Mesoscale Discussion 1011
NWS Storm Prediction Center Norman OK
0806 PM CDT Thu Jun 06 2019
Areas affected...east-central MS...central AL
Concerning...Severe potential...Watch unlikely
Valid 070106Z - 070200Z
Probability of Watch Issuance...20 percent
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.
..Smith/Grams.. 06/07/2019