SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0759 PM CDT Tue Sep 19 2023 Valid 200100Z - 201200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF WEST AND NORTH TEXAS...INTO OKLAHOMA... ...SUMMARY... Thunderstorms, associated with large hail (possibly greater than two inches in diameter) and wind damage, will be likely from parts of west and north Texas, into Oklahoma this evening. ...West and North Texas/Oklahoma... Latest water vapor imagery shows evidence of a shortwave trough over the central High Plains. RAP analysis has several vorticity maxima, associated with the trough, located from western Oklahoma into western Kansas. At the surface, a 1003 mb low is analyzed over northwest Texas, with backed southeasterly flow over much of Oklahoma and south-central Kansas. A pocket of maximized low-level moisture is present in this area where surface dewpoints are generally in the 60s F. This is contributing to a north-to-south corridor of moderate instability, with the RAP estimating MLCAPE in the 1500 to 2500 J/kg range. Thunderstorms are ongoing near the instability axis from west-central Oklahoma south-southwestward into west-central Texas. Isolated storms are also located in south-central Kansas. MCS development will be likely this evening as the storms move east-southeastward across the southern Plains. In addition to moderate instability, shear profiles across much of the southern Plains appear favorable for severe storms. The 00Z sounding from Norman, Oklahoma has 0-6 km shear near 45 knots with strong directional shear from the surface to 700 mb. In addition, 700-500 mb lapse rates are near 8.5 C/km. This moderate deep-layer shear, combined with steep mid-level lapse rates, will support supercells with large hail this evening. Hailstones of greater than two inches in diameter will be possible with the most intense updrafts, mainly across southwest Oklahoma and northwest Texas. A wind-damage threat will also be likely with supercells, and with organized multicells. The severe threat is expected to continue through much of the evening. ..Broyles.. 09/20/2023
