SPC 0600Z Day 2 Outlook
Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1247 AM CDT Sat Oct 23 2021 Valid 241200Z - 251200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE MID MISSISSIPPI VALLEY AND OZARKS... ...SUMMARY... Scattered severe thunderstorms associated with damaging wind gusts, isolated large hail and some tornadoes will be likely from parts of the Ozarks into the mid Mississippi Valley. A more isolated severe threat is expected in parts off the Arklatex, western Tennessee Valley, lower Ohio Valley and southern to central Plains. ...Mid Mississippi Valley/Ozarks... An upper-level trough will move eastward across the southern and central Plains and become more amplified on Sunday. Ahead of the trough, southwest mid-level flow will be in place across the Ozarks and mid Mississippi Valley. At the surface, the western edge of a moist airmass will be located across the southern Plains extending north-northeastward into the eastern half of Kansas. During the day, a surface low will move eastward across northern Missouri with a warm front located in central Illinois and central Indiana. A cold front will extend southwestward across eastern Kansas and northeastern Oklahoma. Thunderstorms are expected to first develop to the north of the track of the surface low and along the warm front by late morning. Although much of this activity will be elevated, a hail threat should develop with the stronger cores. Further south, surface heating ahead of the cold front will result in the development of moderate instability by midday. This combined with increasing low-level convergence along the front will result in surface-based convective initiation from north-central Missouri southwestward into central and southwestern Missouri during the afternoon. As storm coverage expands during the mid to late afternoon, MCS development is expected. This organized line of severe storms will move east-southeastward and persist into the early overnight period. The models are in relatively good agreement concerning many aspects of this system. Moderate instability is forecast to develop across a fairly broad moist sector. MLCAPE is expected to peak in the 1500 to 2500 J/kg range from far eastern Oklahoma into north-central Missouri. 0-6 km shear is forecast to be in the 35 to 45 kt range along much of the instability axis. This environment should support supercell development with a potential for large hail and wind damage. The greatest threat for large hail should exist early in the event when instability will be greatest and cells will tend to be more discrete. The more dominant supercells should have a tornado threat. As cells congeal into a line during the late afternoon and early evening and as the low-level jet strengthens, embedded supercells within the line should continue to have a tornado threat. Eventually, a nearly continuous line of severe storms is expected with wind-damage becoming the greatest threat. Isolated wind gusts of greater than 65 knots will be possible with the more organized bowing segments. The line should continue across the lower Ohio and mid Mississippi Valleys during the late evening and early overnight period, where isolated damaging wind gusts will be possible. ...Pacific Northwest Coast... An upper-level trough will approach the coast of the Pacific Northwest on Sunday. Ahead of the system, strong large-scale ascent will overspread the Pacific Northwest. This combined with 500 mb temperatures near -24C will create steep mid-level lapse rates and weak instability. This may be enough for a marginal hail threat on Sunday afternoon and evening along the coast as cells move inland. ..Broyles.. 10/23/2021 Read more LIVE: spc.noaa.gov
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