The first weekend of fall in Colorado could be cool, wet and snowy in some areas.

A low-pressure system bringing moisture from the Gulf of California is forming over the desert southwest and moving toward the state, said David Barjenbruch, a meteorologist with the National Weather Service in Boulder.

If the storm maintains its path, moist air will rise as it approaches the Colorado mountains. The result of these updrafts, Barjenbruch said, could be heavy rain and snowfall in parts of the high country on Saturday and Sunday.

“It looks like the chance for significant precipitation is pretty high,” he said. “It’s going to behave like a winter storm. We’re definitely going to see some snow accumulations.”

The heaviest snowfall will likely fall on the eastern slopes of the Front Range. Rain will likely fall in the rest of the Interstate 25 corridor and the Eastern Plains, he said. That could simultaneously provide relief for drought-stricken regions of Colorado, make roads slick at higher elevations and encourage dangerous flash floods and landslides in wildfire burn scars, the service said.

Several inches of rain and snow could fall in some areas, but Barjenbruch said the forecast was subject to significant uncertainty that would likely persist until shortly before the storm arrives.

The biggest unknowns are the amount of moisture in the Gulf, where the storm will make landfall and how fast it will move – all factors that could make the difference between missing much-needed moisture and devastating flooding from the heaviest rainfall event in months.

“There is potential for large fluctuations in the actual amount of precipitation,” he said.