Mild Pacific air heads our way; temps within striking distance of 60° Friday. Fast-moving system brings Saturday morning rain, possible thunder

Watch the “PINEAPPLE EXPRESS” at work—a persistent flow of moisture into a region meteorologists describe as an “ATMOSPHERIC RIVER”

It’s been drenching the Pacific Northwest in recent days, producing record rainfalls and abnormally mild temperature. This flood of abnormally mild, moist Pacific air with origins in the equatorial Pacific south of the Hawaiian Islands thousands of miles southwest of the U.S. West Coast, that’s to bring Chicago unseasonably mild temps Thursday and Friday. This could include a near 60-degree high temp in portions of the Chicago area Friday.

What you see here is a multi-day GOES WEST weather satellite animation produced by the folks at CIRA-RAMBB at Colorado State. This “movie” illustrates how persistent and targeted the flow of deep atmospheric moisture into the Pacific Northwest has been. Wave after wave of precipitation sweeps in—the rain intensity amplified by the flow’s interaction with the West’s mountains which act to lift and cool the air to saturation. These rains really add up. Recent days have seen totals exceeding 8″ in the hardest hit locations.

CLIMATE NEXUS newsletter (12/6/2023) reports the following:

"Atmospheric River Pummels PNW: The Pacific Northwest is being pummeled by intense storms that have flooded communities and potentially left two people dead. An atmospheric river storm began hitting the region over the weekend and continued for the third straight day on Tuesday, dropping several inches of rain in parts of Washington, Oregon, and northern California. The body of an unidentified person was found in a creek outside of Portland, while another man was presumed swept away by another flooded creek. The Coast Guard also performed five rescues across the region. The town of Forks, the rainiest town in the lower 48, got more than double its previous rainfall record for December 4 after getting 3.8 inches of rain Monday. 

Climate change is amplifying the intensity of storms and amount of precipitation, thanks to warmer air being able to carry more moisture; climate change is also intensifying swings between extremely dry and extremely wet conditions in certain regions, a phenomenon known as “weather whiplash.”

This is a GOES WEST near full disc view of the stream of warm, moist area heading into the Pacific Northwest from the tropical Pacific. It’s this unseasonably mild air which is Chicago and Midwest-bound and expected to send daytime highs surging into the 50s Thursday and Friday.

WATCH AN ANIMATED VERSION OF THIS SATELLITE IMAGERY FROM CIRA/RAMBB at Colorado State here:

2023 now certain to be the warmest year globally says Deputy Director Dr. Sam Burgess of Europe’s Copernicus Climate Change Service over the term of instrument records dating back to 1850

Burgess minced no words in a Wednesday post on “X” saying, “We can now say this with complete certainty (barring an asteroid hitting in the final three weeks of 2023)“.

The Copernicus Climate Change Service is co-located at the European Centre for Medium Range Weather Forecasts and is funded by the European Union. They conduct groundbreaking climate research and analyses.

Burgess noted that 6 months of 2023 have set warm temp records as have two seasons this year.

Here’s a link to the full Copernicus Service’s release on the anomalous and record-breaking level of global warmth, which also notes the warm mean global ocean temp is also a record breaker: