October Will End With Widespread Cold From the Rockies to Plains and Upper Midwest

Jonathan Erdman
Published: October 23, 2019

October will wrap up with more persistent cold in a sizable part of the Rockies, Plains and upper Midwest from a significant change in the jet stream pattern beginning later this week.

Over the past couple of weeks, we've seen some significant cold fronts sweep through the Plains and East, bringing an end to a record early-October heat wave, ushering in some first frosts and freezes of the season while spawning an intense Northern Plains blizzard and Northeast bomb cyclone.

In the wake of these systems, the cold air in the Midwest, South and East has generally been short-lived, lasting one or two days before a warmup ensued.

(MORE: Current Temperatures | 24-Hour Temperature Change

By later this week, however, a change in the pattern should allow cold air to not only plunge deep into the U.S., but also lock in place for a while.

The overall jet stream pattern setting up for the end of October, funneling colder air into the Rockies, Plains and Midwest.

Computer forecast models suggest two northward bulges of the jet stream are expected to form. One of these near Greenland is what meteorologists call a "Greenland block." The other may bulge north just off the West Coast.

Between these two northward bulges, the jet stream has to plunge south. When it does, the cold air trap door is wide open into the U.S.

But it's the persistence of those blocking northward jet stream bulges that typically allows colder air to last longer than a few days.

That's precisely what the forecast models are suggesting. This colder weather pattern, once in place later in the week, could last through Halloween, or perhaps the first weekend of November, over a large part of the nation.

(MAPS: 10-Day U.S. Forecast High and Low Temperatures

The highest confidence of persistent cold to end October is from parts of the Rockies to the Plains and upper Midwest.

Stubborn high pressure over the western Atlantic will likely keep the coldest air from reaching much of the East Coast. Parts of the Southeast – Florida and southeastern Georgia, in particular – may be among the few spots to escape this persistent cold near month's end.


NOAA Extended Temperature Outlook

Low temperatures by early next week are forecast to be 10 to 30 degrees below average for late October from the Great Basin and the Rockies to the Plains and upper Midwest.

Morning low temperatures in the 20s could spread from much of the Plains to the upper Mississippi Valley during the first half of next week. Lows in the teens and single digits might grip parts of the Rockies.


Forecast Morning Lows Early Next Week

The first half of October was among the five coldest on record in much of the Northwest, northern Rockies and parts of the Northern Plains, according to the Southeast Regional Climate Center.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.


The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.