BBS: TELESC.NET.BR Assunto: DAY2SVR: Nws Storm Prediction Center Norman Ok De: COD Weather Processor Data: Mon, 27 Apr 2026 05:33:08 +0000 ----------------------------------------------------------- ACUS02 KWNS 270533 SWODY2 SPC AC 270531 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1231 AM CDT Mon Apr 27 2026 Valid 281200Z - 291200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS TUESDAY AFTERNOON AND EVENING IN A CORRIDOR ACROSS THE SOUTHEASTERN GREAT PLAINS THROUGH LOWER MISSISSIPPI AND TENNESSEE VALLEYS... ...SUMMARY... Scattered strong to severe thunderstorm development is probable across parts of the southeastern Great Plains through the lower Mississippi and Tennessee Valleys Tuesday afternoon and evening. The evolution of a long-lived organized cluster accompanied by potentially damaging wind gusts appears possible. ...Discussion... Latest model output still indicates that the center of a fairly broad surface cyclone may undergo further deepening while migrating northeast of the upper Great Lakes region during this period, particularly as it reaches the southeastern Hudson Bay vicinity, near the southeastern periphery of an evolving mid-level low. Surrounding this low, it appears that larger-scale mid-level troughing, encompassing much of interior North America to the east of the northern Rockies, may make slow further progress toward the northern/mid Atlantic Seaboard, while perhaps undergoing some amplification along an axis southward through the upper and middle Mississippi Valley by late Tuesday night. This may support modest surface wave development along a stalling cold front across the southeastern Great Plains through lower Ohio Valley, and contribute to suppression of mid-level ridging across northern portions of the eastern Gulf Coast states. Otherwise, mid-level ridging to the north of a prominent subtropical high, still centered over southern Mexico, is likely to build across the southern Rockies and adjacent Great Plains, downstream of a low over the southern mid- to subtropical latitudes of the eastern Pacific. Only a slow eastward progression of this low is forecast, to the south of mid/upper ridging building northeastward into British Columbia and the Pacific Northwest. ...Southeastern Great Plains into Tennessee Valley... There is continuing spread within the latest model output, but a consensus of guidance suggests that pre-cold frontal outflow, generated by convection today through tonight, will remain a notable feature into and through this period. It appears that the leading edge of this air mass may curve from parts of the southern Appalachians/Tennessee Valley toward the Ark-La-Tex at 12Z Tuesday. The extent to which this advances southward through the eastern Gulf Coast states on its eastern flank, while retreating northeastward through the lower Mississippi Valley on its western flank, remains unclear. However, it seems probable that it will become a focus for intensifying thunderstorm development by late Tuesday afternoon in response to boundary-layer destabilization along and to its south, and forcing for ascent aided by low-level warm advection. At the same time, a corridor of stronger pre-frontal surface heating across parts of northeastern Texas through north central Arkansas may become the focus for stronger convective development, in the presence of larger CAPE supported by steeper mid-level lapse rates. More strongly capping elevated mixed-layer air may continue to inhibit more than isolated thunderstorm initiation farther to southwest, along the dryline across central Texas into areas near/south of Del Rio TX. Strengthening shear with the approach of digging mid-level troughing on the southern fringe of the westerlies is likely provide support for a few supercells across the southeastern Great Plains, and upscale growing and organizing clusters propagating into the lower Mississippi Valley. There appears a consensus within the model output that the intersection of this activity with the preceding outflow boundary may ultimately provide the focus for the most prominent evolving cluster, which may pose a risk for widespread strong to severe gusts across parts of Arkansas through the lower Mississippi Valley by late Tuesday evening. Too many uncertainties exist to upgrade the categorical severe threat at this time, but this remains possible in later outlooks for this period. ..Kerr.. 04/27/2026 $$ = = = 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 3.28-Linux * Origin: Capitol City Online (1:2320/107) ----------------------------------------------------------- [Voltar]