794
ACUS03 KWNS 050731
SWODY3
SPC AC 050730

Day 3 Convective Outlook
NWS Storm Prediction Center Norman OK
0230 AM CDT Sun May 05 2024

Valid 071200Z - 081200Z

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
THE MID-SOUTH INTO THE OHIO VALLEY...

...SUMMARY...
Scattered severe thunderstorms appear possible Tuesday from the
Mid-South northeastward into parts of the Ohio Valley.

...Synopsis...
A large, closed upper cyclone over the northern Plains should move
little on Tuesday. A lead mid-level shortwave trough with attendant
enhanced mid-level jet is forecast to move quickly northeastward
across the Upper Midwest and Great Lakes through the day. The
southern fringe of this shortwave trough and modest large-scale
ascent should overspread parts of the Mid-South into the OH Valley
Tuesday afternoon. At the surface, a deep low over ND should slowly
occlude, while a weak secondary low develops northeastward in tandem
with the shortwave trough across parts of the Upper Midwest and
Great Lakes. A moist and unstable airmass should exist along and
southeast of a convectively reinforced surface front, generally
extending northeastward from the ArkLaTex vicinity into parts of the
mid MS and OH Valleys.

...Mid-South into the Ohio Valley...
A line of thunderstorms will probably be ongoing Tuesday morning
over parts of AR/MO/IL, associated with convection that developed on
Monday across the Plains. This activity may tend to weaken though
the morning. But, it could still pose an isolated strong/gusty wind
threat. Weak to moderate instability should develop ahead of and to
the southwest of these early-day thunderstorms, with greater
instability forecast across the Mid-South and lower OH Valley.
Deep-layer shear is forecast to be strong enough to support
organized convection, including some supercells. However, with
mid-level flow generally aligned with the forecast position of the
surface boundary, tendency may be for clusters/bowing line segments
to prevail.

Regardless, scattered strong to severe thunderstorms should spread
east-northeastward across the OH Valley Tuesday afternoon and
evening, posing a threat for mainly damaging winds and severe hail.
Across the Mid-South/TN Valley into AR, the severe threat appears
more conditional, owing to this region generally being displaced to
the south of the better forcing aloft. An isolated threat for severe
hail may develop late in the period (early Wednesday morning) across
the Ozarks as low-level flow/ascent increases with a strengthening
low-level jet.

Given latest model trends and the likelihood for morning convection
across the mid MS Valley, it appears that the potential for
appreciable destabilization and severe thunderstorms is lower across
much of IA, MO, and IL. Have therefore reduced severe probabilities
across these areas.

..Gleason.. 05/05/2024

$$