David49
Oregon isn't prone to high pressure areas any more than other places in the U.S. We have droughts in all parts of the country. Because the west coast has a wet season and a dry season if high pressure moves in during our wet season it really affects our annual totals. Our summer dry season is a function of our geographic location. The rest of the country has precipitation year round so when a persistent high pressure area moves in it can be offset by rain the rest of the year.