The financial system remains relatively stable, thanks in part to the central bank’s March efforts, which traders and strategists say kept key bond markets functioning. As a result, credit can continue flowing to businesses and households in need of cash. That’s an important advantage over 2008, when a banking crisis helped to tip off the longest and worst downturn since the Great Depression.

But the economy is a system with many moving parts, so the trajectory and timing of a recovery are unknowable.

Consumers, for example, fuel about 70 percent of the economy. Many have either gone without a paycheck for all or part of the quarantine period or know someone who has. If that makes them more skittish about spending, they could hamstring a recovery.

States are another case in point. After the last recession, state and local budget shortfalls led to public sector layoffs that slowed an already weak crawl back to prosperity. This time, governments have taken an intense hit, threatening again to hold back an economic rebound.

The Fed is setting up emergency programs to help with short-term problems, allowing companies and governments to fund operations more easily.

Officials have been rolling out lending facilities, backed by $454 billion that Congress deposited at the Treasury. One program will buy debt from states, cities and counties, most of it highly rated, helping local governments to meet their cash needs. Two other programs will buy corporate debt, and the promise that they are coming has helped big companies in the credit markets.

Mr. Powell could use his news conference to hash out what comes next for the emergency lending programs. The central bank has earmarked less than half of the funding Congress gave the Treasury to protect against credit losses, so there is plenty left. Many programs are not yet operating.