A Mesodiscussion is issued by the National Weather Service's Storm Prediction Center when there is a chance of a significant weather event impacting an area. These are routinely issued before weather watches or as updated to weather watches.

SPC MD 2304

MD 2304 Image

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...


LAT...LON   33109228 33369292 33739318 34019295 35099107 36788831
            37248713 37258625 36838569 36198571 35438616 34358762
            33928845 33358968 33299019 33169083 33139148 33109228 

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