September 01, 2026

The Fall Transition Has Begun

 One of the most remarkable aspects of Northwest climate is the rapid fall transition from summerlike conditions to cold and wet between September 1 and November 1.

This is illustrated by the average temperatures at Seattle (below).  

The current temperature forecasts are close to climatology, with no more 90s or 80s.

Climatological precipitation is on a very steep incline up (probability of measurable precipitation is shown below).  By November 1, we are about as wet as we get.


A wet weather system is now right off our coast and will move in tonight and tomorrow (see infrared satellite image for this evening).  Does not look like a summer pattern!



Rain totals through Thursday morning (shown below) will be significant.  Importantly,  precipitation will extend over eastern Washington, where some fires are still smoldering.

The official NOAA 6-10 day forecasts are for cooler-than-normal and wetter-than-normal conditions over the West Coast:


The timing of this cool/wet weather is perfect to facilitate an early end to the serious wildfire season.

10 comments:

  1. I rarely wake up grumpy on these longer nights, most times I just let her sleep

    ReplyDelete
  2. Yeah, this is the type of fall I remember as a kid. School starts and it rains and rains. Of course it is more varied than that. Some years it rains heavily, some years the sunny weather lasts until October, even if it is cooler. This has a huge impact on fires. The Bolt Creek Fire didn't start until September 9th. A lot of years it would have been out in a hurry (if it even started). But that was a dry September that never seemed to end. This looks like the opposite. The fires started a bit early this year but will end a bit early as well.

    ReplyDelete
    Replies
    1. I remember school starting and then two weeks of Indian summer.

      Delete
    2. I first moved out here worked on the Guide Meridian between Bellingham and Lynden back when it was 2 lanes was not familiar with the weather., supervisor tells me "our summer is shot". . We're gonna have a sharp change now. didn't make sense to me. Sure enough the clouds rolled in. It started raining and didn't stop till June. That's not typical for the Midwest you'll get your week of sun despite being 20 below zero

      Delete
  3. Is the NE Olympic rain shadow getting larger over time?

    ReplyDelete
  4. This weather is fine, but I'd appreciate it a lot more if it was commonplace two months from now. We need good autumn weather to come at winter's expense, not summer.

    ReplyDelete
    Replies
    1. "I'd appreciate the climate here if it was like it is somewhere else."

      Delete
  5. Please consider covering how strong winds can blow as the fall weather transitions. That trees still with leaves are vulnerable to toppling over and evergreen firs remain so.

    ReplyDelete
  6. Time to be thinking about reseeding the lawn and planting some shrubs!

    ReplyDelete

Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

The Fall Transition Has Begun

 One of the most remarkable aspects of Northwest climate is the rapid fall transition from summerlike conditions to cold and wet between Sep...