####018003540#### ACUS01 KWNS 180102 SWODY1 SPC AC 180100 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Wed Apr 17 2024 Valid 180100Z - 181200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE UPPER OHIO VALLEY AND FROM NORTHEAST KANSAS INTO WESTERN MISSOURI... ...SUMMARY... Thunderstorms capable of large hail and wind damage will be possible over the next couple of hours in the upper Ohio Valley. Marginally severe storms will be possible this evening in parts of the central Appalachians and Rio Grande Valley. Very large hail may occur late this evening into the overnight period across parts of the central Plains and Ozarks. ...Upper Ohio Valley/Central Appalachians... A line of strong to severe storms, arching from western Pennsylvania into southern Ohio, will continue to move eastward this evening into the higher terrain of the central Appalachians. The storms are located along an axis of instability, where the RAP has MLCAPE in the 500 to 1000 J/kg range. In addition to the instability, a vorticity max over eastern Ohio is supporting convective development along the line. The HRRR suggests that the line will continue to hold together for a few more hours as it moves into the central Appalachians. RAP forecast soundings ahead of the line from southeast of Pittsburgh, PA to Charleston, WV have 0-6 km shear near 40 knots, with 0-3 km lapse rates near 7.5 C/km. This environment should continue to support a wind-damage threat with the stronger cells embedded in the line. Isolated large hail could also accompany the stronger cells that rotate. The severe threat should become increasingly marginal as the evening progresses. ...Central Plains/Ozarks... An upper-level trough, and an associated 60 to 80 knot mid-level jet, will move through the central and northern Plains tonight. In response, a 40 to 50 knot low-level jet will strengthen across Kansas this evening. Elevated thunderstorms are expected to develop along the northern edge of the low-level jet this evening in southern Nebraska. Additional storms are expected to initiate in southeast Kansas. This activity will spread northeastward into northeast Kansas by late evening, where a warm front will be in place from west-northwest to east-southeast. RAP forecast soundings near and just south of the front by 06Z have MUCAPE near 2000 J/kg, with effective shear near 40 knots. Also, 700-500 mb lapse rates are forecast to be near 7.5 C/km. This will be favorable environment for supercells with large hail. The strongest of storms could produce hailstones greater than 2 inches in diameter. The storms are expected to move into northwest Missouri and far southeast Nebraska around or just after midnight. ...Rio Grande Valley... At the surface, a trough is located across west-central Texas extending southward into the Rio Grande Valley. Near the surface trough, widely scattered thunderstorms have developed along and near an axis of moderate instability. The RAP has MLCAPE along the instability axis in the 1500 to 2500 J/kg range. In addition, the RAP has 700-500 mb lapse rates near 7.5 C/km range, with 0-6 km shear generally in the 50 to 60 knot range. This will continue to support isolated supercell development for a few more hours this evening. Isolated large hail and marginally severe wind gusts will be the primary threats. ..Broyles.. 04/18/2024 $$