SPC AC 291237

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0737 AM CDT Fri Apr 29 2022

   Valid 291300Z - 301200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS SOUTH-CENTRAL
   AND SOUTHEAST NE TO NORTH-CENTRAL AND NORTHEAST KS...

   ...SUMMARY...
   A multi-outcome severe weather episode is forecast this afternoon
   into tonight across the central Great Plains vicinity.
   Conditionally, the threat for significant severe weather intensities
   is apparent which includes destructive wind and hail, along with a
   few strong tornadoes.

   ...Synopsis...
   A negative-tilt shortwave trough over the northern/central Rockies
   will eject onto the central Great Plains by this evening before
   evolving into a closed low near the Mid-MO Valley overnight. A
   strong mid-level speed max in excess of 70 kts at 500-mb will eject
   through the basal portion tonight. Lee cyclone near the CO/KS/NE
   border will deepen as it tracks east towards far north-central KS
   through 00Z, before arcing northeast into the Mid-MO Valley as it
   weakens slightly overnight. At 00Z, a sharp dryline will arc
   south-southwest from this cyclone, with a pronounced cold front
   sweeping southeast across western KS. This cold front will
   progressively overtake the dryline from north to south through
   tonight. 

   ...Central Great Plains vicinity...
   Multiple forecast scenarios are expected to unfold this afternoon
   and continue into tonight. Sufficient mesoscale confidence exists to
   warrant a wind-driven category 4/Moderate Risk along the NE/KS
   border, but not yet enough to include higher tornado probabilities
   farther south.

   Two primary corridors of scattered elevated thunderstorms are
   ongoing. The first across eastern KS into the Lower MO Valley will
   likely shift east and decay as a stout elevated mixed-layer expands
   east-northeast today. The second across west-central NE to the
   west-northwest of the initially quasi-stationary frontal zone may
   persist with continued isentropic ascent. Sustained severe
   thunderstorm development is most likely to occur to the south and
   east of this corridor of early-day convection near the surface
   cyclone track and associated frontal zone. Large-scale ascent will
   become quite strong along the northwest periphery of near 60 F
   surface dew points. Deep-layer shear profiles will initially be
   modest and tend to favor a cluster convective mode with a mix of
   severe hail and wind. In the late afternoon to early evening, this
   activity should impinge on larger buoyancy peaking near the
   south-central NE/north-central KS border, which in conjunction with
   strengthening low to mid-level flow attendant to the aforementioned
   shortwave trough, should foster an intensifying and broadening MCS.
   All severe weather hazards will be possible, but destructive wind
   gusts may ultimately become the more widespread hazard across
   south-central to eastern NE and north-central/northeast KS. This
   activity should generally weaken east of the Mid-MO Valley later
   this evening.

   Intense surface heating into the 90s to the west of the dryline
   should lead to minimal MLCIN by late afternoon along the dryline. A
   few discrete supercells are possible across the central to
   south-central KS and north-central OK portion of the dryline where
   mid-level height falls will occur. Farther south, confidence
   decreases in sustained supercell development, but conditionally the
   threat will exist to the Red River. If sustained supercells form,
   very large hail along with tornadoes will be the primary hazards
   amid 62-65 F surface dew points. While the corridor of minimal MLCIN
   may be narrow given the strength of the elevated mixed-layer
   relative to warm-sector moisture quality, any established supercells
   will encounter an intensifying low-level jet this evening. This
   could support a couple strong tornadic supercells as well. More
   probable convective development is anticipated later in the evening
   as the sweeping cold front overtakes the dryline from north to
   south. Convective mode will be linear within this regime, but an
   eastward-propagating MCS is possible with damaging winds becoming
   the more common hazard. This activity should tend to weaken
   overnight as instability diminishes over the Ozark Plateau.

   ..Grams/Mosier.. 04/29/2022

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