November 27, 2021

Forecast: November 27th, 2021

By Conor Finneran

With only a few days left until December, Seattle is approaching a new all-time seasonal weather record…

After racking up 3.02 inches of rain in September, 5.76 inches in October, and 9.48 inches so far this November, 2021 is less than half an inch away from eclipsing 2006’s record wet fall and becoming the year with the wettest meteorological fall on record for the city. As of this hour, 18.26 inches of rain has fallen in the city since September 1st, already making it the second wettest fall on record. During 2006, 18.61 inches of rain fell in the same period, with 15.63 inches of that total falling just in November, which made it the wettest of any month ever in the city. Our monthly total for November won’t even be close to 2006’s, but its already the wettest November since then, and it’s looking very likely we’ll reach double digit precipitation before the month ends.

So how much more rain is coming?

Light to moderate rain is currently moving through the area with little signs of stopping at this hour. This rain will continue through the evening possibly becoming a bit steadier and heavier than it is right now at times. Rain should taper off around Midnight, but before then its definitely possible we pick up the 0.35 inch of rain we need to break the fall precipitation record.

In case we don’t break the record tonight, never fear, more rain will be here! Showers will be in the area all day Sunday, with the highest chance for steady rain being in the late afternoon hours of the day. Steadier rain will move in sometime during the middle of the day Monday, which will have the potential to drop some more measurable amounts. As for Tuesday, some measurable rain is definitely looking likely, however impressive amounts aren’t looking too likely at this time. With all this precipitation to come, expect between 0.75 and 1.5 of inches to be added to the monthly total before Wednesday.

A flood watch remains in place for Seattle until Monday morning as runoff from excessive rain threatens to overflow rivers and streams.

This fall has surely been exceptionally wet, but we still have several more months in the wet season. December is on average the third wettest month of the year, with an average monthly precipitation total of  5.72 inches. The Weather Prediction Center is forecasting a greater probability that December is wetter than normal, but only slightly, and equal chances of December being colder or warmer than normal.

Reach forecaster Conor Finneran at theuwdawgcast@uw.edu, or on Twitter @conweather