I've been watching the weather over the past few years and have noticed a persistent pattern. A huge dome of high pressure anchors itself over the Western U.S., causing above normal temperatures and below normal precipitation there, and causing the jet stream to dive down over the Midwest and Eastern U.S., causing rainy, cool, often below normal temperatures here. If you look at the Climactic Prediction Center forecast page, you see the pattern. Above normal temperatures in the Western 3rd of the country, Alaska and southern Florida. Below normal temperatures in the Midwest and East. We also had a pattern very similar to this in 2000 - 2004. Is there a known cause for this pattern? Is it a known pattern, or is it just me noticing it? I love summer weather and am wondering when we'll heat and sun back in the East.