Subj : MESO: Mesoscale Discussion 0764 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu May 11 2023 19:23:20 ACUS11 KWNS 111923 SWOMCD SPC MCD 111922=20 OKZ000-TXZ000-KSZ000-112115- Mesoscale Discussion 0764 NWS Storm Prediction Center Norman OK 0222 PM CDT Thu May 11 2023 Areas affected...Western and central Oklahoma and northwest Texas Concerning...Severe potential...Tornado Watch likely=20 Valid 111922Z - 112115Z Probability of Watch Issuance...95 percent SUMMARY...Increasing severe thunderstorm threat by late afternoon. A tornado watch is likely be 21Z. DISCUSSION...Morning convection along the Red River stunted destabilization during the morning as an expansive cloud shield overspread much of western Oklahoma. This cluster of storms eventually dissipated within the last hour in south-central Oklahoma and left a remnant outflow boundary across northwest Texas into south-central Oklahoma. Eastward advection of mid-level dry air has quickly eroded the mid-upper level cloud shield early this afternoon across western Oklahoma and rapid destabilization has begun, even north of the outflow boundary. Therefore, with continued heating, expect this outflow boundary to start lifting north this afternoon and eventually wash out across southwest Oklahoma. Dewpoints are now into the mid 60s as far north as I-40 in western Oklahoma with upper 60s to near 70 dewpoints along the Red River. This low-level moisture advection, coupled with heating across southwest Oklahoma will lead to a very unstable atmosphere with MLCAPE around 3000 J/kg by late afternoon.=20 Latest guidance (HRRR/RRFS/WoFs) is fairly consistent with storm development around 20Z to 21Z between I-40 and the Red River in western Oklahoma. This also correlates well with the region of enhanced cumulus developing along the dryline west of Childress.=20 Specific threats remain nebulous due to substantial uncertainties which still remain. Weak winds aloft (20-25 knots above 6 km per area VWP, forecast soundings, and the 12Z AMA RAOB) will result in poor hydrometeor venting and could limit the longevity of individual mesocyclones and a greater severe hail threat within the HP storm mode. However, stronger mid-level flow (sampled on the 12Z AMA RAOB) should overspread the dryline and provide sufficient shear for supercells. In addition, there is considerable variance with the strength of the low-level jet somewhere between 25 to 40 knots from 12Z guidance which will significantly modulate the tornado threat (specifically the strong tornado threat). A 21Z RAOB is planned from OUN which should help provide valuable data to both the thermodynamic profile in the wake of the morning convection, and the strength of the low-level jet.=20 Expect a primary threat for large hail and relatively brief tornadoes with a more conditional threat for strong, longer-lived tornadoes, particularly across south/central Oklahoma between I-40 and the Red River, if storm mode can remain favorable and if a stronger (30+ knot) low-level jet materializes. A tornado watch is likely be 21Z to cover this threat. ...Bentley/Guyer.. 05/11/2023 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!9u-HNbZN15Eaib7tfTX3ETsawoHVB61ifrJ6YIp1HMKjMCeUErK2m4PF3Ocmx75WkhKfvcKsE= 2GcyW0MYCkq-xfrREs$ for graphic product... ATTN...WFO...TSA...FWD...OUN...DDC...SJT... LAT...LON 32859904 33389902 33969939 34799995 35859994 36569990 37049934 36649736 34919603 33709636 33149736 32859904=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .