February 5, 2026

Throughout a year-long planning effort, NOAA has been supporting public safety and emergency management committees across the San Francisco Bay Area. The Air Resources Laboratory worked with the National Weather Service’s Monterey Weather Forecast Office to set up hourly automatic HYSPLIT runs for key areas around the Bay Area in coordination with local safety response organizations.

HYSPLIT is an ARL model that can forecast the trajectory of airborne hazardous materials. Using meteorological data, the model computes the most likely path of travel from a starting point and can forecast concentrations of the airborne material and how it might settle to the ground along the way.

With a projected 90,000 people expected to travel to the Bay Area this weekend, HYSPLIT is a useful tool for emergency managers to understand where risks to public safety could be in the event of a chemical leak. ARL did the same thing for the 2025 FIFA Club World Cup games, where one of the hypothetical scenarios ARL modeled involved a small leak from a train car over eight hours at a station right next to the stadium. With hourly model runs, emergency planners can run different scenarios to make plans in the event of an actual incident.