PORTLAND, Ore. (KOIN) – We are setting up for a sunny day in Portland, but we have to get through some patchy fog in the morning first.
High pressure is moving in and that is going to clear things out, but it will lead to cooling overnight. With some moisture on the ground and the radiational cooling, fog is going to form. Our visibility forecast is projecting many locations under a mile early tomorrow morning. More of an issue to the south where the wind will be blocked. Just be prepared for some fog to start the day, but it should dissipate through the morning and turn to sunshine.
We should start the week a few degrees above average with highs in the lower 50s. We’ve been cranking most of the month and our time is likely up with colder air set to arrive by the weekend. Temperatures quickly go from above average to below average by the end of the week. You’ll notice it more in the overnight and morning hours when lows drop to about freezing. This is going to be colder air pushing in from Canada through the course of the next 10 days.
The weather pattern will help show our first drop of cold air Thursday into Friday. The snow levels finally return to below pass level at this time, which means we generate some more snow for the bases of the ski resorts. This will also slow down travel again, so be prepared if you’re traveling late next week. We have a second surge of cold air by the weekend, which should take our high temperatures down even further. For now we will call for the lower 40s, but we will have to watch the forecast as it’s possible we have some upper 30s out there.
Observed low temperatures have been much warmer than we would typically see in January. A lot of mornings in the lower to mid 40s. We will drop back to the 30s most mornings this week. You can see that the normal low is 36 and we’ve only fallen below that mark twice in the last two weeks. There is a good chance that we find our low temperature at normal or below by Tuesday morning.
As far as rain goes? We won’t worry about that for the first 3 days of the week. Rain does move in on Thursday, with a few spotty showers for the weekend. Rain jackets aren’t necessary today and won’t be of much use Tuesday either. With well over our monthly average of rain, we could use a few dry days to let the rivers fall back and the ground to find recover.