Juneau is scheduled to get soaked this weekend. The National Weather Service office says they expect the area to get 2.5 inches of rain on average across the Juneau area, so they’re calling for 1 to 3 inches.
“One part of town might get the 1 inch and another part of town might get the 3 inches,” said forecaster Nicole Ferrin. “That’s pretty standard to see a variety across the area.”
The system will come in two waves. Heavy rain will fall Friday night, but then there should be a break with lighter rain early on Saturday morning before picking up again on Saturday afternoon.
The storm is expected to move out on Saturday night.
But that doesn’t mean the forecast for the Ironman Alaska race on Sunday will be high and dry. The forecast is for off-and-on showers, with the heaviest showers coming in the morning.
“We often see some breaks form over Lynn Canal,” said Ferrin. “So perhaps the end of the road could see some sunny breaks in the afternoon, moreso than, say, the back of the valley.”
This weekend’s rain event is the result of an atmospheric river — a long, fat column of moisture aloft that looks a lot like a river in satellite imagery. It hitches a ride on the jet stream, which directs it right at Southeast Alaska.
Local rivers and streams will rise with the heavy rain, but Ferrin says we’re fortunate that we had a break from the rain for a few days ahead of this storm.
“A lot of our rivers and lakes were able to fall over the past two days,” she said.
Most of the time when Juneau sees flooding, the days before are really wet and the ground is already saturated. So, Ferrin says rivers could approach bank-full this weekend but aren’t likely to flood.
Temperatures will be in the mid to upper 50s on Saturday and Sunday. By Tuesday, Juneau might see some sun again.