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 

   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. 

   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. 

   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. 

   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 www.spc.noaa.gov for graphic product...

   ATTN...WFO...TSA...FWD...OUN...DDC...SJT...

   LAT...LON   32859904 33389902 33969939 34799995 35859994 36569990
               37049934 36649736 34919603 33709636 33149736 32859904