What the hell is it?
* A corridor of fast-moving air that separates the cold air in the north from the warm air in the south that determines where storms form and where they move.
*Composed of wind currents high in the atmosphere (20,000 feet)
*During cold fronts, the jet stream bends south, but stays above the warm-cold boundary. In summer, the jet stream moves north toward Canada.
*Jet streaks are faster winds surrounding the jet stream that have a major effect on the location of storms and precipitation.
*A jet stream forms around high-pressure areas where wind tends to spin clockwise and low pressure areas that tend to spin counter-clockwise.
Mountains and Weather
*Mountains force moist, lower-elevation air to rise, increasing the chance of rain or snow. A phenomenon dubbed aptly, the "mountain" effect.
*As air rises over the mountains, in cools and falls on the other side as rain or snow.
*One side of the mountain tends to be much more wet and damp with a lot of precipitation while the other side can be dry and hold less amounts of precipitation. Oregon's Cascade range with its lush temperate forests to the west and arid high desert to the east is a good example.
Source from: phillipshs.wcpss.net
What to Expect
*Cold weather during February and March.
*A westward shift in colder-than-normal weather extending through Washington and the Oregon coast
*A dry February for Seattle and Portland, that holds a high chance for mountainsnow.
*Cascades are/were expected to receive an above average amount of snowfall for the season. (Not kidding!)
So What's Happening?
A strong La Nina pattern (colder than normal surface temperatures in the equatorial Pacific Ocean) is creating drought conditions for much of the West and the Plains states. meteorologist and climatogists aren't sure how the long the situation will persist, however the most recent forecasts indicate that current conditions will remain through mid-January. Despite the lack of precipitation and recent record-breaking warm temps, the La Nina phenomenon is expected to ultimately deliver increased precipitation and cooler overall temperatures. However, Climatologist Ken Clark said ski and snow enthusiasts shouldn't hold their collective breath.
"There's no guarantee the Northwest will see change in the current La Nina only because it first starting during the summertime and looking on the western side of the Cascades and Northern California, the area received only 2.5 percent of their average rainfall this season. And when comparing to last year's La Nina, we've seen a much drier climate and less precipitation," said Clark who maintains a regular blog on Western weather patterns at Accuweather.com