Subj : DAY2SVR: Nws Storm Prediction Center Norman Ok To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Thu Sep 21 2023 06:02:19 ACUS02 KWNS 210602 SWODY2 SPC AC 210600 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 0100 AM CDT Thu Sep 21 2023 Valid 221200Z - 231200Z ....THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM CENTRAL/EASTERN NE INTO SOUTH-CENTRAL SD... ....SUMMARY... Severe thunderstorms will be possible across parts of the central and northern Plains, mainly Friday afternoon into Friday night. Hail, strong/damaging gusts, and a tornado or two will be possible. ....Parts of the central/northern Plains... A mid/upper-level cyclone initially near the northern Great Basin will begin moving eastward on Friday, with multiple smaller-scale vorticity maxima expected to move northeastward across parts of the northern Rockies and central/northern Plains in advance of this cyclone. As this occurs, a surface cyclone will gradually deepen across the central High Plains, with another surface cyclone potentially developing across southeast MT. An outflow-reinforced baroclinic zone is expected to move northward across parts of NE/SD, in the wake of morning convection. In general, the environment will become favorable for organized storms during the afternoon/evening across much of the central Plains into parts of SD, with steep midlevel lapse rates supporting moderate buoyancy, and sufficient deep-layer shear for supercells and organized clusters. The greatest storm coverage is expected from southern SD into northern NE, in advance of a midlevel shortwave trough ejecting eastward ahead of the primary mid/upper cyclone. Hail and localized severe gusts will be possible with the strongest cells/clusters in this region. In addition, some tornado threat could evolve in this area, depending on how far north the effective warm front can advance by late afternoon/early evening. Storm development farther south into south-central NE and northern KS is much more uncertain, with stronger ascent expected to be displaced to the north. However, a conditional risk for a supercell or two remains evident, especially in the vicinity of the effective warm front. Additionally, some increase in elevated storm coverage is possible from northeast KS into eastern NE/western IA late Friday night, in conjunction with a moderate low-level jet. ....Coastal NC... A deepening cyclone is expected to move northward in relatively close proximity to the NC coast Friday into Friday night, though the track and intensity of this system remains somewhat uncertain. There is some potential for the warm sector of this cyclone to spread across the Outer Banks and potentially farther west into eastern NC, which could result in the threat for a brief tornado or two, depending on the intensity of the cyclone and its attendant low-level flow. Probabilities may eventually be needed for some part of eastern NC, depending on the ultimate track/intensity of the system. ...Dean.. 09/21/2023 $$ = = = 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 3.14-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .