BRYAN, Texas — October is forecast to end on a cold note across a large part of the country as a large pattern change takes shape. This pattern change will take shape by the end of the week, forcing cold air out of Canada into United States.

Numerical guidance, which is referred to as "computer models" by meteorologists, is a tool meteorologists use to help determine the future state of the atmosphere (i.e. what will happen in your area tomorrow or in 5 days). This guidance is indicating a equatorial dip in the jet stream across the central United States as the Eastern Pacific Ridge and Greenland Block establish, creating a "buckle" of the jet stream. This will force the jet stream south, allowing cold air to readily flow into central parts of the country.

Late-October upper-level setup
Late-October upper-level setup
KAGS
Late-October surface setup: frequent cold fronts
Late-October surface setup: frequent cold fronts
KAGS

The Climate Prediction Center (CPC) has highlighted the majority of central & western parts of the country for moderate to high probabilities of below average temperatures for days 6 through 10.

Days 6 through 10 temperature outlook (CPC)
Days 6 through 10 temperature outlook (CPC)
KAGS

The CPC also has the same areas with moderate to high probabilities of below average temperatures for days 8 through 14, which will cross over from the end of October into the beginning of November.

Days 8 through 14 temperature outlook (CPC)
Days 8 through 14 temperature outlook (CPC)
KAGS