In most cases, a moderate to strong push of marine air will follow, along with strong, gusty, west winds along the east slopes of the Cascades. Gusty winds and thunderstorms can be associated with the passage of a thermal trough. This term refers to the changes in temperature, relative humidity, wind speed, and fuel moisture between one day and the next. The trends delineated in the daily narrative forecasts are area wide averages for the extreme part of the day. Unstable conditions are favorable for turbulent surface winds and erratic fire behavior.
Smoke generally disperses well in an unstable atmosphere.
Often referred to as a high or low aloft. They occur in the upper levels of the atmosphere and may or may not be reflected at the surface. An appreciable amount of continuous rainfall over a broad area. Usually greater than .10 inches. Wind speed and direction measure at eye level.