SPC Mesoscale Discussion: Severe Potential… Watch Unlikely

SUMMARY…Transient supercells will be capable of intermittent strengthening of low-level mesocyclones with the strongest updrafts. A brief/weak tornado is possible this evening. The isolated character and magnitude of the threat will probably preclude the need for a small tornado watch.

DISCUSSION…Radar mosaic shows a band of convection, from north-central MS southeastward into west-central AL, with embedded discrete cores immediately east of a surface low over east-central MS. Surface observations show backed southeasterly surface winds east of the ongoing convective activity. KBMX VAD show the low-level winds acting to enlarge the hodograph (around 200 m2/s2 0-1km SRH). The 00z Birmingham, AL raob showed a very moist/deep boundary layer with just over 100 J/kg MLCAPE, all located below 500mb. The equilibrium level (based on a 100mb mean parcel) is just below the -20 degrees C level and would likely not support much lightning with the stronger updrafts. The moist-adiabatic lapse rate/pseudo tropical profile will not cool substantially during the evening. As a belt of modestly strong, southerly 850mb flow shifts northward across central and then into north-central AL and northwest GA through the late evening, expecting episodic strengthening of small mesocyclones in the very moist airmass over far east-central MS in the near term and later into parts of central AL. A brief/weak tornado may accompany the strongest circulations.

Tags: MesoScaleDiscussion

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