SPC 1200Z Day 1 Outlook
Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 1123 PM CST Mon Mar 08 2021 Valid 091200Z - 101200Z ...NO SEVERE THUNDERSTORM AREAS FORECAST... ...SUMMARY... A few thunderstorms are forecast mainly along the West Coast, while isolated activity cannot be ruled out over Iowa and neighboring states later tonight. ...West Coast... Weak mid-level height falls are expected across the western US as strong 500mb flow gradually sags south across southern CA/AZ. Very cold temperatures (-30C at 500mb or lower) will be noted north of the jet and steep, but cold, lapse rates will prove favorable for low-topped convection, especially in proximity to onshore flow off the Pacific Ocean. While much of the convection may struggle to produce lightning, as has been the case the last few days with this system, stronger updrafts will likely generate at least a few flashes. Low thunderstorm probabilities will reflect this threat, primarily near the Pacific Coast. ...Eastern NE/IA Region... Weak short-wave trough is forecast to eject northeast across the central Plains toward IA during the overnight hours. This should aid a LLJ that will increase across OK/KS/MO into southern IA by 10/06Z. While boundary-layer moisture return will be inadequate for surface-based buoyancy, forecast soundings suggest parcels lifted near 800-850mb may become uninhibited after midnight as LLJ strengthens. For these reasons it appears a few elevated thunderstorms may develop within the low-level warm advection zone. ..Darrow/Moore.. 03/09/2021
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