SPC AC 050553

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1253 AM CDT Wed Aug 05 2020

   Valid 051200Z - 061200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE CENTRAL
   HIGH PLAINS REGION...

   ...SUMMARY...
   Strong to severe storms capable of strong wind gusts and large hail
   are possible this afternoon and evening over portions of the central
   High Plains.

   ...Synopsis...
   A weakly progressive upper pattern will exist over the U.S. today,
   with troughing expanding over the West, ridging moving across the
   Intermountain region toward the Plains, and a second trough crossing
   the Great Lakes/Midwest/Lower Mississippi Valley.

   At the surface, a generally weak/nondescript pattern will prevail,
   with high pressure over much of the eastern half of the country.  A
   weak baroclinic zone will linger from the southern Appalachians
   across the Gulf Coast states, and then extending northwestward
   across Texas, while lee troughing persists over the High Plains
   through the period.

   ...Central High Plains...
   Daytime heating of the modestly moist (50s dewpoints) boundary layer
   across the central High Plains region will once again support
   moderate destabilization from southeast Wyoming and the Nebraska
   Panhandle south to northeastern New Mexico.  Weak/subtle short-wave
   troughing within moderate west-northwesterly flow is expected to
   reach the High Plains during the afternoon, supporting
   isolated/robust convective development.  With low-level
   southeasterlies across the region, veering/increasing flow with
   height will result in shear sufficient to augment convective
   intensity locally -- with large hail and locally damaging winds
   expected.

   With time, storms are forecast to merge into one or more
   east-southeastward-moving clusters, and cross eastern Colorado and
   portions of the Nebraska Panhandle.  Risk for damaging winds may
   persist locally, before diurnal convective weakening commences.

   ...Eastern SD and southwestern MN into the mid MO valley...
   An upper perturbation now crossing North Dakota will continue moving
   southeastward across the eastern Dakotas through the afternoon,
   possibly accompanied by weak/remnant convection.  Some regeneration
   of convection may occur over eastern South Dakota and southwestern
   Minnesota during the afternoon, as moderate destabilization occurs,
   with isolated storms possibly spreading into northeastern Nebraska
   and northwestern Iowa with time.  With moderate northwesterly flow
   aloft atop this region, a stronger storm or two may be capable of
   producing gusty/damaging winds and marginal hail, before convection
   diminishes during the evening.

   ...Portions of eastern/southeastern TX into southwestern LA...
   Remnants of overnight convection -- and possibly an MCV -- should
   continue moving southeastward into/across East Texas into the
   afternoon.  Lingering/weak convection may then reintensify during
   the afternoon, spreading into southeast Texas and southwestern
   Louisiana, as diurnal heating contributes to moderate
   destabilization.  With moderate (25 to 35 kt) northwesterly flow at
   mid levels spreading into the area, atop low-level southerlies,
   shear may prove strong enough for a few storms to organize/become
   severe.  If some upscale/linear growth can occur, attendant risk for
   gusty/damaging winds and marginal hail may spread as far
   southeastward as the western Gulf coastal waters by early evening,
   before storms dissipate.

   ..Goss/Wendt.. 08/05/2020

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