HELENA — The continuing warm, dry conditions that have already extended the fire season are expected to last through the winter, which could intensify and expand the drought in Montana, officials said Thursday.

In Northwest Montana, the National Weather Service’s official rain gauge at Glacier International Airport has registered only 7.74 inches of precipitation this year, compared to an average 13.4 inches. Following its driest summer on record, the valley has received just half of its normal precipitation so far this fall, with 0.89 inches compared with an average 1.79 inches by Oct. 14.

An El Nino weather system is strengthening and may not weaken until spring, increasing the likelihood of warmer winter temperatures and drier conditions, Gina Loss of the Weather Service told the Governor’s Drought and Water Supply Advisory Committee.

The means the current drought is likely to persist or intensify in Western Montana and expand to more of central Montana, Loss said.

The state’s most recent moisture and water supply map shows severe drought in 13 western and central Montana counties and moderately dry conditions in nine others, despite some much-needed precipitation in September.

Harold Gemmell of the Northern Rockies Coordination Center said the conditions have extended the fire season, and many seasonal firefighters have already departed for the year. “Some of our large fires are still giving us some problems,” he said.

The current fire danger is low to moderate, and most of the fires starting now are human-caused, Gemmell said. He expects more fires with hunting season getting underway, Gemmell said.

The dry conditions have resulted in a very low surface water supply and low soil moisture, said hydrologist Eric Larson of the federal Natural Resources Conservation Service.

In the western half of the state, the stream flows were good last fall and winter, but they peaked early and then fell to below average, where they have since stayed, said Wayne Berkas of the U.S. Geological Survey.

That has led to below-average amounts of water flowing into many of the state’s reservoirs, Stephanie Micek of the U.S. Bureau of Reclamation said.

Spring wheat and winter wheat harvest and production this year were down due mainly to the dryness, said Eric Sommer, a U.S. Department of Agriculture statistician.

However, the harvesting of most crops is nearing completion, and winter wheat seeding so far is ahead of the five-year average, he said.