SPC 1300Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0749 AM CDT Wed May 14 2025 Valid 141300Z - 151200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PORTIONS OF THE CENTRAL AND NORTHERN PLAINS... ...SUMMARY... Scattered strong to severe thunderstorms are possible mainly over parts of the Dakotas and Nebraska this afternoon and evening, and far western Iowa and southwest Minnesota overnight. A few strong to severe storms may occur from parts of the southern Appalachians to the Carolinas and Mid-Atlantic this afternoon. ...Northern/Central Plains... Surface low pressure will deepen in the vicinity of the CO/KS/NE border today in response to the approach of an upper-level trough, as an associated surface cold front moves slowly east across the central/northern Plains. Low-level moisture advection and steep mid-level lapse rates (in excess of 8 deg C/km) will result in MLCAPE of 2500-3000 J/kg across central NE, with weaker instability northward across the central Dakotas. Thunderstorm development is expected by late afternoon near the front across the Dakotas and central/northern NE, with severe hail and wind the primary risks. Damaging winds will become more likely as one or two clusters ultimately evolve over central/northern NE and move towards southeast SD/southwest MN and far northwest IA during the late evening and overnight. Across southwest/central NE, more discrete supercell structures will be possible with storms developing closer to the surface low/dryline intersection, with large to very large hail possible. A 5 percent tornado probability has been introduced across portions of central NE, where a short-duration window may exist for a couple of tornadoes this evening with any semi-discrete storm or small cluster in the presence of increasing low-level shear. Expected upscale growth should limit the time frame for supercell tornado potential. ...Southern Appalachians into the Carolinas and Mid-Atlantic... Weak to moderate instability will develop from the southern Appalachians to the Carolinas Wednesday. As a mid-level shortwave trough overspreads the region, scattered thunderstorms are expected to develop. Sufficient shear of 25 to 30 knots will support some storm organization including potential for transient supercell structures. Modestly steep mid-level lapse rates should support the potential for large hail and perhaps isolated damaging wind gusts. ..Bunting/Dean.. 05/14/2025