A lot has happened in the weather world since I blogged last, both locally and nationally. Normally I like to relax in September because the weather is too “beautifully boring” to write about at length. But with multiple Category 5 hurricanes on the Gulf Coast and horrendous wildfires across the west? This has been the worst possible time for the WeatherTogether site to have accessibility problems (editor’s note: Karl and others have had problems accessing the site because our host is incorrectly blocking certain IP addresses. We have a ticket in to resolve this issue).

Anyway…the calendars say it starts tomorrow but Fall has definitely been here since at least last Sunday night. A very chilly upper-level trough – just about the coldest airmass we can get at this time of year – has been over us for most of the week, bringing showers and Mt. Hood snow as low as 5,000 feet. The airport in Dallesport reported 0.75″ of rain over the past 4 days and PDX got nearly 2″, with the strong storms from the Gulf of Alaska. But there were nearly 5″ of rain in parts of the Eagle Creek Fire zone! Good news because it means the fire is pretty much dead now.

Tuesday there was a minor tornado east of Lebanon in the Willamette Valley. Yesterday Wednesday, we somehow managed to get to 65 around noon, but much of the afternoon was spent in the low/mid 50s with wind and blowing rain! It definitely felt more like March or early April, than normal fall weather. But it’s perfectly normal for cold troughs in early fall to have some “spring-like” characteristics: blustery wind, downpours, hail/thunder, funnel clouds, and brief temperature spikes during sunbreaks.

With Summer 2017 long gone, how did it turn out? Pretty hot in the end, though not as bad as 2015. Certainly the FIRST HALF of the summer season (mid-June through most of July) was very mild compared to recent years. But I had this creeping feeling early on, that we wouldn’t get off the hook without at least one major heat event…and sure enough, the oven door opened right around July 31/August 1!

In the end we got 12 days at or above 100 degrees, though we probably would have had several more such days if “smoke cooling” hadn’t been such a big factor this season. Given how many smoky days we had in August…I bet our averaged high temps for the month would have been a full degree or more hotter, if we had somehow gotten the same hot airmasses without all the smoke. As it was, we had our 3rd hottest August on record at DLS and the hottest August since I was born. It was 4.9 degrees F above the 30-year average.

And it’s really too bad (for us unseasonable temp nerds) that the Eagle Creek Fire had to take a wee-wee on our September heat wave. Had we not lost 8-10 degrees due to smoke, temps would have been in the low to mid 100s for 5 or 6 days straight! That would have been worse than 2011 and historic for so late in the season.

This raises the question of whether increased smoke in the future (presumably due to climate change) might actually dampen some of the effects on our surface temps during the fire months of July-September. My guess is that it won’t be a big enough “negative feedback effect” to care much about. Sure… if every summer in the future was as smoky as the 2nd half of Summer 2017 in our region, then it might be worth noting. This was just a REALLY bad smoke year for our locality. Not all other locations across the West, suffered the same kind of smoke-induced heat reduction that we did in the Gorge.

In the short-term future…looks like a warm “Indian Summer” pattern sets in by the middle of next week. Temps should be back up into the 80s for at least one more time this season.

Looking ahead to winter…it now appears that a second La Nina is likely. Whether or not it will be stronger than last year is anyone’s guess, but the current models look pretty solid:

Let’s just hope we don’t have the same kind of perfect condition (snow-covered Columbia Basin & Gorge plus storms that kept veering south), that turned last winter into such a snowy mess. One per decade is plenty! The other pattern common in La Nina seasons, is cold valley rain coupled with very heavy mountain snow. Perhaps that’s the pattern that will dominate this year?