SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0146 PM CST Wed Dec 23 2020 Valid 232000Z - 241200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE WESTERN AND CENTRAL GULF COAST REGION... ...SUMMARY... A threat for damaging wind gusts and a few tornadoes will shift eastward across the Lower Mississippi Valley and central Gulf Coast region this afternoon through tonight. ...Discussion... No changes appear necessary to the ongoing outlook, as forecast reasoning and areas highlighted in prior outlooks continue to appear on track. Thunderstorms should develop across the lower Mississippi Valley region late this afternoon, and then spread across the central Gulf Coast region, with isolated severe weather potential. ..Goss.. 12/23/2020 .PREV DISCUSSION... /ISSUED 1030 AM CST Wed Dec 23 2020/ ...Lower Mississippi Valley/Gulf Coast States... Steady height falls are expected today as a base-embedded/positive-tilt portion of an upper trough spreads toward the ArkLaTex/Lower Mississippi Valley through tonight, with a cold front moving southeastward across the region. Within the warm sector, showers/some thunderstorms should gradually increase this afternoon from the middle/upper Texas coast into Louisiana. Although cloud cover may remain semi-prevalent ahead of the cold front, a moistening/warming boundary layer and gradual erosion of convective inhibition suggests that this activity may gradually become more surface-based and potentially intensify as early as mid/late afternoon, although the cloud cover/initially modest forcing for ascent are points of temporal uncertainty. Another zone of intensifying thunderstorm development is expected immediately near the cold front as it moves southeastward across the ArkLaTex/Mid-South late this afternoon/early evening. Moisture/buoyancy will be comparatively lesser with northward extend, but with very strong southwesterly winds through a deep layer, at least some potential for damaging winds/possibly a brief tornado will exist with near-surface-based storms late this afternoon into tonight. Overall, convection will become increasing prevalent/organized this evening, including linearly organized convection near the cold front as well as front/line-preceding semi-discrete development including supercells, with all of this activity tending to merge overnight. Damaging winds and a couple of tornadoes will be possible, particularly across parts of Louisiana and far southern Mississippi. A severe risk may exist as far east as the Florida Panhandle/southern Alabama late tonight into early Thursday.
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