PORTLAND, Ore. (KOIN) — Any Portlanders who intend to travel on a TriMet bus or train this weekend may have to plan ahead, as the transit service says the potential record-high temperatures could affect rides.

The National Weather Service issued an excessive heat watch for Northwest Oregon and Southwest Washington. Weather officials say the extreme heat will last from Saturday afternoon to Monday evening.

According to the KOIN 6 weather team, temperatures in the low 90s are on the forecast for all three days — and TriMet just announced that the MAX Green and Orange lines could be delayed once temperatures exceed 90 degrees.

“Over the past few years, TriMet has worked to reduce heat-related delays, and most of the system can handle temperatures nearing 100 degrees, thanks in part to improvements to our overhead wire and counterweight system,” TriMet said. “This prevents the wires from sagging as temperatures rise.”

Still, the Portland-area transit service encourages riders to monitor its service alerts in case there is a delay or disruption.

TriMet also advises passengers to give themselves extra time when traveling during peak temperatures, dress appropriately for the weather and stay hydrated — especially if their stop or station doesn’t provide plenty of shade.

The transit service says every train and bus in its fleet features air conditioning.