Other than a couple heatwaves (2006/2009 heatwaves) and June 4 2009 t'storms, not really much I can say that were very memorable in the warm season when I lived west of the cascades until late 2010. While few in frequency we definitely can get heat that is deadly and t'storms that can impress.
06/04/2009 was the last time the lowlands had a warm core tornado, and warm based TOR warning. Nearly all tornadoes west of the cascades are cold cored, same goes for warnings issued that are based on cold core storms.
I remember hearing reports of people being hospitalized due to asthma attacks (and it's possible not all of them were asthmatic people). I recently read an article about a year back that there is a "thunderstorm asthma" that occurs around the world, although it's uncommon. I don't have asthma myself and there was a storm here in Klamath Falls on June 9th 2015, early in the morning during a frequent lightning event that gave me possible symptoms of this. This one literally had me nauseous every time I stepped outside to take a shot of the sunrise. The air had a "heavy" sensation to it. There was a combo of smells.. also keep in mind this was in the middle of a pretty decent heat wave for early June, which maybe could have contributed to this experience. I also think my high elevation over 4000 feet likely plays a role in exacerbating the environments interaction with the storm, air, ozone, particles, etc. There are explanations in detail how this occurs during storms or during approaching storms. Picture for a moment, upper 60's, sun coming up, lightning every 5-6 seconds from the south and west pretty nearby, and extremely thick/humid air. Then the nausea to add a touch to the experience. Because there was a storm this actually didn't bug me one bit. I weathered through it.
The other storm in 2009 didn't actually give me any symptoms but I definitely could notice heavy smells of pollen, bark/dirt, tree like smells. My brother who happens to have allergies, began sneezing and blowing his nose for about a half hour during the 2009 storm.
06/04/2009 was also the only time I have observed t'storms literally covering most of the entire forecast area. Even on the east sides of Oregon and Washington that sort of thing can be difficult to happen. I had looked back at older radar data from the 90's (back to when KRTX was built in 1995) and couldn't find any similar events like that. I'm sure the last time something this significant occurred was back in May 1993 in western Oregon.
Another thing not frequently mentioned is the longevity of the storms. It seemed like none of the cells really cycled/died, they kept going for hours. They began around 11:00am on KMAX and lasted until 5-6pm just north of the border of WA on KRTX. In terms of radar data available that is just about unheard of (but we do have many more years of radar data to see do we?).
And man, those shelf clouds. I do bring this up from time to time but that was the most exciting sky I've seen so far since I was born. I have now been east of the mountains for over 6 years and haven't seen a sky like it (yet). For those who may not have seen my pictures I can share them if requested. (though keep in mind slight edits were done. Had a cheap cam back then and accidentally had the photos on a low exposure setting... ugh..)
When I was younger I sort of remember August 1999 as being kind of a bigger storm than normal. Forgot the day. And there were multiple days in a row convection occurred that first week of August so I'd need to eyeball some radar data to be sure of my particular storm.. nonetheless that one and the Oct 2 1998 storm in Milwaukie were some better ones. (that one BTW took down a couple trees, and one tree landed on our fence. We were out of power until morning).
For the most part I had a somewhat higher standard set for storms than others who lived in the same area. If it's just a couple rumbles or a downpour it wouldn't really excite me. With that said, there have definitely been a few times west of the mountains that did surprise me and showed potential. The Cascades usually act as a barrier for opposite kinds of climates, except not for the short term, rather long term is the real boundary there.
Weather Data for Klamath Falls, OR
Snowfall (with % of seasonal average)
2010-2011 - 58.20" (161%)
2011-2012 - 49.00" (136%)
2012-2013 - 16.70" (46%)
2013-2014 - 9.05" (25%)
2014-2015 - 2.90" (8%)
2015-2016 - 54.45" (151%)
2016-2017 - 63.00" (175%)
2017-2018 - 18.10" (50%)
T'storm Days: 11 (2017), 12 (2016), 20 (2015), 21 (2014), 16 (2013), 2 (2012), 12 (2011) / 1980-2015 Avg = 12 T'storm Days
Severe T'storms: 4 (08/08/2017), (07/24/2017), (01/19/2016), (08/05/2012)
"Almost" Severe - (08/10/2017), (05/04/2016)
Vicinity Severe T'storms (close enough to hear, with official severe reports)
(07/09/2015), (07/05/2015), (06/09/2015), (08/05/2014), (08/04/2014), (08/22/2013), (08/12/2013), (09/12/2011), (09/04/2011)