A Severe Weather Watch May Be Needed Over the Next Few Hours Over the Southern Parts of the Area

| December 30, 2021 @ 10:40 am

The latest Mesoscale Discussion is out from the Storm Prediction Center, and it states that the potential for severe storms may start to rise with the heating of the day. Either a severe thunderstorm or a tornado watch may be needed over the next couple of hours.

SUMMARY… A gradual uptick in severe potential is possible into the early afternoon hours. Damaging gusts would be the primary severe threat, though a tornado or two is also possible. A WW issuance may eventually be needed over the next couple of hours.

DISCUSSION… Multiple discrete/semi-discrete west-east progressing storms have been moving roughly parallel to a southward-sagging surface cold front over the past couple of hours. In the past hour, some of these storms have deviated to the right slightly, with KBMX and MRMS mosaic radar showing modest low and mid-level rotation with storms in central AL. Surface temperatures ahead of these storms are at least in the mid 70s F, with near 70 F dewpoints, contributing to 1000 J/kg MLCAPE given 6-6.5 C/km mid-level lapse rates (per 16Z mesoanalysis). Though parallel to the surface cold front, 50 kts of effective bulk shear suggests that potential exists for the more intense, sustained updrafts to become or remain organized.

While overall deep-layer ascent is weak, ample diurnal heating ahead of these storms may foster enough lift and buoyancy to pose a severe threat. Given veered low-level wind profiles (evident via recent MXX and JGX VWPs), damaging gusts are anticipated to be the primary threat, though a tornado also cannot be ruled out given nearly 150 m2/s2 0-1 km SRH. The main question is when the bulk of the severe threat will occur. A sparse severe threat exists at present. However, since the uptick in severe may be gradual, a WW may not be needed for at least a few more hours. Convective trends will continue to be monitored for the need of a WW issuance.

Category: Alabama's Weather, ALL POSTS, Severe Weather

About the Author ()

Scott Martin is an operational meteorologist, professional graphic artist, musician, husband, and father. Not only is Scott a member of the National Weather Association, but he is also the Central Alabama Chapter of the NWA president. Scott is also the co-founder of Racecast Weather, which provides forecasts for many racing series across the USA. He also supplies forecasts for the BassMaster Elite Series events including the BassMaster Classic.

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