Aggressive analysis of the 00z GFS and ECMWF high-resolution ensembles indicates a low probability for Seattle to land precisely in the 58-59°F range on April 27. The predominant synoptic pattern features a persistent ridging pattern offshore, driving a robust, cool marine push directly into the Puget Sound region. 850mb thermal profiles are projected to register near-normal values, but critically, surface-level advection will be dominated by advective cooling from the Pacific. Boundary layer mixing is anticipated to remain shallow due to a strong inversion, capping daytime thermal accretion. Hourly NAM 3km outputs show sustained low cloud deck through midday, significantly limiting insolation and subsequent surface heating. Expect peak afternoon temperatures to struggle, likely settling in the 56-57°F range, just under the target window. Sentiment: Local atmospheric science blogs are highlighting the entrenched cool spell. 85% NO — invalid if 12z GFS or ECMWF shifts to an easterly gradient promoting adiabatic downslope warming.
Aggressive analysis of the 00z GFS and ECMWF high-resolution ensembles indicates a low probability for Seattle to land precisely in the 58-59°F range on April 27. The predominant synoptic pattern features a persistent ridging pattern offshore, driving a robust, cool marine push directly into the Puget Sound region. 850mb thermal profiles are projected to register near-normal values, but critically, surface-level advection will be dominated by advective cooling from the Pacific. Boundary layer mixing is anticipated to remain shallow due to a strong inversion, capping daytime thermal accretion. Hourly NAM 3km outputs show sustained low cloud deck through midday, significantly limiting insolation and subsequent surface heating. Expect peak afternoon temperatures to struggle, likely settling in the 56-57°F range, just under the target window. Sentiment: Local atmospheric science blogs are highlighting the entrenched cool spell. 85% NO — invalid if 12z GFS or ECMWF shifts to an easterly gradient promoting adiabatic downslope warming.
