### La Niña Predicted to Bring Cooler Winter and Increased Snowfall to Portland

PORTLAND, Ore. - The Climate Prediction Center of the National Oceanic and Atmospheric Administration (NOAA) has forecasted the emergence of a weak La Niña this fall, which is expected to continue into the winter. Historically, La Niña winters in Portland tend to be characterized by cooler temperatures, ample Cascade snowpack, and near-normal to above-normal rainfall in the valleys.

La Niña influences the flow pattern in a way that typically brings an active jet stream into the Pacific Northwest. This atmospheric setup is likely to provoke numerous weather systems that will deliver significant precipitation to the region. Although the current ENSO Cycle indicates a developing La Niña, there remains a possibility of a neutral pattern. Notably, strong and moderate La Niña winters tend to result in above-average precipitation during Portland's rainy season, while a weak La Niña often corresponds with drier conditions.

For winter enthusiasts, this forecast is promising, especially for Mount Hood and the Cascades. La Niña winters are known to support near-normal to above-average snowfall in the mountains, often resulting in some of the snowiest seasons at higher elevations in the Northwest.

In the valleys, particularly in Portland, temperatures during La Niña winters generally trend cooler than average. One significant factor contributing to these cooler conditions is an increased likelihood of Arctic blasts, which can lead to extended periods of freezing temperatures. This raises the probability of substantial snowfall, with more valley snow expected compared to ice, unlike the previous winter.

In summary, La Niña winters typically yield a robust mountain snowpack and cooler valley temperatures. Precipitation in the valley decreases with a weak La Niña but increases with a stronger one. The likelihood of valley snowfall also rises, including the chance of a significant snowstorm.