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What is going to the climate and local weather be like within the northwest in 2050?

Reposted by The Cliff Mass Weather Blog

Sunday October 18, 2020

What will the weather and climate be like in the northwest in 2050?

The future of the north-west climate is widely debated and debated these days.

Knowing the future climate is very important as we can take steps to adapt to climate change and save lives and property. And the risk of unpleasant consequences can motivate society to take measures to reduce carbon emissions into the atmosphere and increase carbon storage in the soil.

A number of politicians have made climate change a core part of their political platforms, and a number of natural disasters (such as forest fires, droughts, and storms) have been attributed to increases in CO2 and other greenhouse gases. A free naming has followed this topic with terms such as “denier”, “alarmist” and “warmest”, which are just a few of them.

Climate change has become such a point of contention that activist groups have pushed for radio commentators to be removed who do not follow their line (e.g. Seattle350 urges KNKX to remove a specific meteorologist). For some it has become an issue of almost religious intensity, with "thinking right" on the subject being an important way of demonstrating that one is a true "progressive".

Now let's clear the air a little. I will show you that Gold standard of projections of what will happen here in the northwest over the next three decades due to increasing greenhouse gases.

It's a timescale short enough to give me great insight into weather and climatic conditions in the northwest in my opinion as CO2 continues to rise.

Everyone of you You can take into account the projections and judge for yourself whether it is an "existential" threat, a serious threat, an inconvenience or an improvement on our current climate. You decide.

The gold standard of regional climate projections

My group (specifically Richard Steed and Jeff Baars) worked on the most advanced regional climate projection capability in the region in collaboration with Professor Eric Salathe of UW Bothell.

In particular, we have been conducting an ensemble of TWELVE high-resolution regional climate simulations (12 km grid spacing) for 130 years (1970-2100).

Each of these simulations was driven by a different global climate model. Such global models have such a crude resolution that they make profound mistakes in our local terrain. So we applied a proven High Resolution Weather Forecasting Model (WRF) to properly simulate regional weather effects and ran it for 130 years.

Global climate model (left) compared to our high-resolution regional model (right).

We have assumed that in our simulations Worst case scenario to increase greenhouse gases (known as RCP 8.5), which implies increasing use of coal and fossil fuels. CO2 increases rapidly.

The reality is likely to be more harmless as renewables go online, the use of coal declines, and hopefully the use of nuclear energy (both safe fission and fusion) will revolutionize. And as energy sources increase, the sequestration of CO2 (removal from the atmosphere) becomes more profitable.

Our work required enormous computer resources, much of which was provided by an EU grant Amazon Catalyst Program. The Amazon folks also helped support some of the researchers who completed and analyzed the output and guided us in using cloud computing. So a big thank you to Amazon.

What I'm about to show you is unique: no other regional climate forecast offers such a high-resolution view of the future climate of the Northwest or information about the uncertainties in the projections.

Precipitation

There is a lot of talk about the climate change that is bringing drought to the region. So let's see what the latest models suggest.

I will first show you the change in annual rainfall in the region between 1970-2000 (think 1985) and 2030-2060 (think 2045). This graph shows changes in the averages of all twelve forecasts. The average one ensemble of many forecasts is generally more adept than the individual forecasts.

For most of the region there is annual rainfall increase by 1 to 4 inches, with some decreases on the leeward (upwind) side of some important terrain barriers. In general, MORE water for our region every year. Good news.

What about in summer?

For about 2/3 of the region, the amounts will go down, but most of the declines will be small (0 to 0.5 inches). The largest declines (up to about 1 inch) will be on the west side of the Cascades and the west slopes of Vancouver Is. Interestingly, there will be a small increase in some regions, particularly east of the Cascade Ridge, with the largest increase being in the northern Rocky Mountains.

Conclusion: On the dry east side of Oregon and Washington no major precipitation decreases.

What about Seattle? What kind of precipitation can you expect and how good are our simulations? Good question.
The main precipitation period is in the middle of winter … and below you can see a representation of all ensemble members, the average of all (green line) and the observed values ​​(black point) for 1970-2100.
A very small upward trend in winter rainfall through 2050. You won't notice it. Also note that the observations weren't very trending either.

What about summer (June through August) in Seattle? The forecast is below.
ONE very slight downward trend. Summers around Puget Sound have always been dry (usually 2-3 inches in total) and maybe by 2050 we will lose as much as 0.5 inches to global warming.

How about Omak in the fire-prone mountain region in northeast Washington? As shown in the projections below, it's a dry place with little trend.

The bottom line of these forecasts is that the changes in precipitation in our region will be small by 2050, even if greenhouse gases increase rapidly over the next few decades.
temperature
Increasing greenhouse gases will have a significant impact on our regional temperatures, but how much? Let's look at the maximum temperatures.
Annual average maximum temperatures through 2030-2060 (think 2045) will rise 1-2 ° C west of the Cascade Ridge and 2-3 ° C (4-5 ° F) east.

What about the summer we worry about heat waves and forest fires? Significantly greater temperature increases (see below). Along the coast almost the same as in winter – 2 ° C or less temperature rise. Ocean temperatures aren't warming as fast as the land, so heat continues to be released along the coast from Forks to Astoria to Lincoln City.
Summer temperatures in Puget Sound rise by around 2.5 to 3 ° C. So a typical Seattle summer high would increase from around 76F to around 80F.

East of the Cascade Ridge, summer highs rise 3-3.5 ° C, making the typical summer high in Richland, WA rise from 88 ° F to 93.5 ° F. Enough to get noticed.
Below is a graphical representation of how SeaTac's daily average December-February (C) winter temperature will change through 2050. The green line is again the average of the ensemble of regional climate predictions. A slow increase over time of around 2 ° C.

Summer temperatures are also rising steadily by around 3 ° C. Note that in 2020 we have already seen around half the greenhouse warming that is expected by 2050.

By the way, do you notice that the high-resolution model at SeaTac is too cold in winter and too warm in summer? This error is likely due to the lack of resolution even of the regional climate simulations, as the relatively narrow Puget Sound west of SeaTac cannot be defined.

Omak mean temperatures in winter and summer? A gradual rise, with summer temperatures rising 2-4 ° C over the period (and we're roughly halfway back by this point).

Omak winter

Omak summer
Conclusion: Assuming a worst-case scenario with increased greenhouse gases, the region will warm up, with the largest increase occurring east of the Cascade Ridge. Winter warming (from about 1985 to 2045) will be about 3F in the west and 5F in the east. Summer warming is about 4F in the west and 4-5F in the occupation. The warming is gradual and progressive.
Snow cover
If there is only a slight increase in precipitation but warmer temperatures, a decrease in the snowpack can be expected – and this is exactly what the regional simulations show.
Here is the change in snow cover on April 1st (snow water equivalent in mm), a critical measure of the availability of melt water for the summer between about 1985 and 2045. Notable declines (dark brown colors) on the western slopes of the Cascades and the Olympic Games. Some bumps in East WA (due to the increase in rainfall).

To get a more intuitive idea of ​​how the snowpack will change on April 1st, see below the ensemble projections and ensemble mean (green line) at Stevens Pass. You will find a great deal of variability in the forecasts and observations – the amounts of snow vary from year to year for a number of reasons (including natural variability like El Nino / La Nina). Over the entire period up to 2050 the snowpack Rejects from about 1000 mm (1 meter) to about 750 mm: a decrease of 25%.
It is not clear whether the observed snowpack (black dots) has so far decreased significantly.

The decrease in projected snowpack is less at higher points and greater at lower points such as Snoqualmie Pass. Skiing in Snoqualmie is often marginal today and I wouldn't buy a season pass there after 2030. My guess is that skiing in Snoqualmie will be history by 2050.
Wind speed The regional climate simulations do NOT indicate a large change in the average daily maximum wind speed (see below) between 1985 and 2045. The same applies to annual maximum gusts or the strength of approaching Pacific storms.

I can provide a thousand more graphics, but you have a general idea.
If CO2 and other greenhouse gas emissions continue at their current pace, our regional climate will change. In fact, some of the changes have already started. So by 2050:

Annual precipitation will increase slightly in most regions.Temperatures heat up by around 3-5F.Winds and storms will hardly change.The snow cover will decrease dramatically by 2050 (approx. 25%).

It is important that the model projections neither point to “turning points” nor to sudden changes in our weather / climate as a result of increasing greenhouse gases.
To say something that gets me in trouble with the climate activist people There is no existential threat to our region until the middle of the century. We will be able to adapt to the modest changes that are expected, although some will be worrying (loss of skiing at Snoqualmie Pass).

Not optimal snow conditions
I believe the above is the best available estimate of what unrestrained global warming will bring to our region by mid-century, and I ask activists and over-the-top "journalists" in some local media to limit their naming and naming restrictions Twitter anger when such information is transmitted. My previous radio station, KNKX, surrendered to climate activists – hopefully at the end of this season's political rancor, rational discussions and good science will be recognized again.

HT / Cam_S

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