SPC AC 141630

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1130 AM CDT Wed Aug 14 2019

   Valid 141630Z - 151200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
   CENTRAL/NORTHERN HIGH PLAINS...

   ...SUMMARY...
   Scattered severe thunderstorms with very large hail, a couple
   tornadoes, and damaging winds are possible across parts of the
   central and northern High Plains from late afternoon into tonight.

   ...Northern/central High Plains...
   Confidence in storm coverage and initiation corridors are lower
   today compared to yesterday. Surface dew points are drier this
   morning with 50s prevalent to low 60s in KS in the wake of
   yesterday's convective overturning. Nevertheless, persistent
   mid-level west-northwesterlies will maintain very steep lapse rates
   atop the residual boundary-layer moisture and should yield a plume
   of MLCAPE from 1500-2500 J/kg at peak heating from the Black
   Hills/eastern WY south across far eastern CO/western KS. 
    
   Forcing for ascent will be rather weak near the higher terrain and 
   southerly low-level flow dominates eastern CO at present. Convective
   initiation should be delayed until late afternoon and may be sparse
   in the central High Plains, with storm coverage beyond a cell or two
   highly questionable within the corridor most favorable for
   supercells. Still, effective bulk shear of 40-50 kt with relatively
   straight hodographs will support the risk of a couple supercells
   capable of producing isolated very large hail. The tornado threat
   will likely depend on a discrete cell interacting with the somewhat
   greater low-level shear/hodograph curvature expected near the
   CO/KS/NE border area along the east edge of the greater buoyancy. 

   Somewhat greater confidence in convective initiation is across
   southeast MT/northeast WY owing to peripheral influence of a minor
   shortwave trough approaching from the Canadian Rockies. Isolated to
   perhaps scattered storms should develop along the northern extent of
   the buoyancy plume. There is some signal for upscale growth into a
   small, increasingly elevated MCS downstream across portions of
   western SD/NE tonight as a 25-35 kt nocturnal low-level jet develops
   across the Panhandles to southwest NE. Isolated severe wind and hail
   will remain possible into the early overnight. 

   ...Central Gulf Coast to the Mid-Atlantic...
   The effective surface boundary, modulated by convective outflow,
   will continue to sag southward toward the Central Gulf Coast and
   southeastward toward the South/Mid-Atlantic coasts. The richer
   moisture (PW greater than 2 inches) and large buoyancy (MLCAPE of
   2500-3500 J/kg) should be confined to the eastern Carolinas
   southwestward into the central Gulf Coast. Vertical shear will be
   very weak and boundary/storm mergers will largely drive isolated
   downburst potential. Somewhat stronger deep-layer shear is expected
   farther north toward Chesapeake Bay, which could compensate some for
   the weaker buoyancy and poor mid-level lapse rates.

   ...Northern IN vicinity...
   A diffuse surface front will provide a focus for thunderstorm
   development this afternoon, as a minor mid-level impulse approaches
   from southern WI. Lingering low-level moisture and surface heating
   will support MLCAPE of 1000-1500 J/kg, while deep-layer vertical
   shear will be at least marginally favorable for a couple
   organized/supercell storms. Very weak low-level flow will greatly
   limit hodograph size/SRH magnitude, but there will be modest
   vertical vorticity along the surface boundary. A couple of storms
   with hail/wind near severe criteria and a brief tornado are all
   possible.

   ..Grams/Leitman.. 08/14/2019

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z