Mesoscale Discussion 2138
Issued: · Valid: –
Summary
Isolated severe storms capable of producing damaging wind gusts up to 65 mph and hail are expected to increase across portions of northern and central Arkansas and the ArkLaTex region this afternoon. The threat is expected to intensify between 7:00 PM and 8:00 PM CDT.
Product Text
000 ACUS11 KWNS 261818 SWOMCD SPC MCD 261818 ARZ000-TXZ000-OKZ000-262015- Mesoscale Discussion 2138 NWS Storm Prediction Center Norman OK 0118 PM CDT Wed Aug 26 2026 Areas affected...portions of northern and central Arkansas into the ArkLaTex Concerning...Severe potential...Watch possible Valid 261818Z - 262015Z Probability of Watch Issuance...40 percent SUMMARY...The threat for at least isolated severe storms capable of damaging winds with gusts of 60-65 mph and hail is expected to increase by 20-21Z. Convective trends are being monitored for a possible severe thunderstorm watch. DISCUSSION...Early afternoon visible satellite shows a growing cumulus field and isolated thunderstorm development from south-central MO through northwest AR into northeast OK along a weak surface front in the area. Ahead of the front, temperatures have warmed into the mid to upper 90s, which, combined with boundary-layer dewpoints in the upper 60s to mid 70s, is yielding MLCAPE of 2000-3000 J/kg with a weakening cap. In the absence of appreciable forcing for ascent, continued heating and convergence along the front are expected to foster a gradual increase in storms and related severe weather risk over the next 1-2 hours amidst a weakly sheared environment (i.e., bulk shear magnitudes of generally less than 30 kt), per regional VWPs. As such, the severe threat should remain somewhat isolated at least initially with the primary hazards being locally damaging winds with gusts of 60-65 mph and marginally severe hail. Time-lagged HRRR and RRFS ensemble guidance has shown a consistent signal for storm clustering to occur by late afternoon into early evening, at which point the damaging wind threat could increase in areal extent. A separate area of severe storms may materialize later this afternoon over the ArkLaTex, ahead of a surface low and multiple MCVs approaching the region from the west/northwest. Here, too the environment is expected to become supportive of some wind and hail risk. ..Mead/Mosier.. 08/26/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LZK...SHV...TSA... LAT...LON 35239468 35689428 35959345 35669268 35249220 34379215 33419254 33119322 33179410 33739482 35239468 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN