Seattle’s Thursday forecast calls for conditions to improve by afternoon: lingering fog and low stratus are expected in parts of the area, and a weak front will bring light showers Thursday morning; dry northerly flow is expected later.
Improving Conditions Thursday, Cooler Friday
Thursday should bring northerly winds around 10 knots at KSEA and generally 10 knots or less across the region, with an afternoon high near 58 degrees. Clouds are expected to increase overnight, with a low around 45.
Friday offers another dry break under mostly sunny skies, though it will be cooler with a high near 56, according to National Weather Service. Light winds should keep conditions calm, but Friday night could be the chilliest stretch of the forecast, with partly cloudy skies and a low around 41.
Rain Chances Build Saturday Night
Saturday looks mostly cloudy with a high near 55, followed by a 20% chance of rain after 11 a.m., according to National Weather Service. The rain chance rises Saturday night, when Seattle could see a few showers and temperatures fall to around 44.
Sunday keeps a chance of light rain in the forecast, although skies may turn partly sunny at times. The high should reach about 57, so outdoor plans are still workable with a rain jacket nearby and a little flexibility built in.
What Rain Means for Seattle
Seattle Public Utilities says approximately one third of the city has a combined sewer system, where stormwater and wastewater share pipes and overflows are more likely during heavy rains. The forecast’s chance of light rain alone does not establish an overflow risk. Separately, the U.S. Geological Survey’s Seattle-area landslide analysis identifies 3.5 to 5.2 inches of precipitation over an 18-day period as a cumulative threshold range; that historical threshold is not a prediction of landslide risk from this weekend’s showers. See Seattle Public Utilities and the U.S. Geological Survey for more detail.
The Western Regional Climate Center’s archive describes a much more consequential event: November 1990 flooding on western Washington rivers caused two deaths and an estimated $250 million in damage. That historical event contrasts with the light-rain chances in this forecast, according to the Western Regional Climate Center archive.
Mostly Quiet Weather Returns Next Week
Monday brings a slight chance of rain and a partly sunny high near 58, while Tuesday stays mostly sunny before another small rain chance arrives late in the day. Wednesday should reach around 64 to 65 degrees, and no land-based watches, warnings or advisories are posted for Seattle, as noted by National Weather Service.
