'Omega Block' pattern arrives this weekend. Here's what it means for Portland
PORTLAND, Ore. (KOIN) — Sunny and dry conditions will prevail across the Pacific Northwest this weekend with blazing blue skies and no rain to worry about. It's all thanks to an upper-level high-pressure pattern called the "Omega Block."
This pattern comes with the name because the jet stream is snaking over the Pacific Ocean in such a way that it resembles the Greek letter "Ω" or omega.
An amplified area of high-pressure forms in the center of this pattern, creating the "ridge." Meanwhile, two areas of low pressure are on each side, which are called "troughs."
The weather within the ridge tends to stay calm and dry. The jet stream essentially "blocks" surface weather systems from flowing into the region. This can lead to a sunny weather pattern with clear skies and frigid overnight temps. The blocking high-pressure pattern can also anchor into place for days at a time, leading to extended periods with little change in the forecast.
When these high patterns happen at other times in the year, it can also lead to heatwaves, droughts, and surface air pollution. Inside of the troughs, areas tend to experience unsettled weather with cooler temps and more precipitation.
Portland's Weather Forecast
This "Omega Block" pattern will keep dry conditions in place likely through Wednesday of next week.
Forecasts then show an upper-level trough of low pressure shifting into the region to bring back wet conditions heading into the first weekend of February.
So, enjoy the weekend if you can. This will be one for the books with very sunny afternoons, mild highs nearing the 50s, and frosty morning temps well-below freezing.
Stay with the KOIN 6 Weather Team for the latest on the forecast across the Pacific Northwest.