At a Glance

A brief period of above-average temperatures returned to the central and eastern U.S. earlier this week.Now, a pattern change is allowing arctic air to surge into parts of the U.S. to start February.

A weather pattern change is now ushering in another round of cold conditions to begin February in the central and eastern U.S., making the recent milder temperatures a distant memory.

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Warmer-than-average temperatures were experienced across the eastern half of the country for much of the last seven days, but thingsare about to change as a new cold front is plunging south and east across the U.S.

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Highs on Thursday were in the 10s and 20s across most of the northern tier of the United States, but for a few unlucky folks in the Upper Midwest, temperatures didn't make it out of the single digits from northeastern Montana to northern Michigan. This is just a sign of things to come.

Pattern Change Brings Colder Conditions

The upper-level pattern responsible for the upcoming temperature change will consist of the jet stream bulging northward over the eastern Pacific Ocean, which will result in a southward dip in the jet stream over parts of the central and eastern U.S.

The upper-level weather pattern is expected to consist of a northward bulge in the jet stream over the eastern Pacific Ocean and West Coast and a southward dip in the jet stream over parts of the East.

This pattern will bring dry and warmer-than-average conditions to the Southwest, which is not good news for the growing drought concerns.

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For parts of the central and eastern U.S., this will mean rounds of colder-than-average temperatures. However, the regions where temperatures will likely be the greatest below average will be the northern Plains and upper Midwest.

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Below-average temperatures will spread into the Ohio Valley, South and East Friday into Saturday. High temperatures will not reach the freezing mark, and lows will drop into the single digits and teens, in muchof the Ohio Valley and Northeast.

Temperatures in the East will then moderate on Sunday, ahead of the next low-pressure system.

The good news is that this next roundwill not be as cold as we saw earlier in January and at the end of December. The colder conditions are also not expected to reach as far south as the last Arctic blast.

The South will see chillier conditions, but most of Florida should see temperatures remain close to average for this time of year.

This pattern will also open the door for thechance for wintry precipitation at times into next week.

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In addition, another surge of Arctic air is expected to move into the northern Plains and northern Rockies by the start of this weekend. Areas from theMidwest into the interior Northeast may be impacted by this next cold blast into the first full week of February.

Lows on Sunday morning will be well-below average from central Montana through the Dakotas and into Minnesota, where temperatures will plummet to the teens and 20s below zero. It will remain very chilly throughout the day with highs only topping out in the single digits for much of this area.

On Monday, highs will be in the single digits and teens from the northern Plains into much of the Great Lakes region. Low temperatures here will drop into the single digits above and below zero through early next week.