Why Much of the Nation's Weather Has Been So Quiet Recently: Blame the Stormy North Pacific

Jonathan Belles
Published: November 5,2016
Jumping in brightly-colored leaves, bundling up in the first frost and whisking away the first white precipitation of the season. There are a few things missing from this list of familiar things in fall: wild swings in temperature and growing storm systems.
Since mid-October, weather across the Lower 48 has been largely pin-drop quiet.
(MORE: Some Cities Haven't Seen Rain Since September)

What's the Reason for the Peaceful Weather?

The calendar may say it is autumn, but the jet stream is still behaving as if the sun didn't pass south of the equator. During the summer doldrums, weather systems typically ride well north of the border, and at a lesser intensity. We are seeing some of the very same large-scale puzzle pieces that we typically see during those warmer months.
Over the last few weeks, the jet stream has been largely stuck in place north of the Plains states, bringing dry, warm conditions to most of the United States.

Ingredients for a quiet few weeks in the Continental United States

When a strong ridge of high pressure is in place, usually there will be strong troughs, or dips in the jet stream, of low pressure on either side. Contrary to what most of us are seeing, the jet stream has been very energetic over the northern Pacific Ocean.

Typical location of the Aleutian Low and wind flow around it in the winter.

At the surface, the Aleutian Low, named for its typical location in the Aleutian archipelago in southwestern Alaska, is a semi-permanent feature that develops in the typically colder months.
This is not a player that's there all the time in the winter, but it tends to be near southern Alaska more often than not.
This feature, although slightly displaced from the Aleutian Islands at times, will continue to drive periods of heavy precipitation and gusty winds in southern Alaska, western Canada and the Pacific Northwest over the next week or so.
In the Pacific, dips in the jet stream aloft have been fairly common recently. This has resulted in higher than normal rainfall in the Pacific Northwest. Strong storms battered the coast from Oregon to British Columbia in October, and these storms continue to bring enhanced precipitation.

This isn't to say cold fronts haven't tried to cross the country, as there have been a few that have made it to the Gulf Coast. Those weather makers that have been able to break the ridge have mostly been silent, dehydrated warriors.
Subtle jet stream dips in the Midwest and Northeast over the last week have also led to rain delays at the World Series and a few early season snowstorms in the Northeast's higher elevations.

When Will Bigger Weather Systems Return to the Lower 48?

With a persistent pattern like this one, it may take one large storm to dislodge the doldrums from the Great Plains and South.
There are a few such systems that can do that this time of year: a late-season typhoon that recurves in the far western Pacific, and a strong early-season winter storm that comes from Asia and moves toward Alaska or Canada from the northwest.
(MORE: Four Things to Know About Next Week's Weather)
There is another hope for rainfall in the southern tier of the country. Some weather forecast models show a strengthening of the subtropical jet stream in about a week, but exactly how much rainfall results from that remains a big question.

MORE: Our National Parks