Last Day Of September Brings Puget Sound Another Soaker: Forecast

SEATTLE — A unique weather band is settling over Western Washington, promising one more run of wet weather before October arrives. According to the National Weather Service, September's rain totals are already well above normal in Puget Sound, and the last day of the month is looking to run up the numbers.

Forecasters expect Wednesday's scattered showers will intensify through Thursday, bringing more widespread rain across the region. While meteorologists do not expect river flooding or other major impacts from the storm, the weather pattern itself — called a "baroclinic leaf" — is rather unusual. As the system nears, forecasters say it will take on more of a comma shape.

As for winds: The strongest gusts should pass by late Wednesday evening, but breezy conditions will stick around into Thursday. Since many trees still have foliage weighing them down, the high winds could make for a few headaches, including downed branches and power outages. Overnight gusts were forecast to peak at 25 mph around Seattle and as high as 50 mph further north around Bellingham.

By all accounts, Thursday is likely to be a soaker as moderate to heavy rain moves inland, bringing most Puget sound communities up to a half-inch of precipitation by 5 p.m. The coast and mountains will be even wetter.

After the storm passes and rain tapers off Thursday night, quieter weather is in store for the first few days of the month.

"High pressure over the [Pacific Northwest] will bring mild weather as we slide into October," NWS Seattle wrote Wednesday. "The flow will turn offshore and we'll see temperatures gradually warming and back into the mid 60s to lower 70s."

Rain is forecast to return before too long, with another frontal system due early next week and chances for precipitation building again by Monday or Tuesday.

Here is the 5-day weather outlook for the Seattle area:

• Thursday: 57°/51° (Rain - 100%)
• Friday: 62°/48° (Decreasing clouds)
• Saturday: 62°/51° (Mostly cloudy)
• Sunday: 64°/53° (Slight chance of rain)
• Monday: 64°/52° (Slight chance of rain)