Seattle weather: Damp start to Halloween, drying out for trick-or-treating

While the day started quite rainy, most backyards will be dry for trick-or-treating!

There will be a few exceptions. For example, north King County and Snohomish County could have a convergence zone this afternoon and tonight, triggering some lowland rain and light mountain snow. However, it looks like our Halloween will be more of a treat than a trick!

Make sure the kids dress warmly for going door-to-door tonight! If you live in King and Snohomish Counties, I'd bring an umbrella just in case a shower pops up.

Here's a look at our evening forecast by microclimates! Upper 40s are on tap around 7 p.m. Along the far Washington coast, there could be isolated showers. 

Check out Futurecast below! The chance for showers drops dramatically this afternoon and evening. Tuesday through Thursday, only spotty showers are expected. 

Let's talk about the potential for flooding. Already, there's a Flood Warning in effect for the Skokomish River in Mason County. Minor flooding is in the immediate forecast there.

Over the Central Cascades, there's a Flash Flood Watch in effect through tonight for the Bolt Creek burn scar. If heavy rain moves over that area, flooding could be dangerous. Debris flows are also possible. Stay tuned!

For the Snoqualmie river near Carnation and Snoqualmie Falls, we expect water levels to reach "action stage" tonight (which is right below flood stage, per criteria from the National Weather Service). Here's a look at a hydrograph from earlier this morning: 

You can view river forecasts and observations on the National Weather Service website.

There's a slight chance for overnight thunderstorms along the offshore waters. A few more thunderstorms could bubble up Tuesday, but the lightning risk is quite small. Otherwise, you can expect mostly cloudy skies tomorrow. 

Wednesday and Thursday look quiet overall. There could be slight, passing showers at times, but the days will trend drier. Both mornings will be chilly; overnight temperatures will plunge to the mid 30s Thursday in Seattle. Some outlying areas and the South Sound could see have temps flirting with the freezing mark!

Friday will be our next "atmospheric river" event where heavy rain and winds are possible. Into Saturday and Sunday, temperatures drop. There could be at least several inches of snow stacking up over the passes this weekend. We'll track that closely as the time draws near!

Stay cozy today and enjoy Halloween with your family!

Take care, 

Meteorologist Abby Acone

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