


Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
259 ACUS48 KWNS 150858 SWOD48 SPC AC 150857 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0357 AM CDT Wed Oct 15 2025 Valid 181200Z - 231200Z ...DISCUSSION... ...Saturday/Day 4... A large-scale mid-level trough will move through the Great Plains on Saturday, with a moist airmass in place across the Ark-La-Tex, Ozarks and lower Mississippi Valley. Within this airmasss, an area of thunderstorms is likely to be ongoing at the start of the period across parts of eastern Oklahoma and southwest Missouri. Ahead of this convection, moisture advection and surface heating will contribute to a moderately unstable airmass by midday, with forecasts increasing MLCAPE to around 1500 J/kg across the Ark-La-Tex. Thunderstorm development appears likely in the early afternoon over much of Ozarks, where moderate deep-layer shear is forecast. The ECWMF is forecasting 0-6 km shear in the 40 to 50 knot range over this part of the moist sector, suggesting a severe threat will be probable during the afternoon. Wind damage will be possible with bowing line segments, and low-level shear should be sufficient for tornadoes. Hail will also be possible, mainly if supercells can develop. Storm mode still remains uncertain. If the mode goes linear early in the event, the wind-damage threat could become dominant. The severe threat should persist through the evening and into the overnight period, as an MCS moves through the central Gulf Coast states. ...Sunday/Day 5 and Monday/Day 6... The mid-level trough is forecast to move through the Ohio and Tennessee Valleys on Sunday, and to the Atlantic Seaboard on Monday. Ahead of the trough, scattered thunderstorms with an isolated severe threat will be possible Sunday and Sunday night, with much of the convection moving offshore into the Atlantic relatively early on Monday. An isolated severe threat would still be possible closer to the mid-level low in parts of the Mid-Atlantic Monday afternoon. ...Tuesday/Day 7 and Wednesday/Day 8... From Tuesday into Wednesday, a mid-level low is forecast to move across the southwestern U.S., reaching the southern Rockies by Wednesday night. If the models are relatively close on the system timing, an isolated severe threat could develop ahead of the system Wednesday night across the southern Plains. However, uncertainty at this range is substantial. ..Broyles.. 10/15/2025