Dry October Start & Goodbye to Brian MacMillan!

5:30pm Thursday…

It’s been a bit wet at times today, but not exactly a big soaker. This wraps up the month of September AND the “water year”. We use “water years” because we want to put all of each wet season into one “bucket” for historical purposes. Since each wet season in our climate begins Oct/Nov and ends in April, meteorologists across the Western USA have created a “water year”…precipitation from October 1st to September 30th. We will end up with just over 30” this year; the number below will end up a bit higher after the showers today…

Notice we’ve had 4 dry years (lots of drought in Oregon) after two very wet years. Hopefully this winter we can get more rain/snow to recharge groundwater and fill reservoirs. More on that in a later post about the upcoming winter. It’s obvious we have a nice start to October. Both Friday and Saturday will be dry with warming temperatures. Anything above 70 is now considered warm…things change quickly this time of year.

But let’s get on to the big story…

Brian MacMillan is moving on…yes, Brian is leaving KPTV/KPDX here in Portland

After 12 years, my best “weather buddy” is leaving us. No, no one did or said anything offensive or illegal. He’s not getting fired, laid off, and probably won’t leave tire marks in the station lawn on the way out. Nothing like that. Brian has accepted a new position with…wait for it…FOX…13, not 12, in Seattle. I grew up in Chehalis, so I regularly watched Q-13 (KCPQ), just like Brian did since he grew up in the northern suburbs of Seattle. They are making some changes and one is the retirement of longtime morning weather anchor MJ McDermott. So Brian is taking over her morning shift in his “hometown”. It’s a great opportunity for him, but I’m really going to miss that guy!

Brian came here from Bend in 2009 with just a couple years of TV under his belt. Just a young guy with no obligations. During that time he got married, bought a house, and now has two kids. He’s blossomed into a solid meteorologist and reporter that we will miss. The old saying of “jack of all trades, master of none” doesn’t apply to him. He’s really good at just about everything and a solid professional. EVERYTIME I (or a boss) asked him to fill a role, he did it without complaining.

We just finished a brand new FOX12 WEATHER PODCAST (episode #30) and Brian talks about all the different roles/responsibilities he held here at KPTV. We had some great laughs as he went over 12 years of memories and crazy stories. I think this podcast is my favorite of dozens we’ve produced.

Find it on your Apple Podcasts or just go to this link: https://www.kptv.com/podcasts/weather/

One of my favorite memories is Brian (trying) to take a drink up at Women’s Forum viewpoint during a raging easterly wind…now THAT was good TV!

And he could have been a window washer! Luckily the ropes held for this story…

We were recording something at one point and BMAC just jumped at the chance to spray me down. We were aiming for that “sweaty” look, but putting diet coke in a some fancy wine glass just didn’t work out quite right…

And who fills out THIS MANY vacation requests all at once???

I once walked in to this pile of his requests; I left the pile and added the large red DENIED sign. We’ve had a lot of fun!

All those tornadoes? From Aumsville to Manzanita to Longview, we worked them together. I’m really going to miss Brian’s forecasting skills too. I’ll come in during a snow/ice event (or in the lead up to one) or we’ll have a conversation about the meteorology as we compare notes. We almost always have the same forecast, even in those tough winter weather setups.

And of course most of all I’ll miss Brian’s friendship here at work. We’ve shared the ups/downs of family life, (a couple) crazy coworkers, training new employees, conversations about COVID, riots, elections, deck staining, roof replacement, strawberry varieties, ties, suits, music, etc… You only see us for a few minutes at a time on TV, but remember we work together for 8 hours each day behind the scenes just like “regular” office folks. Brian is the nicest guy, always positive, and always asks his coworkers “how things are going”. I’ve learned a lot from him! Luckily, we’ll only be three hours apart via freeway…not too far away. Always time for a little Seattle vs. Portland gossip right?

So… to wrap it up, we’re losing a great employee but in a good way I suppose. New experiences are one of the best parts of life.

Good Luck Brian!

Chief Meteorologist Mark Nelsen

EF-0 Tornado Hits Battle Ground Monday

7pm Tuesday…

A couple times each year we get a (usually) weak tornado in our viewing area. That’s SW Washington down into NW Oregon and east into most of Eastern Oregon. They may be uncommon, but definitely not unusual.

Back in March a weak tornado touched down near the mouth of the Columbia River, close to Ilwaco. That was an EF-0. Last night a strong thunderstorm tracked through central Clark County. As it passed west of Battle Ground and then ENE to Yacolt, radar indicated some decent shear/rotation. The NWS issued a severe thunderstorm warning around 7:30pm, just as a tornado finished tracking through the area. Here’s the view at 7:35pm

Soon after I heard from Tyler Mode, an avid weather “geek” and photographer from Battle Ground. He was watching the storm and recorded video of a tornado passing just north of the city. Check out his video…especially around the 1:10 mark: https://www.tylermodemedia.com/Weather/92721-Tornado-Battle-Ground/i-tKsZzwz Pretty exciting! Listen closely for the roar in the distance.

Shorty after seeing Tyler’s video, we received a great view from Gary Gerber. This video really shows the circulation, wind in the trees, and debris in the air. It doesn’t get much better than that in our area.

Once we saw these two videos it was obvious a tornado had touched down. The Portland NWS went out and did a storm survey today. Surprise! It was ANOTHER EF-0. This is from the NWS report

Every tornado in our viewing area the past three years has been rated an EF-0. Note there have been no tornadoes so far this year in Oregon.

But we still have three months to go! And autumn has been a good time for tornadoes in our area. It’s interesting that mid-winter and mid-summer have the lowest chance of tornadoes; probably because we don’t get many showery patterns in July/August. And in mid-winter the showers are weaker and thunder is more rare for inland areas.

Of course most of these tornadoes are weak. The vast majority the past 70 years have been in the EF-0 and EF-1 categories.

I often get two key questions about tornadoes:

Are there more tornadoes in the region than we used to see? Becoming more common?

The short answer is NO. Remember that 30 years ago almost no one was walking around with a camera attached to his/her hand (constantly). Now EVERYONE has a high quality camera just a second away from use. Think about it; there’s a good chance that in pre-internet times, the storm in Battle Ground wouldn’t have been noticed except by a few homeowners wondering why part of the tree is across their lawn. And how many of them would have taken the time to call the Portland NWS office? There’s a reason that almost all reported tornadoes in the PACNW have been in populated areas. And the actual reported numbers have not increased dramatically either.

Is there some reason Clark County seems to attract tornadoes? A new “Tornado Alley”?

YES & NO. We have seen a couple of significant tornadoes in Vancouver (2008) and Battle Ground (2015) the past 20+ years. Those two were the most destructive. Other weaker tornadoes touched down in Salmon Creek (2017), Orchards (2017), east of Battle Ground (2013). The only deadly tornado on record in the Pacific Northwest was the F-3 that tore through Vancouver in April 1972, killing 6. A great study by Dave Elson at Portland NWS found that horizontal rolling of the southwesterly flow coming off the Tualatin Mountains (West Hills) may contribute to increased frequency downwind of that NW to SE topographic barrier as you can see in this image.

You can find his presentation here: https://www.ametsoc.org/chapters/oregon_archive/Minutes/2008/2008_11_20_Minutes_Powerpoint1.pdf

But no, there’s no new “tornado alley” developing in our area.

That’s it for now. Enjoy the (mainly) dry weather Wednesday. After more showers Thursday, October starts with 4-5 dry days.

Chief Meteorologist Mark Nelsen

Rain Is Back This Evening As A “Wet” September Wraps Up

9pm Sunday…

I was on vacation and missed the big downpours last weekend so I’m happy to see my first rain of the season tonight. I took a much-delayed “Graduation 2020” trip from New York City to Washington (DC), then down to very sweaty/hot Florida with part of the family. It was soooooo nice to fly back into PDX on a clear evening late last week and feel the low humidity. It’s not perfect, but we live in a nice climate don’t we? Of course it’s “pics or it didn’t happen” nowadays, so here you go

Alright, moving on to the rain…models were right on showing a nice day today followed by light evening rain. We hit 75 in Portland today, down about 10 degrees from the very warm mid 80s yesterday. Notice the 60s up in Puget Sound with showers off/on all day

We may not have broken the all-time record for 90 degree days, but Portland has never seen so many 85+ or 80+ degree days. Yesterday was the 90th day at/above 80, a new record

Radar shows one band of rain moving through the I-5 corridor right now and another offshore. That should arrive around 2-4am. This is the leading edge of a cool upper-level trough. It swings through the region Monday night and Tuesday. It’s a pool of cool air dipping south, you can see the lower-than-normal heights (cool colors) on the Monday night 500mb map

Then by Thursday the trough is gone, replaced by weak high pressure and higher than normal heights (warmer colors)

So we have two days of the usual spring/fall showers and sunbreaks pattern. Those are the days when we get sunbreaks, then a downpour 10 minutes later, then sun pops out for 30 minutes, repeat… This is also the setup (Monday and Tuesday) for scattered thunder/hail showers too. I noticed Lifted Index (a measure of instability in the atmosphere) is around zero or below both days along with CAPE up a bit too. A pretty obvious signal for isolated thunderstorms in our climate west of the Cascades. During the event last weekend some areas picked up 3-4″ of rain! This time it’ll be more like 1-2″ in the wetter parts of the metro area near the Cascades, and .50-1.00″ in the lowest elevations. Unfortunately with westerly flow you won’t see much in the lee of the Cascades. Less than one tenth of an inch for some of you in Central and north-central Oregon. The GRAF model gives us these numbers for rain by Tuesday night

Notice the Cascades and Coast Range could get 2″ or so in the wetter locations.

Portland has experienced quite a few “wet” Septembers lately; six consecutive years. Actually two of them were close to normal. Most often the rain has fallen in the 2nd half of the month like it did this year.

And you can see PDX and northern parts of the metro area are running well above the Willamette Valley totals for September rain due to the downpours early Sunday morning last week

Last weekend’s rain put fire season on life support. This rain event will put the “nail in the coffin” for sure. Even after six days of dry and warm weather, those Cascade fires were barely putting out any smoke yesterday/today and we’ve seen almost no increase in acreage burned. This event will finish things off. About 200,000 acres have burned in the Oregon Cascades this summer! Much of it started from those thunderstorms that moved north along the mountains the last few days of July and August 1st-3rd.

Are we entering a days/weeks long rainy period? I don’t think so. We’ll be dry Wednesday, then a weak warm front gives us sprinkles/showers Thursday. By next weekend, heights are rising and the early fall jet stream has been pushed far to the north again. It’s possible we have a very warm first weekend of October on tap.

The ECMWF 24 hour precipitation ensemble chart shows good agreement on dry (circled) Friday through Monday, then possibly some showers return next week at some point. Both GFS and GEM models are similar. This is about as normal as it gets for early October. A little wet, then dry, then a bit of wet again…

SUMMARY

1. Some nice wetting rain falls the next two days, probably up to 1″ in valleys and 2″ or so in Cascades
2. Mainly dry Wednesday through NEXT Monday except for some light showers Thursday
3. A mix of sun and clouds is likely Wednesday and beyond.
4. Temperatures average near normal the next 7-10 days
5. I’ve been waiting for a cool/wet day to clean my garage and workshop…it’s time.

Chief Meteorologist Mark Nelsen

Weekend Rain Slow To Arrive = Drier & Warm Friday

8pm Wednesday…

I’ll be on vacation and out of town Thursday through most of next week, so here’s a quick update. It’s too bad I’ll miss the first soaking of fall this weekend!

Here’s the plan:

• The next two days (Thursday/Friday) will be all or mainly dry from Portland south and east. Temperatures warm into the upper 70s the next two days too. There COULD be a sprinkles or a light shower during the daytime Friday, but that’s it.

• Real rain, “the soaking”, doesn’t begin until sometime after sunset Friday evening. At this point it appears high school football games could be dry; or at least you shouldn’t see any downpours

• The bulk of heavy rain (about 1/2″ in western valleys), falls Friday night through early Saturday morning.

• Showers continue off and on Saturday, although they may not be very intense. Expect the usual downpours, then sunbreaks, then a rumble of thunder etc…

• Sunday appears to be the wetter of the two days this weekend. More frequent and intense showers are likely. This can be the setup where we get funnel clouds too.

• It’s back to warm and dry weather most or all of next work week. This is a “one-shot” deal, not the beginning of a cool and wet period.

In general, weather forecast models have been in good agreement on the wet pattern this weekend. A cool and broad upper-level trough settles over the Pacific Northwest late Friday through Monday. You see the much lower than normal heights (around 18,000′ up in atmosphere) midday Sunday.

Ahead of that cool trough, a wet Pacific frontal system first aims at Washington state on Friday. This is the change the past 24 hours. Originally models were thinking the system would be farther south to start. But now it’s obvious just about all rain remains in Washington on Friday. THEN, Friday night and Saturday it slides south through Oregon. In the end our total rainfall is still the same mentioned (previous blog post) a few days ago; about 1″ or so in the western valleys by the time we dry out Monday. This is the morning ECMWF model. It’s interesting that both GFS and ECMWF ensembles show about 1.5″…good agreement.

And you see the widespread 2-3″ in the Coast and Cascade ranges. This will put Fire Season 2021 partially into the grave. There won’t be much left of those fire complexes burning on the west slope of the Cascades.

Sunday’s snow level (the lowest elevation we’ll see sticking snow) in the Cascades is close to Timberline Lodge…could be a mix there, or even a dusting by Monday morning. But of course it’s too early and too warm for pass elevation snow.

After a few leftover (light) showers Monday, it’s back to mainly or all dry weather next week.

I see about 1/2 of the European’s model ensembles generate measurable rain again AFTER this weekend in the last week of the month. But 1/2 do not. It would be perfectly normal to see a round of showers again in the last week of the month. That said, my gut feeling is that the last week of September will be much improved from this coming weekend!

Enjoy the rain this weekend! After 3 months of dry weather, FOLLOWING the driest spring on record, we desperately need it. I will be back at work that last weekend of the month.

Chief Meteorologist Mark Nelsen

Good News…Rain Is On The Way!

9pm Sunday…

What a nice early fall weekend; partly cloudy (& dry) sky plus comfortable temperatures. I drove through a couple spots of drizzle midday on the way to work, but it was not measurable. Yesterday we were a few notches above average; today a few below.

The next two days will be similar with more sunshine than cloud cover. Wednesday a weak/dying cold front moves overhead. The main result will be cloudier skies (like today) PLUS spots of morning drizzle or a shower. Thursday should be uneventful as well. So other than a shower/drizzle chance Wednesday morning, not much happens through Thursday and your life will be un-affected by any real weather. Then on Friday things change…rain arrives (yes, real rain) and we may have 4 wet days on tap.

HIGHLIGHTS

• The endless dry days we’ve seen for 3 months (since mid-June) come to an end this coming weekend
• Expect whatever you have outside to get soaked Friday through NEXT Monday…around 1.00″ rain in the lowlands
• This won’t help the drought much, but at least the top layer of soil will finally moisten up
• All Cascade wildfires will see chilly temps, high humidity, and a good soaking.
• After next weekend, Fire Season 2021 will be on life-support over/west of the Cascades; we are going to avoid a long episode of smoke and huge fires west of the Cascades this year. A good ending considering how bad things were looking by late June (drought + driest spring + extreme heat). A lack of lightning for most of August plus a cooldown late that month was a game changer.

The reason for a cooler/wet forecast next weekend?

Our first strong upper-level trough of the season. That means a significant dip in the strengthening early fall jet stream. Cool air pushing farther south than it has the past few months, spinning up several disturbances on the boundary with the warmer air. You can see the relatively flat flow now…no hot ridge of high pressure nearby

But check out next weekend. Our typical wet/cool weather pattern in both spring and fall

How confident am I that this is a real pattern change? Just one example…ALL of the 12z ECMWF 24 hour precipitation ensemble members produce some sort of significant rain Friday-Monday. That’s unusually high confidence. If only half of them were showing this I’d be a bit more skeptical. Also notice about half of these members bring in more rain as we head toward the end of September

Ensemble forecast temps also show we are headed into cooler weather

How much rain? The operational high resolution runs of the GEM, ECMWF, & GFS produce anywhere from 0.70″ to 1.20″ during this time in the western valleys (Portland, Vancouver, Salem). In this case it’s better to use the averages from the ensembles…which are in good agreement… Somewhere around 1.00″ or so in the lowlands of NW Oregon and SW Washington. Not a drought-buster, but enough to moisten things up quite a bit

You’ll notice in the comments above I’m quite optimistic about putting this fire season partially to rest. That’s because those ensembles also push 2-3″ rainfall into the Cascades, right over those 5 fires burning from north of Detroit down to east of Grants Pass. That’s enough to eliminate most smoke from those fires. That’s why I’m feeling good about that last few weeks of this fire season. Last year just under 2 million acres burned on the Oregon and Washington landscape. About a million of that was in the one week after Labor Day (easterly windstorm leading to mega-fires). So far we’re at about 1.4 million this year. We will likely end up with less acreage burned this year, even with a hotter summer and much drier spring conditions. By the way, last year on this date we were in the middle of that incredible 8-11 day stretch (depending on location) that featured the worst air quality we had ever seen in NW Oregon and SW Washington. Here are the numbers that we will be avoiding this year

That’s it for now, I just wanted to give a heads up about the wet weather arriving later in the week. I’ll plan on another blog post midweek with an update. Chief Meteorologist Mark Nelsen

End of Summer, Another Dry Water Year, & Looking For Rain

9pm Tuesday…

Since I last posted, we’ve seen August give way to September. Labor Day Weekend has come and gone too, a nice “end to summer” with abundant sunshine but no hot weather.

Of course meteorologically we just finished summer which runs from June to August. In Portland, Summer 2021 was just barely edged out by a slightly hotter Summer 2015. By 0.1 degree! Basically it was tied with 2015 for hottest summer on record at PDX.

In Salem, Eugene, Medford, & Redmond it was the hottest on record. As I’ve mentioned many times, Salem’s climate record is excellent, going back to the late 1800s. This summer was a scorcher!

This was our 9th consecutive warm/hot summer; of course not all of those were “hot”. Last year is a good example, just a bit warmer than average. 2012 was the last time we had a “cool” summer, mainly due to a very cool June. But 2015, 2018, & 2021 have been blazing hot. Portland has seen (so far) 24 days at/above 90 degrees. That’s at the higher end, but we’ve seen more in 2015 and 2018.

Salem has seen 39 days that warm; a new all-time record there. Eugene also set a record…41 days at/above 90 degrees!

Of course the drought continues… Portland has only seen .05″ rain in just under 3 months. And the six month period from early March through early September is the 2nd driest six-month stretch on record. Summer & early fall 1987 were slightly drier.

This means we are seeing another very dry “water year”. By the way, a water year is a term used throughout the Western USA. Since most precipitation falls in the cold season (straddling two calendar years), it makes sense to look back at wet seasons separately, which means starting the “water year” on October 1st each year and ending September 30th. We’ve got three weeks left this year. Right now it’s the driest since the 2000-2001 drought year…in Portland. We haven’t seen a wet year since 2016-17. Of course we could easily pick up 2″ rain the 2nd half of September, but even then it would be a much drier than normal year. Typically we get about 36″ in Portland each year.

Do we have any rain ahead? Not really, at least nothing significant through mid-month. A weak system drops a few showers tonight, then mainly or all dry through at least next Tuesday/Wednesday. Take a look at the ECMWF ensemble forecast chart for the next two weeks. It shows 24 hour rainfall. Each thin horizontal line on upper part of chart shows one of the 51 ensemble members. Time goes from now (left) to two weeks out (right).

Notice almost no members produce .10″ or more through the middle of next week, instilling high confidence that we’ll be dry through the 15th. But you’ll also notice around the 18th or so a lot of ensemble members say we could actually see rain. I’m not saying this is the case, but every few Septembers we get a big soaking the 2nd half of the month. In fact 3 of the past 4 Septembers we’ve picked up at least 2″ rain during that time.

It would be wonderful (and mainly finish the fire season) if we could get 2″ of rain in valleys plus 4″ in mountains the last ten days of the month.

One more note, it’s also obvious that we’re making a turn toward more typical (cooler) September temperatures starting Thursday. The same morning ECMWF model ensembles show temperatures consistently in the 70-80 degree range the next 10+ days. Summer is over…but warm early fall weather is here for awhile longer

Chief Meteorologist Mark Nelsen