Rain, strong winds forecast for Southcentral Alaska through Thursday

A storm system will send "multiple waves of rain" and high winds across Southcentral Alaska starting overnight Tuesday, according to the National Weather Service.

Heavy rains are forecast to begin late Tuesday, causing rises in rivers and streams – with some of the highest expected in the Susitna Valley.

A special weather statement on the event, issued early Tuesday, covers an area extending from Cantwell south through the Mat-Su, Anchorage and all of the Kenai Peninsula to Kodiak Island. The affected region extends from Chignik in the west to Cordova in the east.

"The heaviest rain will fall over the northern and eastern parts of the Susitna and Matanuska valleys, East Anchorage and the Hillside, and areas of the Kenai Peninsula," meteorologists wrote. "For the entire event, some locations will receive upwards of 1 inch of rain."

Bob Clay, a meteorologist with the Weather Service's Anchorage office, said the incoming wetness was being driven by a cold front over the Bering Sea, which is causing winds from the southwest.

"It's rain right now over the coastal areas of Southcentral Alaska, and that southwesterly push is going to continue to push rain at us into tomorrow," Clay said.

Several areas will see "gusty southeasterly winds" associated with the front as it approaches Southcentral, including the Anchorage Hillside and Turnagain Arm, the Knik River basin and the Copper River valley.

As the system moves east into the Copper River area Thursday, Clay said, the rainfall will diminish to showers and give way to colder temperatures. According to the statement, that could bring some snowfall to elevations between 3,000 and 4,000 feet on Wednesday – and as low as 1,500 feet on Thursday.

"We're not expecting any significant snow, because most of the moisture that's associated with this front will have already moved by us," Clay said. "At higher elevations, you might see some snow mixed in with the cold air."

Although 2017 precipitation in Anchorage has been 1.37 inches above average so far, Clay said most of that was due to heavy winter snowfall. From March 1 onward, Anchorage has gotten 0.6 inches of rain – just 0.12 inches above its average of 0.48 inches for this part of the year.

"We've been running pretty much normal since March 1," Clay said.