Changing pattern ahead, much colder weather over the weekend
The mild pattern this week will be coming to an end Friday as the ridge of high pressure breaks down. The ridge has been off the coast for the past few days, allowing the mercury to rise into the 50s in a few spots this week. That ridge is breaking down and migrating east and south, opening the door for a blast of arctic air to arrive Saturday.
The transition day will be Friday. Clouds have been moving in most of the day as we prepare for a slight chance for a stray shower overnight. Highs today will still be well into the 40s, but the trend to cool down will have begun.
Friday will be a more noticeable transition day as highs will be in the upper 30s. Cold air from the north and east will migrate into Oregon that will only allow the mercury to rise into the 30s. I expect middle to upper 30s Friday but only upper 20s and low 30s Saturday.
Saturday is the coldest day of the forecast period. An upper level low drives deep into Nevada and Central California and will be responsible for providing much colder air to Central Oregon. The flow of air will arrive from the northeast, where the bitter arctic air had established itself. That northeast flow will persist into Sunday and the cold pattern will remain until Monday.
Please stay safe.
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