SPC AC 161728

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1228 PM CDT Tue Apr 16 2024

   Valid 171200Z - 181200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTHEAST INDIANA
   INTO SOUTHEAST LOWER MICHIGAN AND MUCH OF OHIO...

   ...SUMMARY...
   Scattered severe thunderstorms are possible Wednesday afternoon and
   evening from southern Lower Michigan into parts of the Ohio Valley.
   A more isolated severe threat may materialize across parts of
   Tennessee Valley into the Southwest as well as parts of the
   east-central Plains and Ozark Plateau.

   ...Synopsis...
   The upper-level wave and attendant surface low currently over the
   central Plains/Midwest are forecast to weaken over the next 24-48
   hours as they gradually lift to the northeast. A trailing surface
   cold front associated with the low is forecast to push east across
   the Great Lakes region through the day it becomes increasingly
   influenced by mean westerly flow. This boundary should be the focus
   for strong to severe thunderstorm development by late morning/early
   afternoon across IN/OH and lower MI. Additional thunderstorm
   development is anticipated by peak heating across portions of the TN
   Valley as a residual outflow boundary migrates east. To the west
   across the Plains, a warm advection regime should become established
   by early evening as a surface low begins to deepen ahead of an
   approaching upper-level wave. Isolated strong to severe
   thunderstorms are possible within the warm advection regime across
   parts of the Ozarks into the east-central Plains. 

   ...Midwest/Great Lakes...
   Broken cloud cover is anticipated Wednesday morning across the
   Midwest/Great Lakes as a mid-level dry slot overspreads the region
   in the wake of Tuesday night's convection. The north/northeast track
   of the decaying surface low should allow for low to mid 60s
   dewpoints to spread north into IN/OH and lower MI by late morning
   ahead of the approaching cold front. Thunderstorm development may
   occur by mid-morning across portions of IN, but the development and
   intensification of any convection will be dependent on the degree of
   subsidence within the dry slot. Diurnal heating of the low-level air
   mass should allow for 1000-2000 J/kg SBCAPE by early afternoon with
   decreasing inhibition. Consequently, more robust convection is
   likely by early afternoon across lower MI into western OH.
   Deep-layer flow off the front should favor initially discrete cells
   within a broken line of storms with an attendant hail and tornado
   risk. Steepening low-level lapse rates, combined with 40-50 knot
   mid-level flow, should support an increasing damaging wind threat by
   late afternoon. Upscale growth into one or more clusters is probable
   by late afternoon into the evening hours across eastern OH and far
   western PA given strong forcing along the front and similar storm
   and boundary motions. Further south into the OH River Valley,
   thunderstorm development is less certain given increasing
   displacement from the stronger forcing for ascent. However, a
   conditionally favorable environment for organized convection is
   forecast, which should support a more isolated severe threat. 

   ...Tennessee Valley region...
   A residual outflow boundary from Tuesday night's convection is
   expected to push east through the morning hours, reaching the
   eastern TN Valley into northern AL/MS by peak heating. Thunderstorm
   development and/or re-intensification is possible - especially
   across AL/MS/GA where latest CAMs show reasonable agreement in
   redevelopment as SBCAPE increases to around 1500 J/kg. While
   low-level flow is forecast to be weak, 30-40 knot westerlies aloft,
   combined with steepening low-level lapse rates by late afternoon,
   should support a few stronger cells/clusters with an attendant
   hail/wind risk. 

   ...Southwest Missouri to Northeast Kansas...
   An upper disturbance currently approaching northern MT is forecast
   to migrate southeast over the next 48 hours. Surface pressure falls
   over the Plains in response to the approach of this feature will
   strengthen southerly low/mid-level winds on the western periphery of
   a warm/moist air mass over the southern Plains/lower MS Valley -
   especially by early evening as the nocturnal jet strengthens.
   Concurrently, a cold air mass will begin migrating south along the
   High Plains. Thunderstorms may develop within the warm advection
   regime on the northern fringe of the returning moisture during the
   00-06 UTC period across parts of the Ozark Plateau. A second round
   is probable later overnight (during the 08-12 UTC period) as the
   cold front impinges on the returning moisture across northeast KS.
   For both regimes, sufficient deep-layer flow should be in place to
   support organized cells with a severe hail risk.

   ..Moore.. 04/16/2024

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