SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0800 PM CDT Tue May 16 2023 Valid 170100Z - 171200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE CAROLINAS INTO SOUTHERN VIRGINIA... ...SUMMARY... A severe threat will continue this evening across parts of the southern and central Appalachians, eastward into the Piedmont. Wind damage and hail will be the primary threats. ...Southern and Central Appalachians/Piedmont... A series of minor shortwave troughs are currently moving eastward through the eastern U.S. this evening. At the surface, a moist airmass is located across much of the Southeast extending northeastward into parts of the southern and central Appalachians. Across the moist sector, surface dewpoints are generally in the 65 to 70 F range, which is contributing to moderate instability. Scattered thunderstorms are ongoing along the northern edge of the unstable airmass from the Tennessee Valley eastward into the Piedmont. A severe threat will likely continue for several more hours. At mid-levels, the latest RAP analysis shows a 50 to 60 knot jet max located across Virginia. This feature is contributing to moderate to strong deep-layer shear, which is evident on the Blacksburg and Richmond, Virginia WSR-88D VWPs. Forecast soundings this evening across south-central Virginia and north-central North Carolina generally have 0-6 km shear in the 50 to 60 knot range, with strong speed shear in the mid-levels. This profile will be favorable for isolated supercells with large hail and wind damage. However, the more favored storm mode will continue to be linear this evening. Wind damage will be possible along the leading edge of the faster moving bowing line segments. The severe threat is expected to continue into the mid to late evening, becoming more isolated with time. Further southwest across the Southeast, scattered thunderstorms are ongoing in a moist airmass. Although deep-layer shear is generally below 40 knots in most areas, low-level lapse are steep. This could be enough for a marginal wind-damage threat with the stronger multicells for another hour or two this evening. ...Central High Plains... A shortwave trough is evident on water vapor imagery across the central High Plains. The RAP is analyzing a pronounced vorticity max over western Nebraska. A small pocket of scattered thunderstorms are ongoing near the intersection of Colorado, Nebraska and Kansas. This activity is located along narrow corridor of moderate instability, where the RAP has MLCAPE estimated in the 1000 to 2000 J/kg range. In addition, the instability axis is located along the eastern edge of an elevated mixed layer, where 700-500 mb lapse are as great as 8.0 C/km. This, combined with moderate deep-layer, will be enough to continue an isolated severe threat with rotating cells. Hail and strong wind gusts will be the primary threats for another hour or two this evening. ..Broyles.. 05/17/2023
