A scorcher; Portland hits 100 degrees for the 5th time this year

7:45pm Tuesday…

What a scorcher today! At the last moment (6pm) Portland International Airport made it to 100 degrees.

Notice Portland is slightly hotter than surrounding cities. But Scappoose and Troutdale (also official metro stations) did make it to 99. 100 degree temperatures reached through the Gorge too. Dodson, Bonneville, and east to The Dalles hit the century mark. The official Hood River station is up in the lower valley…a bit cooler than at river level. It’s also surprising that PDX made it to 100 with very light easterly (offshore) flow that never surfaced within the metro area.

This is the 5th time we hit 100 in Portland this summer. That has only happened 3 other times, most recently last year

Today is also the LATEST 100 degree reading since 1998. Hitting 100 at PDX is quite rare after mid-August. Back in 2016 we had two back to back days on the 19th and 20th. We haven’t seen a 100 degree day after August 20th since 1988

Yes, Portland DOES see more 100 degree days than in the past. Although up until these past two years the trend wasn’t as clear over the last 50 years. Yes, 100 degree temperatures were VERY rare from the 1800s through the 1920s. But then from the 1970s to 2020 they became more common, but seemed to have “leveled out”. But now in just these first two years of the 2020s we’ve picked up 10 days at/above 100.

This really puts the icing on the cake for the month of August. For many of us, this is the warmest/hottest August and/or month on record. That includes: Portland, Astoria, & Redmond. Salem will probably end up as #2 warmest month on record; those records go back to the late 1800s! It’s the 4th hottest month in Pendleton. Regardless of exact placement…it’s been a blazing hot August inland from the beaches

Alright, that’s a lot of numbers. What’s ahead? A slight cooldown the rest of this workweek, then mainly 80s for Labor Day weekend. A strong ridge of hot high pressure is centered just to our east

The ridge slips just slightly east tomorrow and Thursday, giving us just some slight marine air cooling. On Friday, an upper-level system slides by, “denting” the hot ridge. That COULD give us significant morning clouds either day and highs well down into the 80s.

Then the ridge pops up behind that system again for the big holiday weekend. Sunday’s forecast of 500mb heights shows hottest air is east of us, but it’s still warmer than normal

Finally, sometime early-mid next week the ridge should flatten a bit, pushing temperatures down to more normal values…70s or lower 80s

Still, this is generally a dry pattern. In fact as of today, the 56 consecutive days without measurable rain is the 4th longest streak on record in Portland.

Summary

• Tomorrow will not be as extreme as today…closer to 90 degrees in Portland metro area
• Temperatures remain above normal through the first few days of September
• There’s no sign of a soaking rain, or even cool/showery weather, in the next 10 days

That’s it for now, try to stay comfortable with a very warm night ahead!

Chief Meteorologist Mark Nelsen

A slow fire season so far, plus some “warm” Pacific Ocean water along the beaches

It’s been a hot August, with 6 days at/above 90 degrees in Portland so far. I expect at least two more 90 degree days tomorrow and Thursday before a late week cooldown.

Right now (on August 23rd), Portland, Astoria, & Redmond are not only experiencing the warmest August on record, but the warmest MONTH on record too.

(kptv)

This month (so far!) is beating out the all-time hot month of July 1985 in Portland. The entire Pacific Northwest has been quite warm.

(WeatherBELL)

Does it seem like it’s been quite awhile since we’ve seen a “cool” August? Sure enough, the last one was August 2010 in Portland. Not every August has been scorching hot, but a bunch of them HAVE been hot.

Now keep in mind that we still have 8 days to go this month. There have been many Augusts where cooler weather, clouds, and even showers have shown up in the last week of the month. I don’t think that’s going to be the situation this year, but we WILL see a brief cooldown this coming weekend. For now we’re under higher than normal upper-level heights = warm/hot weather

(kptv)

But by Saturday a couple of weak disturbances are moving down through SW Canada.

(kptv)

The result is LOTS of cool onshore flow Friday through Sunday leading to cooler days and cloud cover. I don’t think it’ll be a “gray weekend”, but plenty of morning clouds. There is a good chance we see a few sprinkles or areas of drizzle Saturday morning too. You can see about 1/2 of ECMWF model ensemble members give us at least a trace of rain Saturday.

(kptv)

Don’t stop watering…that’s the best we’re getting rain-wise in the next 10 days. It’s back to upper-level ridging early next week, this map is for the last day of August 2022…next Wednesday

(kptv)

FIRE SEASON OKAY SO FAR…

Are you surprised how quiet this fire season has been so far? Yes, lightning strikes have been a bit less frequent, but it’s amazing how quickly fires have been discovered and quickly brought under control across the region. Right now Oregon has 8 large fires burning, but none of them are “raging out of control”. The important number here is the last one…less than one square mile of Oregon has burned in the past 24 hours.

(kptv)

This graphic is about 5 days old, but it gives you the idea…we’re running well below normal for acreage burned as of mid/late August

(kptv)

I don’t see any big rounds of lightning in the next 8 days, and that takes us to the beginning of September! Fingers crossed…

WARMER THAN NORMAL OCEAN WATER

One last item…

If you’ve stepped into water along the far northern Oregon coastline or the Washington beaches, you’ve probably noticed it isn’t as ice cold as normal. You aren’t crazy. Take a look at the northern Pacific temperature anomaly chart. Almost the entire basin has warmer than normal surface water.

(kptv)

Now look at the actual temperatures (yellow is 60-70 degrees) and you see some 60s from about Manzanita north up onto the Washington coastline. The central and southern Oregon coastal waters ARE in the 50s (green)…more normal there.

(kptv)

I don’t have any great thoughts about WHY the water is running warmer than normal. Usually this is caused by the typical north/northwest wind along the coastline turning weaker than normal. But I haven’t noticed that this year. Regardless…should be something interesting to watch

That’s it for now…enjoy the cooler weekend!

A cool and wet spring has turned into a hot summer, more heat is on the way

It’s been almost two weeks since my last post. Summer vacation interfered a bit, plus we keep real busy around here lately…lots of newscasts! Not as much time for blogging during the warm season.

That brief heatwave around the 7th gave us another 100 degree day, then temperatures cooled and SOME of you had quite a thunderstorm on Tuesday evening the 9th. That was mainly down around Salem. The Portland metro area has avoided any sort of overnight lightning event this year. Even though technically we didn’t have 3 days at/above 90 last week, anytime we get well above 95 it’s considered a heatwave.

(kptv)

Our 4th heatwave arrived Monday and today we topped out at 98 degrees. That makes today our 20th day at/above 90 degrees this season

(kptv)

August temperatures are running well above normal now. What a string of warm/hot Augusts…we haven’t seen a cool August since 2010!

The culprit is upper-level heights consistently higher than normal since late June. Right now we’ve got a strong upper-level ridge centered over Idaho.

(kptv)

That ridging keeps the marine layer quite thin and right along the coastline. Strong ridging means nature’s air conditioning (cool ocean air flooding inland) shuts down. It appears this setup may continue through the end of August as well. Take a look at the 500 millibar pattern (lines) and anomaly (colors) the next 7 days. This is around 18,000′ overhead

(kptv)

Then the 8-15 day forecast (ECMWF ensemble average) looks similar

(kptv)

Head down to 5,000′, use the GEM (Canadian) model instead, and the temperature anomaly is there for that last week of the month.

(kptv)

This is going to go down as a very warm August…once again. Let’s just hope we can avoid a setup that could give us strong easterly wind for high fire danger, or lots of thunderstorms. As you probably suspect, this is a very dry pattern. Today was our 42nd day without rain…in 11 days we’ll break into the top 5. Keep watering!

(kptv)

Tonight we are seeing a southerly upper-level flow bringing cloud cover and a few light showers north. The cloud cover overnight following a hot day is the perfect setup for a very warm night. We may only drop to 70 degrees…yuck. Of course the all-time record was set last year during the historic late June heatwave.

(kptv)

These records can be tricky to achieve for two reasons; they are based on the calendar day AND on Standard Time. For example, if we only drop to 70 around sunrise Thursday, it must stay at/above 70 all the way until 1am Friday to have that number stay on the books for August 19th. A strong marine push tomorrow evening could drop us below 70 before that time. We will see!

Heat wave this weekend, plus shower/thunder chance west of Cascades

11pm Friday

It’s been a nice week with comfortable temperatures; much better than last week’s heatwave!

(kptv)

The heatwave this weekend will be shorter AND far drier. We won’t be seeing any of that humid weather, at least through Monday. This is what we’re thinking right now for temperatures

(kptv)

Notice we probably won’t break any record high temperatures. That’s because we’ve seen big heatwaves in early August (some very high records!) and we should just barely touch 100 on Sunday only. Skies remain totally sunny tomorrow and Sunday, then a few clouds show up Monday. There are also hints that a strong marine push of cooler air comes inland Monday morning. If that happens, it’ll cool the southern Willamette Valley first, with most cooling waiting until Monday evening in the Portland metro area. So it’s possible Albany and Eugene don’t make it to 90 on Monday. We will see. If we hit 100 on Sunday (again!), it’ll be the 3rd time this summer. Remember we hit that century mark FIVE TIMES last summer. It is unusual, even in our warming climate, to see so much 100 degree action. Just for fun, I looked at 100 degree days each decade in Portland. I used PDX airport records back to 1970, then downtown observations back into the late 1800s. The downtown records have lots of gaps the past 40 years. It’s obvious we have LOTS more 100 degree days than 120 years ago. A 100 degree day was extremely rare in Portland around 1900. But also notice not as many in the 1990s. It’s also interesting we’ve had (at least) 8 in just these past two years!

(kptv)

Cooling onshore flow begins later Monday as an upper-level low approaches the coastline.

(kptv)

This low will move north through the outer waters of the Pacific Northwest from Monday through Thursday. As that low passes by, we get quite a surge of moisture overhead, nice lifting, and southeasterly upper-level flow. This CAN be a perfect setup for thunderstorms west of the Cascades. We haven’t seen a good thunderstorm outbreak yet this summer along the I-5 corridor. This COULD be our chance. Of course each model is a bit different, but they all imply something interesting could happen at some point between Monday night and early Wednesday.

I’ll be down in southern Oregon next week on a final camping trip. Diamond Lake is calling! So no blog updates until at least the 15th.

The historic July 2022 heatwave has ended

9pm Monday…

What a terrible week to be without air conditioning in western Oregon or southwest Washington. I was off on vacation (Leavenworth WA & B.C.), and I can tell you it was hot everywhere in Cascadia…except along the coastal beaches.

Summary

• The last week of July 2022 will go down in history featuring one of our greatest heatwaves
• Portland, Seattle, Eugene, & Medford saw their hottest week on record, Salem, Pendleton, & Redmond 2nd hottest
• As expected, nighttime temperatures were record-breaking warm due to high humidity
• Humidity was quite high; one of the “sweatiest” heatwaves I’ve seen in our area

All the Stats

Today’s high in Portland was 89 degrees, our first day back in the 80s since Saturday the 23rd. You just endured the warmest/hottest week on record in Portland. Take any 7 days in Portland’s history, adding the 14 highs/lows, then divide by 14. You get the average temperature for those 7 days. The 83.4 you see below is the highest on record

(kptv)

This included a record 7 consecutive days at/above 95 degrees

(kptv)

Salem was worse, enduring 7 days at/above 98 degrees! In Portland is was NOT the longest spell of 90+ days though. That record is from 2009

(kptv)

We hit 100 degrees 3 times, peaking out at 102 on 2 separate days. Note no “extreme” hot days (103 or higher) this time around west of the Cascades. As expected ahead of the heatwave, a weak onshore flow was present most of the past week (except Tuesday). Believe it or not, that means we could have been quite a bit hotter.

(kptv)

In my view, the most stunning part of this heat wave is what happened overhead. The 850mb temperatures (in Celsius around 5,000′) on the Salem weather balloon soundings were record warm/hot. It peaked at 25.4 on Tuesday and Wednesday, 28.2 on Thursday, 26.8 on Friday, 27.0 Saturday, & 26.2 on Sunday. That Thursday number is higher than anything previously seen in either July or August (27.6 deg). So it’s fair to say this was the hottest overhead atmosphere we’ve seen in these two months. IF WE HAD SEEN OFFSHORE (EASTERLY) FLOW last week, temperatures would have peaked between 105-109. I think it’s especially interesting that the atmosphere got so hot considering 500 millibar maps were not shockingly warm. Highest heights were 590-595dm during that time.

East of the Cascades the hottest air DID surface Thursday, Friday, & Saturday. Take a look at the high of 112 at The Dalles and 109 at Redmond on Friday the 29th. If not for last year’s heatwave, those would have been all-time records. What’s the chance of setting all-time records in 2 consecutive years? It’s almost as if our climate is changing and warming (it is!).

(kptv)

Of course what made this heatwave really bad was the lack of overnight cooling and high relative humidity. Dewpoint is the best measure of moisture in the air we breath. It was regularly between 60-70 degrees, especially the 2nd half of the week through Saturday. There were plenty of spots in the hills with dewpoints at or even slightly above 70 (due to vegetation). The last time Portland dropped below 69 degrees was Thursday morning! I grew up and started my career with the mantra “you don’t need A.C. in Portland”. That’s no longer the case. Anyone in the urban area should have at least a room air conditioner for sleeping.

(kptv)

Finally, July ended up the 4th warmest month on record in Portland, only eclipsed by July 1985, 2015, & 2018. Those months were generally warmer across the entire month. Notice we were near normal until the heatwave arrived. This month just barely edged out August 2017.

(kptv)

That’s it for now. August is here and warm temperatures continue through the foreseeable future. A brief heatwave is possible Saturday through Monday with highs in the 90-95 degree range. Humidity should be LOW with that heat too. I see dewpoints mainly in the 50s.

Enjoy the cooldown through Friday!