SPC AC 290058

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0758 PM CDT Sun May 28 2017

   Valid 290100Z - 291200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM DEEP SOUTH
   TEXAS TO THE LOWER MISSISSIPPI VALLEY...

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE COASTAL
   CAROLINAS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FROM THE RIO
   GRANDE VALLEY TO THE CENTRAL GULF COAST...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS THE
   EASTERN/CENTRAL CAROLINAS...

   ...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   INDIANA AND OHIO...

   ...SUMMARY...
   Severe thunderstorms capable of large hail and damaging winds will
   remain possible this evening into tonight across portions of
   southern/central Texas and Louisiana. Elsewhere, a few severe
   storms, primarily capable of damaging winds, will move east across
   the coastal Carolinas. A few lingering strong storms may produce
   gusty winds over portions of Indiana and Ohio this evening.

   ...Deep South Texas to Louisiana...
   A corridor of strong to severe thunderstorms persists this evening
   from the Rio Grande Valley northeastward to northern Louisiana.
   Along the northeastern edge of this corridor, a downwind-propagating
   convective system has organized, and the air mass ahead of it is
   characterized by moderate mixed-layer buoyancy and adequate
   deep-layer shear. Therefore, this line should continue accelerating
   southeast through the evening, with an attendant threat of damaging
   winds, a couple instances of large hail, and perhaps a tornado.

   Farther southwest, while mid-level flow (and resultant effective
   shear) lessen, strong buoyancy (e.g., mixed-layer CAPE around 3000
   J/kg on the CRP 00Z sounding) is fostering renewed convective
   development along outflow boundaries. This development is resulting
   in a general south/southeast propagation. Considering the ample
   instability ahead of these storms, and modest (yet adequate)
   deep-layer shear, clusters of strong/severe storms will likely
   continue into the overnight as they push south/southeast. Thus, the
   15-percent wind/hail probabilities are expanded to include more of
   south Texas.

   ...Coastal Carolinas...
   Within a moderately unstable environment, convection has organized
   upscale into several small bowing segments accelerating towards the
   coast. The downstream air mass remains favorable for damaging winds,
   with the 00Z CHS sounding sampling plentiful DCAPE (around 1300
   J/kg) and 40-50 kt westerlies between 700 and 500mb. Therefore, the
   slight risk is adjusted southward to capture the ongoing severe
   potential here.

   ...Ohio and Indiana...
   Several small clusters of strong to marginally severe convection are
   advancing eastward this evening, aided by residual surface-based
   buoyancy and modest low/mid-level westerlies. With the loss of
   diurnal heating, low-level instability will wane and overall
   convective intensity will further diminish. However, an isolated
   strong wind gust and/or marginally severe hail report may remain
   possible for the next hour or two.

   ..Picca.. 05/29/2017

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