Tag Archives: thanksgiving

Thanksgiving Weather Map: Rain And Snow Could Disrupt Travel

Even the Rockies are too low and smeared out. There will be advances that we can not even imagine now. The results I have shown you above are just the tip of the iceberg on what we can explore with these model runs. Not good. One thing my group at the UW has shown is that you have to run weather prediction models with roughly 12-km or better grid spacing to have any chance of getting our local weather and climate correct. In fact, most global models are run with grid spacing of around 150 km, which makes them unable to simulate the impacts of the crucial terrain and land-water features of the Pacific Northwest. A number of research projects have only made use of one or two climate models. How aggressive an increase in greenhouse gases should we use? The runs described above represent the best guidance now available for how global warming will influence our region if nothing is done to address greenhouse gas emissions. These global models are driven by estimates of how greenhouse gases, like CO2, will increase in the future. Both strong La Nina’s and El Nino’s featured above normal snow which to some might seem like a counter-intuituve result.

For outer clothing they need a waterproof coat, boots and snow pants. If you live near the Great Lakes, especially Michigan, Huron and Superior, get ready for what could be a big lake effect snow event when this part of the LRC repeats again. Should we assume that folks would “get religion” about climate change and radically reduce their emissions or should we use a “business as usual” continuation of recent trends? The Northwest will not dry out under global warming–we will generally get wetter. By the end of the century, there will be substantial warming, with the average summer day around Puget Sound climbing into the mid-80s, rather that the upper 70s of today. Our typical winter day west of the Cascades will have a high around 50F. Cascades snowpack will decline substantially on April 1st (about 50% below today’s value at 5000 ft). Here is the are the April 1 snowpack for 1970-1999, 2030-2049, and 2070-2099. Modest declines over the lower-elevation terrain by mid-century.

Next, let’s look at changes to our snowpack. Securing a realistic estimate of the local impact of global warming is critical if we are to take steps to ensure resilience to the expected changes. They had real insights into our local weather. “Wintry weather will produce some difficult travel conditions across parts of the Eastern U.S. Keeping gutters clean and free from debris will also help to prevent flooding. This tells us that the cold air up in Canada is more free to move around, rather than maintain its position, locked in the Arctic Circle. But by the end of the century (2070-2099, think 2085), the average over the region will be twice that (around 4C increase, about 7F), with considerably more warming in the interior. Looking at the annual average of maximum temperatures, there will be roughly a 2C (about 3.6F) warming in maxima by 2030-2059–think 2045 (click on figures to enlarge). I don’t think there will be skiing in Snoqualmie Pass in 2085 if the warming is not reduced.

There are many interesting questions that can be addressed with such climate simulations. Since people can choose from various designs the cost can differ depending on the design and they have to think about the budget before finalizing everything. Let’s pretend that scientists (meteorologists in this case) have built some software that predicts where hurricanes will make landfall. But we had a major decision to make. Let me say, that I believe that the RCP 8.5 scenario will turn out to be too pessimistic (aggressive) by the middle to the end of the century. Temperatures below freezing will become rare by the end of the century here in Seattle. You will notice a steady rise over the century–nothing abrupt. Although weather forecasting technology has improved dramatically over the past few decades, forecast skill–the ability to predict specific weather features– fades in time. Lots of variability, but it looks like there will be a small drying (perhaps 1 inch over the summer) by the end of the century.