Weather Library
Downslope Wind
Saturday February 2, 2008 01:28 PM
This satellite image from the afternoon of February 2nd, 2008 clearly illustrates "downsloping winds." A downslope wind is simply a wind that blows from a higher elevation (a mountainside) to a lower elevation (a coastal plain or valley) over an extended distance. In this case, west to northwest winds are blowing from the mountains of the interior Northeast (Catskills, Berkshires, Green and White Mountains) to the coastal plain of the Mid-Atlantic and New England. When a downslope wind occurs in New England, it's not unusual for Cape Cod to have some of the nicest weather in the region. Why?
A downslope wind produces sinking motion in the atmosphere. This sinking motion:
- Causes compressional heating - which allows the air to warm significantly when compared to its origins.
- Inhibits cloud development - the downward motion counteracts the effects of rising air and causes clouds to dissipate.
The 1PM observations around the Northeast from Saturday Feb. 2nd support this:
Hyannis - Sunny skies and 49°F.
Worcester, MA - Partly Sunny skies and 37°F
Albany, NY - Cloudy skies and 35°F.
