Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
777 ACUS02 KWNS 191724 SWODY2 SPC AC 191723 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1123 AM CST Wed Nov 19 2025 Valid 201200Z - 211200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF THE SOUTHERN PLAINS... ...SUMMARY... Isolated severe thunderstorms are possible across the southern Plains tomorrow (Thursday). An instance or two of severe wind, hail, or a brief tornado may occur. ...Synopsis... The upper-air pattern across much of the western and central U.S. tomorrow (Thursday) will be characterized by broad mid-level troughing, with multiple embedded shortwave troughs rotating around the broader scale cyclonic flow aloft. One upper trough will pivot southeastward along the CA coastline with cooler temperatures aloft, supporting isolated lightning flashes. A second mid-level shortwave trough will eject into the Plains during the day, encouraging a continued northward flux of rich low-level moisture amid a warm-air advection regime. Strong forcing for ascent will promote an increase in coverage of thunderstorms through the period across the southern Plains as the mid-level trough overspreads the region. Despite expected meager instability, strong vertical wind shear will accompany the mid-level trough, which may support isolated strong to potentially severe storms. ...Southern Plains... The aforementioned broad upper troughing will support a relatively prolonged low-level warm-air/moisture advection regime, where low-level confluence will support widespread showers and at least scattered thunderstorms at the start of the period (12Z Thursday), from central TX to central OK. Given expected widespread cloudiness and mediocre mid-level lapse rates, buoyancy should be quite weak initially. However, with daytime heating, some boundary-layer mixing (albeit modest), should help boost MLCAPE to several hundred J/kg. While deep-layer vertical flow/shear should remain largely unidirectional, some of the latest guidance suggests that slightly stronger flow aloft will overspread the warm sector compared to earlier guidance members. As such, considerable size/elongation of the hodographs will result in 40-50 kts of effective bulk shear, with some backing of the low-level winds possible closer to the surface low in northern TX into OK. While this shear profile would support severe potential, the presence of widespread clouds, training thunderstorms, and poor tropospheric lapse rates (and resultant buoyancy) should limit severe potential. The current thinking is that a few stronger thunderstorms will form within a confluence axis just ahead of the aforementioned training thunderstorms in central OK to central TX by mid to late afternoon. Given favorable vertical wind shear, multicells and supercells will be possible initially, before unidirectional flow encourages the development of a loosely organized line of storms. Discrete storms will have the best potential for producing an instance or two of marginally severe wind or hail. A brief tornado is also possible with the storms that are closer to the surface low over northern TX to central/eastern OK. Since most of the available buoyancy will likely be driven by boundary-layer heating, the severe threat is expected to wane after dark. ..Squitieri.. 11/19/2025 $$