Current ensemble guidance from ECMWF and GFS models indicates a transient ridge building into the Southwestern CONUS by mid-May, actively suppressing the marine layer across the LA basin. Surface advection patterns strongly suggest inland thermal buildup will easily propel maximum temperatures beyond the 72°F threshold at key reporting stations. Historical May 10th climatology for inland valleys reinforces this, with the 8-year average high trending +3°F above the coastal 70°F mark. This bullish signal on upper-level geopotential heights is robust. 85% YES — invalid if a persistent deep trough establishes west of CA.
Current ensemble guidance from ECMWF and GFS models indicates a transient ridge building into the Southwestern CONUS by mid-May, actively suppressing the marine layer across the LA basin. Surface advection patterns strongly suggest inland thermal buildup will easily propel maximum temperatures beyond the 72°F threshold at key reporting stations. Historical May 10th climatology for inland valleys reinforces this, with the 8-year average high trending +3°F above the coastal 70°F mark. This bullish signal on upper-level geopotential heights is robust. 85% YES — invalid if a persistent deep trough establishes west of CA.
