Another snow-free January in Portland, but are snowier Februarys becoming more common?

January 30, 2022

9pm Sunday…

Things are back to “normal” this evening. It finally rained this evening in Portland, our first rain in about 10 days, and a mild southerly wind replaced the chilly Gorge wind. The result was Portland’s warmest day in over a week as well. We touched 53 this afternoon, a bit warmer than a typical high around 49 this time of year.

A Warmer Day In Portland
A Warmer Day In Portland

A cold front is moving across Oregon & Washington, and much colder air has arrived overhead. This drops the sticking snow level down to around 1,500′ by tomorrow morning. No more inversion with temps in the 20s through the passes. Notice the very low snow level through Wednesday morning. Not quite cold enough for sticking snow in the city, although just scattered showers from this point forward would be a tough way to get sticking snow anyway.

Snow Level This Week
Snow Level This Week(mark nelsen | KPTV)

We’re overdue for a good snowfall in the Cascades and that happens the next 2 days. 8-12″ next 24 hours then another 6-8″ before we dry out Tuesday evening

Lots of Snow In the Cascades
Lots of Snow In the Cascades(mark nelsen | KPTV)

PORTLAND SNOW

Unless something miraculous happens tomorrow, Portland finishes another January WITHOUT measurable snowfall. Last year (January 26, 2021) a trace fell, but not enough to measure. This makes it our 5th consecutive January without snow.

January Snowfall in Portland
January Snowfall in Portland(mark nelsen | KPTV)

You are thinking “but wait, we’ve seen lots of snow in February recently haven’t we?”. That’s true. Check out the February numbers

February Snowfall in Portland
February Snowfall in Portland(mark nelsen | KPTV)

In fact, last February was the 2nd snowiest on record in Portland! It sure DOES seem like we’re getting more snow in February, compared to January. PDX records go back a bit over 80 years and I’ve taken a close look at the numbers. First, numbers for the last 30 years

Portland Snow The Last 30 Years
Portland Snow The Last 30 Years(mark nelsen | KPTV)

Just so we’re all on the same page. The blue bars represent ALL SNOW that fell in the past 30 years in any particular month. Divide that number by 30 and you get our average monthly snow fall. For example, we’ve seen a TOTAL of 51″ snow in Portland in the last 30 years = we average 1.7″ in any one January. You can add all those numbers up, divide by 30, and find we average between 4-5″ of snow each winter. Not exactly a snowy climate! Most interesting to me is that we are averaging more snow in February than December, and I remember more snow in December growing up in the 70s and 80s. Now look at the bottom row of numbers (in pale yellow). That shows the number of months in which measurable snow was recorded. Example: In 14 Decembers out of 30, measurable snow was recorded in Portland. Not 14 times, just 14 of those Decembers. So the 30 year average says we get snow in about 1/2 of the Decembers. So if you look at the number of months we’ve seen snow, December & January are still king. That means we’ve had fewer Februarys with snow, but more of it when it happens. Now look at the previous 30 years:

Previous 30 Years of Portland Snow
Previous 30 Years of Portland Snow(mark nelsen | KPTV)

This cuts out the mid 1990s to now. Quite a bit different and more like I remember. More snow AND more months with snow in December/January. Clearly there IS a trend toward more snow in February. Is it a long term trend? We don’t know, although I doubt that’s the case. With a slowly warming climate one would expect less snow in Portland and that would likely show up on the “margins”…November and late February/March. That may be the case, you notice both of those show less snow. By the way, I’ve done the 30 year calculations based on the assumption we DON’T GET SNOW THIS MONTH. That way I won’t have to recalculate next year if it doesn’t snow this year. Any snow in February 2022 will only add to the “late season bias” in snowfall the last decade.

We CAN get snow very late in the season, in March. In fact the 2nd latest on record was right when COVID was first shutting things down 2 years ago. Those snowfalls MOST of the time are light and followed by afternoons in the upper 30s and 40s. They don’t shut down the metro area.ADVERTISEMENT

March & Late Season Snow
March & Late Season Snow(mark nelsen | KPTV)

Do I see anything ahead that says we could get snow/cold in early February? Not for now. The mild/dry pattern continues until further notice due to a strong upper-level ridge that wants to remain just off the West Coast…through the next 10 days! This animation shows upper level “anomaly” the next 10 days. Warm colors are higher than normal 500 millibar heights.

Strong Ridging Along West Coast Through Early February
Strong Ridging Along West Coast Through Early February(mark nelsen | KPTV)

You can see the warming trend after midweek in the 15 day ECMWF ensemble chartADVERTISEMENT

Euro Ensemble Forecast Next 15 Days in Portland
Euro Ensemble Forecast Next 15 Days in Portland(KPTV)

IF that upper ridge were to back up slightly to the west, it COULD allow cold air to come in from the north. That happened in 2018 & 2019. For now models are generally not showing that happening in the first 7-10 days of February. That’s it for now…I’ll be on TV every evening this week, starting tonight… Chief Meteorologist Mark Nelsen


Drought Continues Across Much of Oregon

January 28, 2022

8pm Friday, January 28th, 2022

I have an unusually quick post this evening! You know I typically get into lots of detail, but we’re working on some new software so I’m performing a bit of a “test”. The current USDA Drought Monitor for this week. Notice how much of the state is still in severe to exceptional drought.

January 27th Drought Monitor
January 27th Drought Monitor(USDA)

The far northwest corner of the state was hit by those atmospheric rivers back in November and December, bringing many of us out of drought. Lack of heavy mountain snow this past month means much of the region is back to normal for snowfall this winter.

January 28th Oregon Snowpack
January 28th Oregon Snowpack(USDA)

We’re going to need a lot more snow/rain to get the state out of drought!

The local American Meteorological Society (Oregon Chapter) just had a meeting last night featuring our state climatologist. Most of the presentation was about our ongoing drought across the region. You can see the whole meeting here

That’s it…enjoy the dry Saturday and then rain returns later Sunday

Chief Meteorologist Mark Nelsen


Another Snow-Free January Plus A Look Into Early February

January 25, 2022

8pm Tuesday…

Here we are in the last few days of January; time is flying! It’ll go down as a mild and uneventful month…after that stormy/rainy first week.

MY THOUGHTS ABOUT THIS WINTER SO FAR

  • Temperatures have been about normal. Warm November, Cool December, then slightly warm January. Nothing real interesting.
  • Precipitation is still above normal for this water season that starts October 1st. Right now PDX is just a touch under a typical January rain-wise. But rain/showers Sunday & Monday should put us just a bit above average for this month. We haven’t had a drier than average month since August!
  • Snowpack is running near normal for late January across most of Oregon. But it’s still well above average in the northern/central Oregon Cascades. If we want to get out of the drought still plaguing much of the state, we’re going to need a wet/snowy February and March! Just “average” isn’t going to cut it.
  • Those 7 days at the end of December were fun with snow at times in the lowlands, but outside of that we haven’t seen any more snow or freezing rain.

LOOKING AHEAD…

  • There’s no sign of a big arctic freeze or widespread lowland snow through the first week of February
  • Stormy weather (strong south wind or heavy rain) is unlikely in the next 10 days
  • Most likely we’ll be drier than normal the next 10 days

You can see the stats for PDX this water year…a bit under 2 FEET of rain this season so far

About double that at Astoria, around 4 FEET of rain

Lots of that was “warm” rain in October, November, and early January. So snowpack about average now across much of Oregon, but better up in NW corner

The weather pattern is relatively straightforward this last week of January and into first few days of February. Big upper-level ridge overhead has been keeping us dry. Warm mountains/beaches and cool (normal) valleys. Please appreciate the nice 1st grade quality annotations I’ve put on these maps.

By late this Saturday the ridge has weakened and a cool trough (dip in jet stream) is approaching

By late Monday a transition has occurred. The ridge wants to pop up again just west of the West Coast. This is a cool-ish pattern for us; a cold trough is dropping through the Pacific Northwest.

Snow levels will crash Sunday through Tuesday. For the weather geeks, 850mb temps down around -5 to -6 Monday/Tuesday. If there are still showers around, a dusting is possible above 1,000′ during that time.

Finally some snow in the Cascades!

Models have been waffling around a bit about what occurs those first few days of February. The ECMWF and GEM have been insistent on keeping the ridging nearby for a drier than normal weather pattern the first week of February. The GFS (surprise!) keeps wanting to dig a cold trough south over us at some point next week, down the back side of the ridge. Notice the difference in placement of the upper-level height anomaly. GEM/ECMWF look like this for February 1st-7th. Mild and drier than normal

ECMWF is especially pathetic with lowland snow, giving us almost no chance through February 8th

Meanwhile, look at the GFS keeping ridging a bit farther west the first week of February. Still drier than normal, but some cold troughs would swing much closer to us for a very cold Rockies/Central USA

That’s it for now. Enjoy the fog/sun mix the next few days!

Chief Meteorologist Mark Nelsen


A Mild January! No Sign of Cold, Snowy, or Stormy Weather

January 17, 2022

9pm Monday…

We just “endured” a 2nd consecutive dry weekend, and we’re likely headed for a 3rd. How many times can you remember several rain-free January weekends in Portland? Rare, although not unheard of.

As mentioned in my post 9 days ago, the weather pattern changed after the first week of January. We’ve only seen .30″ rain in 10 days!

That’s because the jet stream has been weaker and farther north (than typical) the past 10 days. It appears this continues for ANOTHER 10 days. The highlights, which look very similar to my post from 9 days back…

  • All models agree the next 10 days will feature mild weather with relatively weak weather systems
  • Temperatures remain near or above normal through at least 27th
  • There’s no sign of a cool/wet pattern OR low elevation snow/ice west of the Cascades during this time
  • A cool and/or snowy January isn’t in the cards for this La Nina winter.
  • But we don’t know what is ahead for February; there’s always a chance we get “Winter v2.0” next month

Check out the 500 millibar anomaly forecast from the ECMWF model for the next 10 days. Warm colors are higher than average heights and cooler = lower. Those colors generally correspond to warmer/cooler down here at sea level too. So yes, a mild western USA and frigid (at times) Eastern USA for at least the next 10 days. If you can’t see the animation, try here

3 weak systems make it through the weak ridging this week, tomorrow through Thursday. I expect less than 1/2″ rain in the western lowlands. Then that ridge pops up this weekend, even stronger. Check out midday Saturday 500mb GFS model forecast; other models are similar. That’s a very warm ridge!

Depending on the exact location of that ridge, we will get either some or strong offshore (easterly) flow. That will determine whether we have another fog/clouds episode in the valleys or turn sunny. I’m feeling very confident that next weekend could be spectacular along the coastline. No, no one is giving me free saltwater taffy (for example) to write this. But inversions aren’t as much of a problem out at the beaches; some of you could hit the 60s along the coastline either Saturday or Sunday.

This winter is running close to average so far. December slightly cooler than average (at PDX) and January slightly warm. Official numbers for December are out and it was cooler than normal in western Oregon and warmer than average (just a bit) east of the mountains. Remember the really cold air only briefly moved south into northern Oregon last month. My gut feeling is that this present mild/dry spell in the middle of our La Nina winter is likely just a break from the cool and wet. I’d be VERY surprised if we stayed dry/mild into February/March. By the way, the USA as a whole was very warm!

That’s it for now, enjoy the rest of the week!

Chief Meteorologist Mark Nelsen


Big Weather Slowdown Heading into Mid-January

January 7, 2022

9:30pm Friday…

The big rain showed up as forecast. An atmospheric river of moisture, also known as a pineapple express, was aimed at southern Washington and extreme NW Oregon the past two days. Rain totals were not excessive from Portland south, but very heavy rain fell to our west, north, and east (Cascades/Gorge). The numbers from the past 3 days

Notice those numbers around 7″! Astoria saw its 2nd wettest day on record at the airport.

When records were kept in the city before that time, there were 2 wetter days in 1919 & 1904. Regardless, this was a high-end rain event on the far northern Oregon and southern Washington coastline. Check out the REALLY big numbers. Over 9″ in several spots, including the south Washington Cascades and Willapa Hills in SW Washington

I-5 in Chehalis just briefly closed today as Chehalis River water came up onto the edges of the freeway, but luckily it was 4 feet lower than during the huge 2007 flood. Just about all rivers are receding now and I think we dodged a bullet this time; no widespread heavy rain like in 1996. That year over 15″ rain fell all through the Cascades over a 4 day period, melting lots of the snowpack.

The good news is that the snowpack is still there in the Cascades, running well above normal

WHAT’S AHEAD

  • The next 7+ days feature a very quiet weather pattern; no big storms/weather systems moving through the region
  • Temperatures remain near normal through at least the 15th
  • There’s no sign of a cool/wet pattern OR low elevation snow/ice west of the Cascades
  • All models agree the next 10-14 days will feature mild weather with relatively weak weather systems
  • The “holy grail” of a cold/snowy January (for weather geeks like me) isn’t going to happen this year

It’s quite the pattern change coming up. We’ve had cool upper-level troughing near/over us most of the time since around the 10th of December. Now for the next two weeks it’ll be more like that mild weather that we started with in November and early December. Here’s the 500mb pattern on Monday

Warm upper level ridging overhead, but it’s a “dirty” ridge, meaning weather systems are brushing us early next week (red lines). We also don’t tend to get insanely strong east wind inversions with this setup. By NEXT Saturday, the 15th, it hasn’t changed much. Time for winter to arrive in the eastern USA! This is quite the flip from the past month.

Then even farther out, Friday the 21st. This is the ensemble average 500mb height anomaly, showing above and below normal heights. The same GENERAL pattern continues (Canadian ensembles shown)

Is winter over? Of course not, that would be ridiculous to proclaim on January 7th. But this is a big slowdown after the weather drama the past three weeks!

Looks like ONE ensemble member of the 30 GEFS members tries to bring snow down into the valley…in the next two weeks!

Seems like an excellent time to take my snow-blower in for repair. I did use it with that one snowfall of around 4″. I know…sad.

So…enjoy the much slower weather this upcoming week. Sunday WILL be spectacular with mainly sunny skies all day in much of the metro area. We’ve got strong offshore (easterly) flow, which should clear the fog out most areas west of the Cascades. Too windy in the western Gorge of course, but it’s January, it happens.

Chief Meteorologist Mark Nelsen


Busy Weather For First Week of 2022

January 5, 2022

10pm Wednesday…

It’s been awhile! I took a few days off last weekend (Happy New Year!) and then things got REAL busy weatherwise. Lot of extra work…

Of course 2021 ended very cold. New Year’s Day and last Monday were both the coldest of winter so far…only 34 degrees. And New Year’s Day included a lot of sunshine too! That was a very cold airmass pouring through the Gorge.

We ended up with 0.3″ on December 30th, which made for the snowiest December since 2008 at PDX

As always, some of you saw significantly more, some less. I ended up with 9″ at my home (1,050′) for the month. We never did get a big arctic blast across the entire Pacific Northwest, but the shallow edge of the really cold airmass punched down into northern Oregon a few times last week. PDX dropped to 25 on New Year’s morning Saturday. It was amazingly cold that morning north and east of Portland. The -22 appears to have been an all-time record cold temperature in La Grande.

A surface low pressure system passing by to the north warmed us quickly Sunday night into Monday and we avoided a “transition snowstorm” in the metro area. But that storm also brought a HUGE dump of snow to the Cascades, Gorge, and blowing snow in northeast Oregon. Snowfall on Mt. Hood from Sunday evening to last night when things died down. 3+ feet is a big snow total for just two days on the mountain! At one point US26, OR-35, & I-84 (the entire Mt. Hood Loop) was closed to traffic.

With that cold airmass still locked in over north-central Oregon, big snowfall showed up there too. This was the biggest snowfall in several years. A few picks from viewers

Looks like somewhere between 20-35″ fell in most areas from Bonneville Dam to Hood River. There are very few official observation sites in the Gorge. Hood River had a long term site all through the 1900s but those observations stopped around 2012. Bonneville Dam officially recorded 18.0″ & Cascade Locks 21.5″. When the January stats come in next month, we’ll see how much Parkdale officially picked up.

Lighter amounts fell both east & west of there. BTW, the all-time daily record at Bonneville Dam is 39″, Hood River is 47″, and Parkdale 37″…all in early January 1980. That Hood River number is also the record for the entire state! The TWO DAY record for Bonneville is 53″ during that 1980 event, so this week’s snowfall was the 3rd highest on record during any 2 day period. This WAS a historic event out there.

The very last thin layer of cold air is still in the Gorge this evening. I see 3″ new snow at The Dalles this evening, so it’s safe to assume 3-6″ has fallen deep into the Gorge around Hood River. That changes to freezing rain overnight as much warmer air is arriving overhead.

We are under a flood watch this evening, and it’s been raining all day. Tomorrow an atmospheric river will be aimed just north of us. Latest GRAF numbers look like this…

That’s a lot of rain, but nothing really dramatic in the valleys south of Longview. We should get some flooding north of Portland, especially on streams/rivers draining the Coast & Cascade ranges.

We’re headed into a much calmer weather pattern beginning this weekend. After 3+ weeks of cool and wet systems, upper-level high pressure wants to linger around the West Coast this weekend and all through next week. There’s no sign of low elevation snow for the next 10-15 days…the first half of January, and possibly through the 20th, will be mild. At this point it sure doesn’t look like a cold/wet January is in the works. But a lot can happen the last 10 days of the month…you never know!

I’m watching Friday morning closely too. Models want to develop a surface low offshore and have it race across the region, possibly just north of Portland = strong south wind? We will see. More tomorrow if that’s the case. We haven’t seen a windstorm in the western valleys yet this season!

That’s it for now, the 10pm show beckons… Chief Meteorologist Mark Nelsen