUG 09 2012
AREAS AFFECTED...SERN OK...SWRN AR
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 092144Z - 092245Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...DMGG WINDS WILL BE POSSIBLE THROUGH THE EVENING AS STORMS
GRADUALLY INCREASE IN COVERAGE ACROSS THE MCD AREA.
DISCUSSION...INCREASINGLY AGITATED CU FIELD IS BEGINNING TO BECOME
MORE WELL-DEFINED ALONG A WEAK SURFACE TROUGH AND CONFLUENT SURFACE
WINDS EXTENDING FROM SRN IL SWWD INTO W CNTRL AR AND ALONG THE OK/TX
BORDER. MODIFYING THE UPSTREAM 18Z LAMONT SOUNDING FOR AMBIENT
SURFACE CONDITIONS...MLCAPE NEAR 750-1000 J/KG AND MODEST NLY FLOW
ALOFT SHOULD BE SUFFICIENT FOR A FEW SEMI-ORGANIZED MULTICELLS
CAPABLE OF DMGG WINDS...GIVEN A DEEPLY MIXED BOUNDARY LAYER AND
EVAPORATIVE ENHANCEMENTS TO ANY DOWNBURSTS THAT OCCUR.
ATTM...CONVECTIVE COVERAGE IS THE PRIMARY UNCERTAINTY REGARDING A WW
ISSUANCE. ALTHOUGH DARKENING ON WV IMAGERY IN THIS REGION IS PERHAPS
ALLUDING TO A WEAK VORT MAX...GENERALLY WEAK UPPER FORCING SHOULD
LIMIT A MORE WIDESPREAD THREAT FROM DEVELOPING.
..HURLBUT/CORFIDI.. 08/09/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LZK...SHV...TSA...FWD...OUN...
LAT...LON 33229621 33519728 34019678 34389495 34859309 35109211
34689183 34049308 33309533 33229621Nearby
Mesoscale Discussions in Arkansas, 2012Mesoscale Discussions in Texas, 2012Mesoscale Discussions in Oklahoma, 2012Every mesoscale discussion in 2012
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.