318
ACUS02 KWNS 061730
SWODY2
SPC AC 061728

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1228 PM CDT Mon May 06 2024

Valid 071200Z - 081200Z

...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST
INDIANA INTO NORTHWEST AND CENTRAL OHIO...

...SUMMARY...
Scattered severe thunderstorms will be possible Tuesday from the
Mid-South northeastward into the Ohio Valley. A few tornadoes, large
to very large hail, and severe/damaging winds all appear possible,
particularly from northeast Indiana into northwest and central Ohio.

...Synopsis...
A mid/upper cyclone is forecast to remain largely in place over the
western Dakotas while continuing to occlude. A convectively
augmented shortwave trough will likely move through the base of this
cyclone, progressing from the Mid MS Valley quickly northeastward
into the Upper Midwest and Upper Great Lakes during the day. Primary
surface low will occlude beneath the parent cyclone, but a secondary
low will likely develop at the triple point, moving from the MN/IA
border vicinity east-northeastward across central/southern MN into
Lower MI. The cold front extending southward from this secondary low
is forecast to push eastward across the Mid MS and OH Valleys, while
the warm front shifts northeastward into Lower MI and the Upper OH
Valley.

...Mid-South/Mid Mississippi Valley into the Ohio Valley...
A decaying convective line will likely extend from southern WI
through western IL and into western portions of the Mid-South early
Tuesday morning. Buoyancy will be modest ahead of this line, which
will likely limit the severe potential. Even so, there is still a
low-probability chance for a few instances of hail and/or damaging
gusts, particularly along the southern end of the convective line in
the Mid-South vicinity where buoyancy is greatest.

The convective line is expected to make quick northeastward
progress, clearing the through the Lower OH Valley by the late
morning and much of the Middle OH Valley by the early afternoon. The
air mass is expected to recover quickly in its wake, with mid to
upper 60s dewpoints advecting in from the southwest. Additional
thunderstorm development is expected around 17-18Z across IL,
supported by both warm-air advection and increasing large-scale
ascent attendant to the approaching shortwave trough. This initial
activity will likely be elevated, but shear is strong enough to
support some more organized structures capable of hail. As the
downstream airmass across OH and IN destabilizes, these initial
storms will likely trend towards becoming more surface-based. Given
the strong vertical shear in place, the potential for supercells
will increase as storms become surface based. All severe hazards
will be possible with these supercells, including large hail and
tornadoes. The tornado threat is expected to maximize from northeast
IN into western and central OH during the late afternoon/early
evening, where the proximity to the warm front will contribute to
better low-level shear.

...Upper Midwest...
Despite relatively cool surface temperatures, cooling mid-levels
coupled with modest low-level moisture are expected to result in
airmass destabilization and modest buoyancy ahead of the triple
point and associated surface boundaries. Thunderstorm development is
anticipated both near the triple point, as well as along and
north/northeast of the occluded front. Much of the activity in the
vicinity of the occluded front will likely be elevated, but a few
stronger updrafts capable of hail are still possible. More
surface-based storms are possible near the triple point across
southern WI. Here, isolated hail and gusty winds may occur with the
more robust cores, and a brief tornado or two also appears possible.

...Mid-Atlantic...
Isolated to perhaps widely scattered thunderstorms may develop
Tuesday afternoon across parts of VA/NC, generally along/east of a
weak surface lee trough. Sufficient forecast instability and shear
should be present to support some threat for hail and strong winds
with any thunderstorms that form. The overall severe threat is
expected to remain fairly isolated/marginal.

...Lower Mississippi Valley/Deep South...
This region will be displaced south of the stronger forcing for
ascent, but moderate buoyancy and vertical shear still suggest there
is isolated severe potential with any storms that do form. Current
guidance suggests the greatest probability of storms exists across
MS and AL where the low-level moisture convergence is greatest.

...Central Texas...
The severe thunderstorm threat remains highly conditional across
parts of central TX Tuesday afternoon along/near a low-level
moisture gradient/sharpening dryline. Large-scale ascent will be
negligible, with thunderstorm initiation relying on surface
convergence. If any thunderstorms can form and persist, they
could become severe given a strongly unstable airmass. This scenario
remain too uncertain to add low severe probabilities with this
outlook.

..Mosier.. 05/06/2024

$$