Atmospheric river rolling across region

Second series of storms expected to bring snow later this week

COEUR d’ALENE — The weather phenomenon that has been sending a persistent pipeline of precipitation across North Idaho for most of the week is showing signs of letting up, but more storms are on the way. Meteorologist Randy Mann said we are currently experiencing an atmospheric river, a term many meterologists use to describe a series of storms that carry massive amounts of water vapor with them.

“Atmospheric rivers are relatively long, narrow regions in the atmosphere — like rivers in the sky — that transport most of the water vapor outside of the tropics,” states the National Oceanic and Atmospheric Administration’s website, www.noaa.gov. “These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.”

According to the National Weather Service, more than a dozen locations from Northern California into the Pacific Northwest have reported a foot or more of total rainfall so far this month, as of Thursday evening. Much of that has fallen over the last six days alone. Parts of coastal northwest Washington have seen 8 to 14 inches, while interior locations have seen 3 to 6 inches since last weekend.

Mann said another series of storms are coming, but they will track mainly south of the Coeur d’Alene region.

“We will still get some snow from that toward the end of the week,” he said. Mann said the next system of storms will likely alternate between snow and rain.

“But again, most of the storms will stay to the south, and we are going to get the leftovers,” Mann said.

A snowy, wet forecast is good news for Kootenai County, where the federal Department of Agriculture’s U.S. Drought Monitor continues to record extreme drought conditions. Throughout the rest of the Panhandle, conditions have improved since September, when the entire region’s drought classification was extreme.

But it’s going to take a lot more moisture and mountain snow to make a significant impact overall.

The National Weather Service’s drought outlook calls for drought conditions throughout Idaho until at least February.

Atmospheric rivers could help, since according to NOAA, 30 to 50 percent of the average annual precipitation in the west coast states occurs in just a few of these weather events.