Changes Ahead: Northwest Cools Off, Heat Returns to Midwest, East Briefly Dries Out

World's First Chief Heat Officer's Tips

A brief change in weather conditions is taking shape from the Northwest to the Midwest and the East as the jet stream takes on a new configuration.

Since last week, the jet stream pattern has been unusual for midsummer, set up in a north-to-south fashion east of the Rockies when it typically flows in a flatter west-to-east pattern near the Canadian border. This has brought near-record heat to the Northwest, below-average temperatures to the Midwest and locally heavy rain and flooding to the East.

This weather pattern is beginning to shift with the jet stream bulging northward over the East and dipping a bit southward in the Northwest. That will allow cooler air to infiltrate the Northwest late this week as heat builds over the Midwest into this weekend, and the East will briefly dry out over the weekend and into early next week.

Northwest Cools Down

Changes arrived Thursday in the Pacific Northwest, where Seattle was stuck in the 60s Thursday afternoon. This change comes after recording 16 days at or above 85 degrees in July, tied with August 1967 for the most on record in any month, vaulting July 2018 to the second-warmest July on record in the Emerald City.

Below-average conditions will expand into the interior Northwest through the weekend, holding temperatures mainly in the comfortable 70s and lower 80s.

In addition, some rain showers are even possible in Washington on Saturday in what is normally the region's dry season. Through Friday, Seattle picked up 0.05 inches of rain, its first since July 7.

Highs will generally be 5 to 15 degrees above average this weekend, especially across the Great Lakes region. The rest of the Midwest will likely see near-average temperatures. This translates to highs in the upper 80s and lower 90s.

The above-average warmth will reach the Northeast by Sunday, but the bigger story for much of the East will be a briefly drier weather pattern.​​​​​​

The most persistent showers and thunderstorms should exit the Eastern Seaboard Saturday, ending the soggy pattern that's in place this week.

(MORE: Flood Threat Continues in the East This Week)

Scattered showers and thunderstorms remain possible in the East Sunday and Monday, but nothing to the extent of what has occurred over the past two weeks. However, rain chances may increase again by the middle of next week as a cold front approaches the region.