SPC AC 010559

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1259 AM CDT Mon Jul 01 2024

   Valid 011200Z - 021200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER PARTS OF THE
   CENTRAL AND NORTHERN PLAINS...

   ...SUMMARY...
   Severe thunderstorms will be possible today across the
   northern/central Plains centered over Nebraska and South Dakota.
   Areas of damaging winds and sporadic hail will be possible.

   ...Synopsis...
   An upper-level trough will progress eastward into the northern and
   central Plains today. The upper-level ridge within the southern
   Plains will weaken in response and shift gradually eastward as well.
   At the surface, the anticyclone within the East will broaden,
   pushing a surface boundary farther into Southeast. Within the
   broader lee trough, a surface low is forecast to deepen near the
   CO/KS/NE border region and shift eastward through the afternoon. The
   combination of the surface high to the east and the deepening
   surface cyclone in the central Plains will advect rich low-level
   moisture northward through the day into south-central and southeast
   Nebraska and perhaps somewhat farther northwestward. Southerly flow
   within the northern Plains will also move low 60s F dewpoints
   currently in Kansas into the Dakotas.

   ...Central Plains...
   Based on surface observations Sunday evening, upper 60s to low 70s F
   dewpoints appear probable to reach portions of Nebraska (potentially
   as far west as the Panhandle). Though some form of convection
   currently in eastern Colorado/western Nebraska may be ongoing early
   in the day Monday, this activity is forecast to weaken and move east
   by early afternoon. Thereafter, very strong heating is expected west
   of a dryline feature. Modest height falls should aid in thunderstorm
   development near the surface low and northward-advancing warm front.
   Initial development should be supercellular given large buoyancy
   (2500-3000 J/kg MLCAPE) and 45-55 kts of effective shear. Low-level
   shear enhancement near the warm front will promote some risk of
   tornadoes so long as convection remains discrete. Large hail and
   severe winds will also be possible. 2+ inch hail could occur, but
   probability appears low due to warm temperatures within the hail
   growth zone and high freezing levels. Weaker shear near the anvil
   levels as well as somewhat high temperature-dewpoint spreads should
   lead to quick upscale growth. This transition to linear mode will be
   accompanied by an increase in severe wind threat, some potentially
   75+ mph.

   There is potential for storm development along the remnant surface
   front/outflow boundary into eastern Kansas. Should a storm form, it
   would likely be severe. With limited background ascent this far
   south, confidence in storm initiation is quite low.

   ...Northern Plains...
   Stronger mid-level ascent in combination with a north-south oriented
   boundary will promote scattered storms across the region. Surface
   heating will be less on account of cloud cover, but sufficient
   low-level moisture will bring around 1500 J/kg MLCAPE. Though 40-45
   kts of shear will be across the boundary, forcing should promote
   decidedly more linear storm modes than farther south. Large hail and
   severe winds will the be primary threats. A tornado or two could
   occur given the ambient vorticity along the boundary.

   ...North Florida into Georgia and coastal South Carolina...
   Ongoing convection Sunday evening may leave some cloud debris
   present into Monday morning. Surface heating will be most pronounced
   north of the remaining clouds. MLCAPE of perhaps near 3000 J/kg
   appears possible by the afternoon. Mid-level lapse rates will be
   weak, as will effective shear (around 20-25 kts), but a few damaging
   gusts are possible especially with any clusters that may form.

   ..Wendt/Squitieri.. 07/01/2024

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