SPC 2000Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0149 PM CST Fri Nov 27 2020 Valid 272000Z - 281200Z ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF THE WESTERN AND CENTRAL GULF COAST REGION... ...SUMMARY... Isolated, marginally severe thunderstorms are possible from South Texas to southern Mississippi today. ...20z Update - Western and Central Gulf Coast... The only changes to the ongoing Marginal risk area have been to remove northern portions of the area from TX into LA/MS based on the current position of the surface front. Otherwise, the ongoing forecast remains on track. Refer to MCD 1817 and the previous outlook below for more details. ..Leitman.. 11/27/2020 .PREV DISCUSSION... /ISSUED 1020 AM CST Fri Nov 27 2020/ ...Western and Central Gulf Coast... Morning water vapor loop shows a compact upper low over AZ moving toward the southern Plains. Relatively fast west-southwesterly flow aloft extends from northern Mexico into parts of TX/LA/MS/AL where low-level warm/moist advection is resulting in scattered showers and thunderstorms. This activity is forecast to continue through much of the day as a weak surface cold front sags southward across the region. Forecast soundings show MUCAPE values around 1000 J/kg from southern AL into LA, with higher values farther southwest in TX. This, combined with sufficient deep-layer shear may result in transient rotating/bowing structures and an associated risk of gusty winds or a brief spinup. However, low-level flow is weak and lapse rates are not particularly steep. Therefore, the overall severe threat remains marginal.
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