October Will End Cold in the Rockies, Plains and Upper Midwest

Cascade Snow To Be Measured In Feet

The rest of October will be much colder over the Rockies, Plains and upper Midwest as another strong cold front will deliver temperatures more typical of late November or December to some of those areas.

A pair of bulges in the jet stream is setting this colder pattern into motion.

One of these northward bulges of the jet near Greenland is what meteorologists call a "Greenland block." Another will bulge north just off the West Coast, diverting the jet into Alaska and northwestern Canada.

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.

When these blocking northward jet stream bulges are persistent, it typically allows colder air to last longer than a few days. In this case, this colder pattern could last through the first weekend of November over a sizable part of the country.

(MORE: Current Temperatures | 24-Hour Temperature Change)

A cold front moved through parts of the western and central U.S. midweek and a second, stronger cold front will sweep through the Rockies, Northern Plains and Northwest Saturday, then plunge into the Great Basin and Plains Sunday. It will eventually work its way into the Desert Southwest and Mississippi Valley next week.

The East Coast, however, may not see colder air until after Halloween.

Forecast High-lights

Behind the cold front this weekend, expect highs generally in the 20s and 30s in the northern and central Rockies, 30s and 40s in the Northern Plains and upper Midwest and 40s or 50s in the northern Great Basin and Central Plains. Generally speaking, these high temperatures are more typical of late November or December.

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

Denver's high on Tuesday could be around 40 degrees below average.

Frigid Low Temperatures Expected

Lows in the single digits and teens will be more widespread in the northern and central Rockies during the first half of next week. Temperatures will drop into the teens and 20s in the northern Great Basin and Northern Plains and into the 30s in Oklahoma and west-central Texas.

These lows will be 20-30 degrees below average for late October.

Some daily record lows could be set in the Great Basin and Rockies early next week.

But that's not all folks, as temperatures will drop even further by midweek in the central and northern Rockies. A few spots could see morning lows as much as 40 degrees below average next Wednesday. This could bring temperatures below zero in parts of Wyoming, Montana, and Idaho.

Some snow will also accompany this air beginning this weekend in the Rockies. Snow may also extend into parts of the Plains and upper Midwest early next week.

(MAP: 48-Hour Snowfall Forecast)

How Long Will It Last?

As we alluded to earlier, the cold air will take its time oozing into the East next week, possibly not arriving until after Halloween.

Due to the persistence of this jet stream pattern, with the exception of the Florida Peninsula, this generally colder than average temperature regime over much of the country may then last into the first full week of November, according to the latest computer forecast models.

(MORE: 2019-20 Winter Outlook)

Midweek Cold Front

The first cold front moved through the Plains midweek.

Snow accompanied this first front late Wednesday into Thursday along the Front Range of the Rockies and adjacent High Plains, including the Denver metro area and parts of the Texas Panhandle.

A few inches of snow piled up in Denver, but totals were much higher just west of the city. Golden, Colorado, picked up 12.5 inches of snow through Thursday morning.

Thundersnow was reported Thursday in Amarillo, Texas. Snowfall totals in the Texas Panhandle ranged generally from 1 to 4 inches and up to 9 inches accumulated near Pampa and Stinnett.

Oklahoma set a new October 24-hour snowfall record when a total of 13 inches of snow was measured near Arnett, Oklahoma on Friday morning.

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