Anchorage's first heavy snowfall of the season began Monday morning, putting the city under a winter weather advisory for 4 to 9 inches of snow through Tuesday afternoon.

The National Weather Service warning is in effect until Tuesday at 1 p.m. Drivers are said to expect slippery road conditions as a band of heavy snow forms west of Anchorage across Cook Inlet.

“This will initially favor Anchorage from north to west, where there is heavier snow,” meteorologists wrote. “The band will move eastward overnight into Tuesday morning, bringing a period of heavier snow to the entire Anchorage area.”

A winter storm warning for Wasilla, Palmer and much of the Mat-Su is in effect until 10 a.m. Tuesday. It's calling for 6 to 12 inches of snow from Wasilla west to Houston and Big Lake, also warning travel could be very dangerous.

As of midday Monday, Anchorage police spokeswoman Shelly Wozniak said city police had not received any significant reports of snow-related traffic delays. The agency posted a video online urging drivers to clear snow from windshields, headlights and taillights and to reduce speed before driving.

NWS meteorologist Kenna Mitchell said Monday that the storm was the product of two low pressure systems over northwest Alaska and Kodiak. Snowfall is also expected to impact the west coast of the Kenai Peninsula, including Kenai and Nikiski.

In Anchorage, Mitchell said the first band of snow will fall on areas near the airport and also cover higher elevations such as the Anchorage Hillside as it moves east.

“It's really like central Anchorage will most likely get less snow than the east and west, but not much,” she said.

It was not immediately clear Monday whether the snow will fall as fine powder or heavier, wet snow, possibly generated by warm air from the Kodiak system.

“There is uncertainty at the moment as to how far north the warm air can penetrate,” said Mitchell.

The forecast calls for 4 to 13 inches of snow to fall at higher elevations on the Seward Highway, such as Moose Pass and Summit Lake, during the storm.

Mitchell said snowfall is expected to taper off Tuesday afternoon in Anchorage but will continue in areas such as the Copper River Basin and Thompson Pass. Local weather should be relatively clear until Thursday, when more snow is possible.