SPC AC 141730

   Day 2 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1230 PM CDT Tue Jul 14 2020

   Valid 151200Z - 161200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF
   THE MID MS VALLEY VICINITY AND THE SOUTHERN/CENTRAL HIGH PLAINS...

   ...SUMMARY...
   Severe storms may occur Wednesday across parts of the mid
   Mississippi Valley, and over portions of the southern and central
   High Plains. Damaging winds and large hail should be the main
   hazards with these storms.

   ...Mid Mississippi Valley Vicinity...
   A large-scale upper trough over the northern/central Plains and
   central Canada will progress slowly eastward over the Great Lakes
   and Ontario on Wednesday. Convection will likely be ongoing
   Wednesday morning across some portion of eastern KS into MO in
   association with a low-level jet. These storms should weaken through
   the morning as the low-level jet gradually lessens, but they could
   still pose an isolated hail/wind threat.

   Renewed convective development appears likely by Wednesday afternoon
   from MO into IL as a remnant MCV and mid-level vorticity maximum
   provide sufficient large-scale ascent. The greatest severe risk
   should focus along/south of a front across the mid MS Valley, where
   diurnal destabilization of a moist low-level airmass should support
   MLCAPE reaching 2000-4000 J/kg by peak afternoon heating. Modestly
   enhanced mid-level winds associated with a low-amplitude shortwave
   trough along with a veering low-level wind profile will act to
   organize convection Wednesday afternoon/evening. Semi-discrete
   supercells may occur initially over parts of central/eastern MO into
   central IL, with both a large hail and damaging wind threat. With
   time, it appears that clustering will occur, and the damaging wind
   threat may increase with eastward extent across central/eastern IL
   through early Wednesday evening with one or more forward-propagating
   bows. This convection should weaken by late Wednesday evening across
   IN and far western KY as instability wanes with the onset of
   nocturnal cooling and strengthening convective inhibition.

   ...Southern/Central High Plains...
   A subtle mid-level impulse and modest easterly low-level flow should
   support scattered storm development across the higher terrain of
   southeastern CO and northeastern NM Wednesday afternoon. Steep
   mid-level lapse rates will overlie mid 50s to mid 60s F surface
   dewpoints, which combined with strong diurnal heating will likely
   result in the development of 2000-3000 J/kg of MLCAPE. Although
   low-level flow should remain modest, there will be enough mid-level
   west-northwesterly flow to support 30-40 kt of effective bulk shear,
   gradually weakening with southward extent across the southern High
   Plains. Initially high-based storms may be a mix of multicells and
   supercells, posing an isolated large hail and severe wind gust
   threat as they move slowly eastward. Some upscale growth into one or
   more small clusters appears possible through Wednesday evening, with
   a severe wind risk potentially continuing into parts of the OK/TX
   Panhandles before eventually weakening.

   A more conditional threat for isolated severe storms may exist
   along/north of a front extending across parts of northern OK into
   KS. However, latest guidance is trending away from robust storm
   development across this region from Wednesday evening into Thursday
   morning. Have trimmed severe probabilities generally southward
   across KS given this signal.

   ..Gleason.. 07/14/2020

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