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

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