PORTLAND, Ore. (KOIN) — If you’re a native Oregonian or Washingtonian, you know that May and June can be a bouncy month or two as far as transitioning to summer.
This week is a good example of that, with 80-degree temperatures over the Starlight Parade weekend to lower 60s and showers to wrap up this week.
The reason for the transition to cool and shower weather? This trough dropping down from the north allowing for cool Canadian air and the triggering mechanisms for some showers, especially on Friday.
Well we are likely going to go for that roller coaster ride of up and down and back around next week as a fairly strong ridge of high pressure starts to build around Sunday, June 9 and that should last for 3 to 4 days before it breaks down again.
What does this mean? It means that we are going to skyrocket from the cool and showery weather to probably upper 80s to near 90s by Tuesday and Wednesday of next week. Now, we’ve already had some days in the upper 80s this spring, but as we start to approach mid-June, that likelihood for 90-degree temperatures becomes greater.
Although there could be some slight changes by then, the overall trend between multiple weather models is trending towards the summer heat. Which, by the way, Summer officially begins Friday, June 21.
In the graphic below, which is the 500mb temperature graphic, you can see a large hill in the shade of orange over the PNW, that is what we call a ridge of high pressure. This will help promote warmer weather and dry conditions for the PNW.
In meteorology, according to the American Meteorological Society, a ridge is referred to as “an elongated area of relatively high atmospheric pressure, almost always associated with and most clearly identified as an area of maximum anticyclonic curvature of wind flow.” You can really sense that here as those lines stretch up in an elongated fashion.
As far as the wind flow goes, anticyclonic curvature is when the wind moves in a clockwise motion around the area of high pressure. This motion, if the high pressure is set up correctly, can also promote offshore wind that helps warm up locations in The Willamette Valley and The Oregon Coast. Part of the reasoning for that is drainage wind that comes down the mountains and creates warmer and more stable conditions.
With all of that being said, take a gaze at our 7-day forecast that has been put together from the KOIN 6 Meteorologists, we are also trending our temperatures towards warmer summer weather.