Satellite images: Developing 'Pineapple Express' hits Pacific Northwest

PORTLAND, Ore. (KOIN) — Satellite imagery provided by NASA gives a clear picture of the atmospheric river actively flowing into the Pacific Northwest, supplying the region with warmer temperatures and inches of rain.

The atmospheric river stems from a storm churning in the Gulf of Alaska, which is drawing subtropical moisture directly from Hawaii to Oregon and the rest of the Pacific Northwest. This weather phenomenon is commonly referred to as the “Pineapple Express.”

KOIN 6 Meteorologist Josh Cozart said that the warmer, subtropical moisture from Hawaii helped break a temperature record in Portland Monday.

“Portland actually broke a record for warmest Dec. 4 on record,” Cozart said. “Portland climbed to 65 degrees, breaking the old record of 59 last set in 1970.”

While the storm’s initial blast delivered warmer weather, Cozart said that the atmospheric river will bring cooler temperatures by Thursday as the slow-moving storm whisks colder air into the mix.

“The tail, or river, attached to the cinnamon roll shape is also a cold front that will eventually help work cooler temperatures back into the region,” Cozart said. "Right now, the system is bringing in warmer conditions, but as it moves east, it will start to pull colder air into the area from Alaska."

The record temperatures have dampened Mount Hood ski slopes with rain as snowfall levels are forecast to remain above 9,000 feet through Wednesday. While Mount Hood slopes remain closed, the Mount Hood Meadows ski resort told KOIN 6 that falling temperatures may allow the ski park to open for the season on Dec. 8.