MARSHALL — Hot temperatures are in the forecast for southwest Minnesota starting this weekend – and with them, there’s also increased risk for fires, according to the National Weather Service office in Sioux Falls.

“You’ll need to be extremely careful with anything that’s going to create a spark,” said meteorologist Jeff Chapman. People going outdoors or taking part in this weekend’s fishing opener should use caution, he said.

The region will be under a fire weather watch from 11 a.m. to 9 p.m. on Sunday, the NWS said Friday. The NWS said starting Sunday there will be potential for several days of critical or near-critical fire weather conditions, including afternoon temperatures rising into the 90s, low humidity, and wind gusts as high as 35 to 45 miles per hour.

How severe the fire danger will be will vary around the region, the NWS said. “The variability is going to be because of the difference in the grasses right now,” Chapman said. In some parts of the region, grass and vegetation have already greened up, while in other places they’re still dry.

The biggest threat of fire danger would be on Sunday through Tuesday, the NWS said.

Chapman said the region has been in a blocked weather pattern. “There’s a strong ridge of high pressure over the central part of the country,” and it hasn’t changed much, Chapman said. The high pressure brings weather conditions like warm temperatures.

Daytime high temperatures are forecast to reach 90 degrees in Marshall on Sunday, and stay in the high 80s and low 90s in the early part of next week. Other factors like increased wind will also allow overnight temperatures to stay warmer, Chapman said.

Chapman said there is a chance for some change in the weather, including precipitation and cooler temperatures, starting around Wednesday and Thursday.

Chapman said the 90-degree heat isn’t unprecedented at this time of year, but it’s not common. Marshall’s record for earliest 90-degree day was April 18, 1985. At one point or another in history, almost every date in May had also recorded 90-degree temperatures, he said. “It certainly doesn’t happen every year,” Chapman said.