Throughout most of this winter, the jet stream has produced havoc across a large portion of the Northern Hemisphere. While it generally assumes a horizontal flow across central latitudes during the winter months, ushering in a series of storm systems and milder interludes, it took a different track this year and, until recently, seemed unwilling to budge. Its stagnant undulation produced dramatically different but equally unwelcome weather in adjacent regions.
Streaming northeastward into southern Alaska, the jet brought mild air and copious rain, significantly reducing the winter snowpack; at the same time, this northward shift deprived California of its usual Pacific storms, greatly exacerbating the State's ongoing drought. Dipping through the central and eastern U.S., the jet allowed Arctic air, displaced by the warm Pacific inflow, to plunge southward, bringing frigid weather to the Heartland and freezing precipitation to the Coastal Plain. After directing a series of storms across the Northeast, the jet stream took aim on Europe, lashing the west coast of England with high waves and flooding rains. Even Sochi, Russia, the site of the Winter Olympics, has been a victim of the fickle jet; unusually warm air has hampered efforts to maintain ideal snow and ice conditions.
Fortunately, this pattern has begun to break down. The Pacific inflow has shifted southward, dropping heavy snows on the Cascades and Sierra Nevada, and a more typical, west to east jet stream should put an end to Arctic outbreaks (at least for now). Hopefully, its menacing effects in Europe will abate as well.
