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Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0200 PM CST Mon Nov 18 2024

Valid 182000Z - 191200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
EASTERN TEXAS AND LOUISIANA...

...SUMMARY...
A risk for a couple of tornadoes and damaging winds is forecast into
this evening from parts of east Texas into Louisiana and the central
Plains this evening.

...20z Update...
Across portions of eastern TX and western LA, scattered cloud breaks
and low-level warm advection are supporting destabilization along
and ahead of the main frontal precipitation band. As the front
continues east, updrafts along the front should strengthen, with
gradual storm development in the form of a QLCS. Ahead of the front,
the latest forecast guidance also shows a couple of more discrete
updrafts may eventually mature as temperatures warm. With strong
deep-layer shear in place, storm organization into supercells
capable of damaging gusts and a couple tornadoes is possible.

Across portions of northeast LA and southern MS, buoyancy remains
fairly limited. However, as the front/QLCS approaches, a few
stronger updrafts may persist. Given the strong low-level shear,
damaging gusts and a tornado or two will be possible into this
evening, though the magnitude and coverage of the threat remain
unclear.

...Central Plains and MO Valley...
Widespread cloud cover and precipitation have been slow to erode
ahead of the mid-level dryslot associated with the advancing
mid-level trough. While buoyancy is expected to remain very weak
(~300-500 J/kg of low-level MUCAPE), recent radar and satellite
imagery show low-topped convective bands have emerged in a narrow
area of cloud-breaks over south-central KS. Weak heating and dynamic
cooling beneath the upper trough could support enough buoyancy for
low-topped thunderstorms capable of isolated damaging gusts or a
brief tornado through the remainder of this afternoon.

..Lyons.. 11/18/2024

.PREV DISCUSSION... /ISSUED 1025 AM CST Mon Nov 18 2024/

...East Texas into the Lower Mississippi Valley...
Water-vapor imagery late this morning shows a negatively tilted
mid-level trough over the southern High Plains rapidly moving
northeast, and this feature will reach the Upper Midwest by early
Tuesday morning.  The southern portion of an ongoing convective line
may continue to weaken across eastern/northeastern TX through the
early afternoon.  Models continue to suggest a risk for pre-squall
line updrafts developing in the warm sector this afternoon from east
TX into LA where MLCAPE may reach up to 500-1000 J/kg with daytime
heating.  Mid-level lapse rates will remain poor and the stronger
forcing for ascent will gradually beco*e displaced by late afternoon
across this region.  However, strong flow fields will support a risk
for supercells with the stronger updrafts that develop.  Uncertainty
remains regarding the overall coverage (isolated) of potential
supercells and their associated severe risk.  Have left this portion
of the outlook area unchanged.

...Central Plains/Ozarks into the Mid Missouri Valley...
Morning surface analysis places a low over northwest OK with the
zone of strongest pressure falls extending northeast into northeast
KS where the low is forecast to track later today.  A mid-level
dryslot over the southern Great Plains will continue to shift
northeastward into KS this afternoon and aid in some weak
surface-based destabilization.  

In wake of morning showers/thunderstorms over KS, it remains
possible sufficient weak destabilization occurs by mid-late
afternoon immediately ahead of the low from central KS and quickly
spreading northeastward into the MO Valley.  Confidence is reserved
regarding overall coverage of robust storm development due in part
to extensive low cloud cover inhibiting destabilization, but it
seems possible a couple of strong to severe thunderstorms may
develop and yield an isolated risk for gusty winds and perhaps a
tornado.