James Jones

I get the desire to counter Tim but I think this spring is more impressive than some are giving it credit for, at least since the second week of April. April was one of the wettest on record for the region, we had an unprecedented snow event even going back to the 1870s (maybe something similar happened before that? Justin would probably know) and it's been persistently below normal with only very brief interludes of warmer than normal. PDX hasn't gotten above 75 yet which I imagine is pretty rare by this point in this spring, though I don't have time to check at the moment. Overall it hasn't been historic aside from the snow event, but I think it's still been pretty impressive.

Yeah I'm worried about that too in Lake Oswego. I got completely owned in February 2021 but at least this time there's no freezing rain.

Looks like PDX has locked up its first sub 50 April high temp in a decade. Tomorrow's record low max of 50 should go down easily too.

Given the drought the West is facing it wouldn't surprise me if we had another Dust Bowl type summer out this way.

Are there any historical analogs for what the models are showing? The only significant April snowfall I'm aware of for the Portland area is 4/1/1936.

Yeah, before last June that was probably the most anomalous temperature event on record for the region. Numbers like the 21 degree high and 6 degree low at SeaTac, or the -1 reading in Olympia, would be top tier for any day of the year let alone in mid November. Seattle's 21 degree high on the 12th is actually earlier than Burlington, VT's earliest 21 degree high on record to add some perspective.

The trend has been going on for so long now that I think you have to assume there's more going on than just luck, but I have no idea what the mechanism could possibly be. At PDX February has been colder than January for 4 years in a row, which has never happened before in the period of record, and it seems like a decent bet that it could happen yet again this year. It's not like it's just been barely colder either, the last 4 years January has averaged 44.8 compared to 41.5 for February.

To me one of the most interesting aspects of this climate is how seasonal lag only really effects the warm season. Spring is very long around here with June actually being slightly cooler on average than September, while fall is very abbreviated compared to places east of the Rockies. Averages bottom out pretty much right on the solstice and start ticking up a couple tenths before New Years.

Hopefully this trough can clear the air and tamp down the fires a bit, though with another big ridge looking to build in on the backside any relief on the fire/smoke front would be temporary. At the very least it will be welcome to have a few days with coolish temps and some rain.

What mechanism is causing surface temps to overachieve so much? There's not much of a compressional element with this one. Low soil moisture plus very warm overnight lows?

1 in 30 is probably about right for most of the Puget Sound (depends of course on how close to the water the exact location is) but for the Willamette Valley 100+ has occurred in probably 50-60% of years since the mid 1920s. In PDX's 81 year period of record only 35 of those years went without a triple digit day, so 57% of years have hit 100. It's a different story before that though, from 1874 (the first year of records for downtown Portland) through 1903 there was a grand total of one 100+ day in that 30 year period. The warming in the last 90ish years has been mostly from a decline in the number of cool, troughy days, declining influence of the marine layer, and an increase in the number of days in the mid 80s to low-mid 90s. Though who knows, perhaps this year is an ominous warning sign of an increase in the number of days with extreme heat.

Hopefully some of that is falling over the Bootleg fire.

Junes 2010-2012 were fairly impressive and July 2011 was solidly cool, so I have hope that we could see something better than July 2016 again. Of course the longer we go without a legitimately cool summer month the less likely it is to happen again. August is a different story though. The last time we saw one that was below the 20th century average was back in 2000 and that was only by a couple tenths of a degree. Certainly possible we won't see another one with a sub 80 average high at PDX again in our lifetimes.

This isn't the case at all. The reason you have this impression is because the local station you like to use was seriously overexposed earlier in the 20th century. Summers in the second half of the 20th century were generally both warmer and sunnier than in the first half, and precip has shown essentially no trend going back to the late 1800s with the possible exception of the last decade or so (though that could easily just be a random blip like we saw in the mid 1920s through the early 30s). There's also fact that September trended much more summerlike over the course of the 20th century. Here are the average summer temps and precip for the Puget Sound and Willamette Valley

1977 might be the ultimate example of this. The first 17 days of the month was perhaps the hottest 17 day stretch on record, then we crashed into fall and never looked back. The last 10 days of the month had 3.59" of rain at SEA, 4.17" at OLM, and 3.26" at PDX. Even a pale imitation of that would be a godsend for our ecosystem.