A succession of Pacific storm systems is forecast to move across western Washington through the coming week, bringing sustained periods of rainfall to lowland areas and accumulating snow in the Cascades and Olympics.

Meteorologists say the pattern is being driven by a broad, moisture-laden flow from the Pacific Ocean, steering multiple frontal systems into the region in relatively quick succession.

While no single storm is expected to be extreme on its own, the cumulative effect of repeated rainfall could lead to saturated soils, ponding on roadways and rising river levels.

Lowland communities from the Puget Sound corridor to coastal areas are likely to experience steady rain at intervals, with occasional heavier bursts accompanying frontal passages.

In the mountains, colder air at higher elevations is expected to translate the moisture into fresh snowfall, improving snowpack but potentially complicating travel across mountain passes.

Transportation officials are advising drivers to monitor pass conditions closely, as fluctuating snow levels could result in periods of slush or compact snow on higher routes.

Emergency planners are also keeping watch on river basins that are historically prone to minor flooding during prolonged wet spells.

The unsettled pattern reflects a typical late-winter configuration in the Pacific Northwest, where successive systems track inland along the jet stream.

Forecasters indicate that conditions may remain changeable beyond the current outlook period, with additional disturbances possible before a more stable ridge of high pressure develops.

Residents are encouraged to stay updated through official weather advisories and to prepare for wet conditions, reduced visibility and winter travel impacts in mountainous terrain.