The National Weather Service warned Monday morning that heavy rains around the Anchorage area could lead to minor flooding in city streams.
A special weather statement was also issued warning of possible thunderstorms developing Monday afternoon in Southcentral Alaska, with the biggest impacts expected in Cook Inlet.
Early Monday, the NWS was already reporting heavy rain with ponding on roadways in Anchorage and the Matanuska Valley.
Meteorologist David Kochevar said 0.36 inches of rain was measured at Anchorage International Airport between 3 a.m. and 8 a.m.
"It's not unusual to see that much rain for Anchorage, but to have that come down in 5 hours is slightly unusual," he said.
Kochevar said to expect the worst of the rain through Monday morning, with it breaking up by the afternoon.
Meteorologists advised of possible flooding in Chester, Campbell and Ship creeks, with impacts expected from the Eagle River Nature Center to Joint Base Elmendorf-Richardson and Muldoon.
The flood advisory is in effect until 11:30 a.m. Tuesday.
The Weather Service also issued a special weather statement warning of thunderstorms beginning at 1 p.m. Monday for most of Southcentral, particularly in the waters of Cook Inlet.
"Mariners should be prepared for hazardous conditions today including strong and erratic winds, lightning and high seas," the NWS cautioned.
The heavy rain Monday, coupled with a pair of vehicle accidents on busy city thoroughfares during the morning commute, slowed traffic in Anchorage.
APD spokeswoman Anita Shell didn't know whether the accidents Monday morning were weather-related.
A single-vehicle crash on the Seward Highway at O'Malley Road closed most of the highway, leaving only one northbound lane open.
A second collision at Tudor Road and Piper Street slowed westbound traffic on Tudor.