Thursday was cooler and today will cool off even more. How is that happening. The best answer is that the high pressure ridge that has been over us has moved to the east over the state and an upper level trough of low pressure(that shaded area offshore) is sending cooler moist marine air into the interior of Oregon. That will cool us off more today and even more on Saturday. That moist airflow will produce some thunderstorms along the west side of the Cascades and in the foothills that could produce valley thunderstorms beginning as early as tonight and continuing through the weekend as  the low moves in closer to us. Look for a high near 85 for Eugene today and closer to 90 for the weekend. Farther south Roseburg will be in the low 90s with a chance of thunderstorms too cooling to the 80s by Monday.