Mesoscale Discussion 2304
NWS Storm Prediction Center Norman OK
1050 AM CST Sat Dec 09 2023
Areas affected…Southern/eastern AR…western KY…western/middle TN…northern MS…northwest AL
Concerning…Severe potential…Watch likely
Valid 091650Z - 091845Z
Probability of Watch Issuance…95 percent
SUMMARY…The severe threat will increase with time, with all severe hazards becoming possible by this afternoon. Eventual watch issuance is likely.
DISCUSSION…A cluster of storms from northeast AR into southwest KY has intensified somewhat over the last 1-2 hours. This convection is likely somewhat elevated, given its relatively fast motion to the northeast and the currently stable appearance boundary-layer clouds on visible satellite across the warm sector to the immediate south. However, MUCAPE of 500-1000 J/kg, relatively cold temperatures aloft, and favorable deep-layer shear could support an isolated short-term hail threat with the strongest elevated storms.
Gradual diurnal heating of an increasingly moist warm sector will continue to remove remaining MLCINH through the morning, with an increase in surface-based storm development expected by midday to early afternoon. MLCAPE of 1000-2000 J/kg (greater with southwest extent) and effective shear of 50-60 kt will support organized convection. The environment will support the development and sustenance of supercells, though deep-layer flow largely parallel to the approaching cold front may result in a complex storm mode, with both linear and embedded cellular elements.
There will be a tendency for stronger low-level flow to gradually weaken from the southwest with time, but low-level shear/SRH will remain sufficient to support a tornado threat with any sustained supercells later this afternoon. Otherwise, large hail will remain a threat, and damaging-wind potential will become an increasing concern as storm coverage increases. Eventual watch issuance is likely by early afternoon, and perhaps sooner if ongoing attempts at initiation over central AR begin to mature late this morning.
..Dean/Guyer.. 12/09/2023
…Please see www.spc.noaa.gov for graphic product…
ATTN…WFO…LMK…OHX…BMX…HUN…PAH…MEG…JAN…LZK…SHV…
LAT…LON33109228 33369292 33739318 34019295 35099107 36788831 37248713 37258625 36838569 36198571 35438616 34358762 33928845 33358968 33299019 33169083 33139148 33109228
https://www.spc.noaa.gov/products/md/md2304.html