Downslope Drying

In the midst of a Front Range deluge, drier air is moving into Metro Denver this evening.  The moisture flow is currently from the south, moving northward along the mountain wall and the adjacent Piedmont.

To our south, heavy rain is falling in Colorado Springs and across the southern flank of the Palmer Divide.  North of that divide (which has an elevation of about 7500 feet), the air descends with the terrain; in concert, its dew point falls (the air is compressed and warms up).  North of Denver, the air rises out of the South Platte Valley and into the foothills; this upsloping air cools, condenses and drops its precipitation once again.

By tomorrow afternoon, the wind is forecast to shift back from the northeast, producing classic upslope conditions along the Front Range, primarily north of the Palmer Divide.  Afternoon thunderstorms will progress to widespread rain which will turn to snow by Sunday morning.  For now, we'll enjoy a brief period of downslope drying.