SPC AC 041622

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1022 AM CST Fri Mar 04 2022

   Valid 041630Z - 051200Z

   ...NO SEVERE THUNDERSTORM AREAS FORECAST...

   ...SUMMARY...
   A few thunderstorms are possible today across portions of the West
   Coast, the Great Basin and into the central Rocky Mountains.
   Isolated thunderstorms are also expected late tonight across the
   central Plains and Upper Midwest.

   ...California...
   A few weak thunderstorms may develop and continue this morning ahead
   of a shortwave trough moving onshore across southern CA. While
   onshore flow appears modest, steep lapse rates and forced ascent
   beneath cold 500 mb temperatures will allow weak destabilization to
   continue. As the trough moves northeastward this afternoon,
   thunderstorms are expected to gradually weaken and diminish in
   coverage as buoyancy becomes more limited.  

   A few lightning strikes will also be possible later this afternoon
   and evening across the northern San Joaquin and southern Sacramento
   Valleys, ahead of a second shortwave trough approaching the
   northwest CA Coast this evening. Again, surface moisture will be
   limited in quantity, but cool temperatures aloft and dynamic lift
   ahead of the trough may support a few thunderstorms. 

   ...Four Corners and Rocky Mountains...
   As the southern-most shortwave ejects north and eastward through the
   afternoon and into this evening, lift will overspread much of the
   Great Basin and central Rockies. Cold temperatures beneath the core
   of the trough will allow weak destabilization despite relatively
   modest boundary-layer moisture. Isolated high-based thunderstorms
   will be possible late this afternoon and tonight. Some stronger
   surface wind gusts may also develop with this convection given the
   favorable thermodynamic profiles for evaporative cooling within
   stronger downdrafts. However, coverage and predictability of any
   organized severe threat appears to be below 5%. 

   ...Central Plains/Upper Midwest...
   The shortwave trough and associated upper jet are forecast to
   continue northeastward across the Rockies and move into the central
   Plains/Upper Midwest late this evening and early Saturday. The
   increase in lift with the passage of the trough/jet will intensify a
   weak lee cyclone across southwestern NE and northeast CO overnight.
   A nocturnal low-level jet is also forecast to develop, aiding
   southerly return flow and elevated moisture transport northward
   ahead of the deepening surface low. Steepening mid-level lapse rates
   ahead of the trough, combined with increasing moisture content will
   allow elevated parcels to destabilize across the Plains mainly after
   10 pm. A band of elevated convection appears likely to form from
   eastern NE and western IA in proximity to a frontal zone moving with
   the advancing the lee low. These storms should transit northeastward
   overnight with a low-end hail risk given the strong wind profiles
   aloft from the approaching upper-level jet. However, modest elevated
   buoyancy will be the primary limiting factor for greater severe
   potential, as the bulk of the deeper moisture appears poised to
   arrive after sunrise Saturday.

   ..Hart/Lyons.. 03/04/2022

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