Valid 011630Z – 021200Z
…THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS AR/SOUTHERN MO
Isolated severe thunderstorms are possible across parts of the
Arkansas and southern Missouri vicinity, mainly this evening.
A modifying low-level moisture plume (characterized by 50s to low
60s surface dew points) emanating from the western Gulf will
gradually expand across the south-central states through the period.
On the eastern periphery of the moisture plume within a warm
advection regime, convection is expected to form towards 00Z from AR
through the Mid-MS Valley. Upstream development is also possible in
the southwest MO vicinity later in the evening as a cold front
impinges on the northwest extent of the moisture plume.
Mid-level lapse rates are rather steep across the region, supporting
a risk for hail production as MUCAPE increases to 500-1000 J/kg.
However, deep-layer shear will be modest, especially with northern
extent, suggesting that supercells should struggle to be sustained
north of AR and that a cluster convective mode will dominate. A
relatively dry sub-cloud region across eastern AR and adjacent
portions of the Lower MS Valley may support isolated strong wind
gusts despite convection largely being rooted above the
boundary-layer here. The marginal severe risk should subside
overnight/early morning Monday.