SPC AC 110734

   Day 3 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0234 AM CDT Mon Apr 11 2022

   Valid 131200Z - 141200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS MUCH OF
   THE LOWER/MID MISSISSIPPI VALLEY INTO THE MIDWEST...

   ...SUMMARY...
   Scattered to numerous severe thunderstorms appear likely across a
   large portion of the lower/mid Mississippi Valley into the Midwest,
   Ohio Valley, and Southeast on Wednesday. Large to very large hail,
   damaging winds and tornadoes will all be possible. Strong tornadoes
   may occur.

   ...Synopsis...
   An upper trough/low will continue to eject eastward from the Plains
   across much of the MS Valley, Midwest and Great Lakes regions on
   Wednesday. A surface low is likewise expected to advance generally
   eastward across the Upper Midwest/Great Lakes through the period. A
   trailing cold front will sweep eastward Wednesday across much of the
   MS/OH Valleys and Southeast as well.

   ...Mississippi Valley into the Midwest/Ohio Valley and Southeast...
   A substantial severe threat is evident for a large part of these
   regions ahead of the cold front. Pronounced large-scale ascent
   associated with the negatively tilted upper trough will likely
   overspread the warm sector through the day. 60s surface dewpoints
   will be present ahead of the front, with greater low-level moisture
   likely in place from the lower OH Valley/Mid-South into the lower MS
   Valley and Southeast. Diurnal heating of this airmass and the
   continued presence of steepened lapse rates aloft should allow for
   moderate to strong instability to develop by Wednesday afternoon.
   Deep-layer shear generally in excess of 45-50 kt will support
   organized severe thunderstorms, and low-level shear is also forecast
   to be quite strong. Pre-frontal convection appears possible across
   parts of the Mid-South and lower MS Valley vicinity through the day.
   If this occurs, then supercells posing a threat for all severe
   hazards, including strong tornadoes, would be likely. Linear
   convection is also expected to develop along much of the length of
   the front, and this activity will pose a threat for both damaging
   winds and QLCS tornadoes as it spreads eastward Wednesday afternoon
   and evening.

   Have opted to include a broad Enhanced Risk to account for numerous
   to potentially widespread damaging winds, and several tornadoes. The
   main uncertainty precluding greater severe probabilities at this
   time is the possible effect of early-day convection across the lower
   MS Valley/Mid-South on prospects for substantial destabilization
   later in the afternoon. Given the strong flow and sufficient
   instability forecast, at least an isolated severe threat should
   continue with eastward extent across the OH Valley, TN Valley, and
   Southeast Wednesday night.

   ..Gleason.. 04/11/2022

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