Is September Usually this Wet?

The first seven days of September have been unusually cool and wet. Typically the warm dry summer weather extends until at least the Labor Day weekend, and often longer. But not this year. Fall came on suddenly. But will it last all month?  It’s safe to say that we’re done with the 90s for the summer, but we might still eke out a few 80s. 

First, here’s a graph showing the first week of September rainfall at Spokane going back to 1881. Yes, this has been wetter than recent Septembers. But historically, the first seven days of this month have been a lot wetter over the years. 


The culprit?  Could be El Niño. Could be tropical cyclone Lala. We’ll never know.  Here’s the weather map for last Friday. That’s an impressively large, cold low over the western US. 


By Wednesday of this week, the low will be gone and high pressure will make a brief appearance. But there a storm up in western Canada, just east of Alaska, waiting to drop into our area. 



This next storm will arrive by Friday and hang out here for the weekend.  It won’t be quite as impressive as what we’ve just seen, but still wet nonetheless. 



After that storm exits, we should be looking at drier weather for the middle of the month.  But low pressure is lurking just off shore. 



So what the rest of the month?  The European climate model expects the month to end on a drier and warmer note. Here’s the forecasts from that model for the last week of September.  The first map shows drier than normal conditions, while the second map shows warmer than normal. 






Here’s a summary of the rain chances for the next 10 days. 








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