OCR Text |
Show Thunderstorms The thunderstorm is owing to the rapid vertical convection of air containing con-taining a large amount of water vapor. The lower air must, therefore, be rather rath-er warm, say 70 degrees F. or over, else it would not carry the requisite amount of water vapor, and the temperature tem-perature must decrease rather rapidly with increase of height, else there would be but little or no convection. Now. in the summer time the humidity humid-ity in Oregon and Washington is rather rath-er low. Hence thunderstorms generally gener-ally are improbable. In the winter time, v.ec most of the rains come, the surface commonly is too cool to set up vigorous vertical convection. Hence thunderstorms are not likely. Thunderstorms are not frequent in : Oregon and Washington any time of the year. Thunderstorms occur very infrequeatlv In California |