Mountain & valley winds, chinook & bora
Slope winds reverse daily: up-slope by day, down-slope at night.
| Wind | When | Flow | Cause | Term | Cite |
|---|---|---|---|---|---|
| Valley breeze | Day | Up-slope, out of the valley | Slope air heats faster than valley-floor air; cloud may form over slopes | Anabatic | AWH 10.6.4 |
| Mountain breeze | Night | Down-slope, into the valley | Slope air cools faster, gets denser than valley air | Katabatic | AWH 10.6.6 |
Chinook and bora: downslope windstorms on a mountain range's lee side. Opposite temperature and timing.
| Wind | Timing | Temperature | Cite |
|---|---|---|---|
| Chinook | Prefrontal | Very warm | AWH 16.2.6.4 |
| Bora | Post-cold-frontal | Cold | AWH 16.2.6.4 |
- Chinook common on eastern slopes of the Rockies.
Trap: swapping pairs: valley breeze is up-slope by day, mountain breeze down-slope at night; chinook is warm, bora cold.
References
- FAA Aviation Weather Handbook (FAA-H-8083-28) 10.6.4
- FAA Aviation Weather Handbook (FAA-H-8083-28) 10.6.6
- FAA Aviation Weather Handbook (FAA-H-8083-28) 16.2.6.4