Northeast Blizzard, Western Heat

As residents of the Northeast urban corridor brace for blizzard conditions tonight, those living along the Front Range or across the High Plains are basking in summer-like warmth; the afternoon high in Denver today was in the low 70s (F) and the warm sunshine is expected to continue tomorrow.

The snow and high winds from Philadelphia to Maine are courtesy of a powerful low pressure center off the Atlantic Coast which will sweep moisture across the entrenched cold air; the latter has dropped southward through an atmospheric trough (a dip in the jet stream).  By contrast, summer conditions in the West are developing beneath an atmospheric ridge (a northward curve in the jet stream) which is allowing warm air to flow up from the Desert Southwest; in addition, this air is descending across the eastern slope of the Rockies, augmenting its heat and dryness.

While global warming deniers will latch onto the Northeast blizzard to support their misguided view, they will ignore the January heat in the West.  In fact, both extremes reflect transient atmospheric conditions and are unrelated to climate change (unless, of course, global warming is fueling a more restless jet stream).