When the latest models and forecast were released for Hurricane Hilary on Friday morning, Idaho found itself in a position it’s never been in before.

Inside the cone of uncertainty.

The National Hurricane Center didn’t start creating cones of uncertainty until 2002, but it’s already a rare instance for the west coast to be impacted by a hurricane.

The cone of uncertainty is the probable track of a named storm from its current position to its evolution into a tropical depression and eventual end.

Hurricane Hilary became a Category 4 hurricane off of Mexican’s west coast on Friday morning. A hurricane of that strength requires sustained wind speeds of 130-156 mph.

The hurricane is on a path to make landfall in the Mexican state of Baja California on Sunday before weakening into a tropical storm as it moves into California. It could drop up to 10 inches of rain in Southern California before weakening into a tropical depression and heading north.

That’s where Idaho comes into play. The cone of uncertainty has the remnants of Hilary moving into Southwest Idaho, while forecast models show the bulk of the storm’s remaining moisture hitting Boise head-on.

️The remnants of #HurricaneHilary have the potential to move over the region late this weekend into next week bringing significant rains and flash flooding to southwest Idaho and southeast Oregon. #idwx #orwx pic.twitter.com/hrmwaOL2Gc — NWS Boise (@NWSBoise) August 18, 2023

According to records at the National Weather Service in Boise, it’s the first time that Idaho has ever been included in a cone of uncertainty.

But there are a few caveats. The National Hurricane Center is responsible for the cone of uncertainty forecast, and the organization didn’t start creating them until July 2002.

“And since then, there’s only been Hurricane Kay last year which approached the Southwest U.S.,” Weather Service meteorologist Spencer Tangen told the Idaho Statesman.

Hurricane Kay approached the California coast before steering westward; it never made landfall. Hilary will be the first hurricane or tropical storm to make landfall in California since an unnamed storm hit the coast in 1939.

It won’t be the first time that the remnants of a hurricane impact Idaho, but it’s rare.

In 1976 Hurricane Kathleen made a path toward the West Coast, but by the time it reached California, it was a tropical depression — the final stage of a storm before it fizzles out. The remnants reached Idaho and, even in weakened form, brought 1.74 inches of rain to Boise, including 1.1 inches in a single hour.

The remnants of Hurricane Hilary will move into our area Sunday through Tuesday. Heavy rain could lead to localized flash flooding. On September 11-12 1976, remnants from Hurricane Kathleen brought some of Boise's heaviest observed rain: 1.74" total, 1.10" in 1 hour. #IDwx #ORwx pic.twitter.com/szaNp5Ocbb — NWS Boise (@NWSBoise) August 18, 2023

Early predictions from the Weather Service have Boise receiving up to an inch of rain from Sunday to Tuesday, while areas higher in the mountains, such as McCall, could get up to 1.8 inches. The Weather Prediction Center gives Southwest Idaho and surrounding mountains a 15% chance of exceeding flash flood guidance, which is when small rivers break their banks.