Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Fri Aug 16 2024 17:31:01 ACUS02 KWNS 161730 SWODY2 SPC AC 161729 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1229 PM CDT Fri Aug 16 2024 Valid 171200Z - 181200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS IN PARTS OF KY/OH VALLEY AND THE PACIFIC NORTHWEST... ....SUMMARY... Scattered severe thunderstorms are possible in parts of Kentucky and the Ohio Valley on Saturday afternoon through about dusk. Damaging winds and hail are the primary threats. Isolated to scattered severe wind and hail are also possible across parts of western Oregon into southwest Washington on Saturday afternoon through about dusk. ....Lower Great Lakes to the Mid/Deep South... A slow-moving mid/upper trough should continue east across the Great Lakes through early Sunday. An occluded surface cyclone over Lower MI should drift into Lake Huron. A weak cold front will arc to the south-southwest over the Upper OH Valley and trail southwest to west across the Mid-South into OK. Along this baroclinic zone, ongoing convection at 12Z Saturday appears most probable over the Ozarks vicinity. It is plausible this activity may intensify as downstream diurnal destabilization occurs in the Mid to Deep South. Within the mid-level flow gradient, semi-organized clusters are possible with a threat for sporadic damaging winds. The belt of seasonably strong mid to upper-level westerlies should be centered across KY/TN within the basal portion of the Great Lakes trough. Consensus of guidance suggests 700-mb westerlies will be stronger relative to Friday, likely centered on the OH Valley region. With the more prominent diurnal destabilization occurring across KY into the OH Valley, away from the influence of Ozarks to Deep South earlier-day convection, this setup may yield a greater concentration of damaging winds and some severe hail along this portion of the front. Despite the predominately westerly flow regime, deep-layer speed shear should support a mix of multicell clusters and semi-discrete, transient supercell structures. Multiple convective rounds are possible during the afternoon into the early to mid evening. ....Pacific Northwest... A vigorous shortwave impulse, embedded within a broader mid/upper trough, should move inland across northern CA into western OR. This feature may take on a negative-tilt, with pronounced mid-level height falls favorably timed to peak diurnal heating. A strengthening mid to upper jetlet will overspread this region with mid-level winds backing to the south-southeast. Within the exit region of this meridional flow regime, scattered to numerous late-afternoon and evening thunderstorms should be focused from south to north across the Cascade Range. While buoyancy should remain weak, steep mid to low-level lapse rates should support a few supercells capable of both severe hail and wind. The wind threat may be relatively greater across parts of the Columbia Valley near the OR/WA border area as storms cluster into the early evening. ....Eastern Great Basin... A plume of richer 700-mb moisture will advect north from AZ, with peripheral flow enhancement from the West Coast shortwave trough. Guidance is fairly consistent that late morning to midday thunderstorm activity will increase as diurnal destabilization ensues. While this may not be favorably timed with peak heating, the steep lapse-rate environment and moderate deep-layer flow suggest a threat for strong to sporadic severe gusts and small hail. A later round of late afternoon to early evening thunderstorms may occur along the western periphery of this earlier day activity, with a similar threat for low-probability severe. ....Central and northern High Plains... Mid-level ridging is expected across this region between the Great Lakes and West Coast trough, but with moderate mid to upper-level westerlies. Very isolated thunderstorms are possible during the late afternoon to early evening along portions of a lee surface trough. These appear most probable along the northwest periphery of the central Great Plains to Ozarks buoyancy plume, in vicinity of northwest KS, and separately near the Canadian border as a minor shortwave impulse crests the ridge in the southern Prairie Provinces. Deep-layer shear will be adequate for a couple supercells capable of very isolated severe hail and wind. ...Grams.. 08/16/2024 $$ = = = To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .