SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1132 PM CST Sat Mar 11 2023 Valid 121200Z - 131200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF THE SOUTHEAST... ...SUMMARY... Scattered severe thunderstorms capable of producing large hail, damaging winds, and a couple tornadoes are possible Sunday across parts of the Southeast. A few strong/severe storms are also possible in the central valley region of California. ...Southeast... A few weak short-wave troughs will track east-southeast across the Gulf States Sunday as the southern stream is suppressed a bit in response to a strong digging short wave over the Great Lakes. In the absence of meaningful height falls, weak surface low will advance east across the lower MS Valley along the surging cold front into southwest AL by early evening. Downstream, a secondary surface low should evolve off the SC Coast during the latter half of the period, as mid-level flow increases over the southern Appalachians. Surface front and organized outflow boundaries should serve as the focus for potentially organized, strong/severe convection. Early this morning, an MCS has evolved over southern AR along/north of a warm front draped across this region. This activity may also be partially influenced by a weak short-wave trough that is currently ejecting across the mid-MS Valley. Much of the northern Gulf States remain cool/stable in the boundary layer with greater buoyancy observed across east TX into LA/western MS. This MCS will continue propagating southeast, likely expanding east into AL/northern GA by the start of the day1 period. As a result, instability required for robust convection should extend primarily across the southern Gulf States into southern GA. Strong westerly flow and a surging cold front will encourage much of the aforementioned convection to propagate toward northern FL. Current thinking is a mixed storm mode, likely dominated by line segments and multi-cell clusters, will spread across the Southeast by late afternoon. Even so, strong shear should aid a few supercells as abundant buoyancy will be in place prior to convection. Hail, damaging winds, along with a few tornadoes can be expected with this activity. ...Central Valley Region of CA... The next within a series of speed maxima will advance inland across southern CA after 18z. Lower 50s surface dew points are in place across the central CA valley region, and this moisture should hold through the day given the current flow regime. Given the cool mid-level temperatures, afternoon convection should once again develop within a favorably sheared environment for robust convection. Forecast soundings suggest supercells are possible and hail may approach severe levels with the strongest updrafts. Any convection that develops will weaken with loss of daytime heating. ..Darrow/Moore.. 03/12/2023
