SPC AC 291624

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1124 AM CDT Sun May 29 2022

   Valid 291630Z - 301200Z

   ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
   INTO TONIGHT FROM NORTHEAST NE INTO CENTRAL MN...

   ...SUMMARY...
   Severe thunderstorm gusts of 60 to 85 mph, hail to near baseball
   size, and a few tornadoes are possible this afternoon and tonight
   from parts of Nebraska northeastward into southwestern and central
   Minnesota.

   ...NE to MN this afternoon through tonight...
   In the wake of a lead shortwave trough, a surface cold front has
   progressed southward into southeast CO/northwest KS/central NE. 
   This boundary is expected to stall today, in response to renewed lee
   cyclogenesis in the vicinity of southeast CO/western KS, downstream
   from the deep midlevel trough moving eastward from the Great Basin. 
   The lee cyclogenesis will maintain strong southerly low-level flow
   across KS/OK and northward transport of mid 60s boundary-layer
   dewpoints into the stalling frontal zone across NE.  Farther
   northeast, the warm sector will be maintained today into MN, in the
   wake of morning convection.  Additional storm development will be
   possible this afternoon along the stalled front and near the remnant
   initial surface cyclone, from northwest MN southward into eastern
   SD.  Where storm development is more probable, moderate-strong
   buoyancy is expected in pockets of stronger surface heating across
   western MN.  Deep-layer vertical shear will be sufficient for
   supercells, though there are some weaknesses in forecast hodograph
   structures across this area this afternoon/evening.  Large hail,
   damaging gusts, and a couple of tornadoes will be possible.

   The more substantial severe threat should evolve this evening
   starting across NE, and continue overnight across southeast SD,
   northwest IA, and southwest MN.  Two potential convective modes are
   evident:  1) isolated supercell development this evening/early
   tonight along the stalled front in the vicinity of northeast NE, and
   2) cluster/supercell evolution of initially post-frontal convection
   across CO/WY this afternoon into NE this evening.  Any isolated
   supercell development this evening will be focused along the stalled
   front in NE, with the potential for very large hail (baseball size
   or larger) and a few tornadoes.  The ongoing convection over
   northwest CO will likely spread eastward in the zone of ascent
   preceding the primary shortwave trough over the Great Basin.  Storms
   in this zone will pose a marginal wind/hail threat this afternoon
   across northern CO/southern WY, with storm intensification more
   probable by late afternoon/evening as the convection/forcing for
   ascent encounter richer moisture/larger buoyancy across
   western/central NE (along and to the immediate cool side of the
   front).  There will be the potential for both upscale growth of
   clusters and embedded supercells, with the potential to produce a
   few tornadoes, very large hail, and swaths of 60-85 mph outflow
   winds tonight.

   ..Thompson/Dean.. 05/29/2022

   CLICK TO GET WUUS01 PTSDY1 PRODUCT

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