Cooler Temperatures Spreading Across the West This Week

Parts of the western U.S. have experienced some of the hottest weather of the year in the last week, however, the peak summer like heat is about to be replaced with fall conditions in the days ahead. Here is a look at the cooldown that has already started across some areas of the West and when the rest can expect to see the plunge in the temperatures.

Heat Wave Across the West Coming to an End

While the noticeable drop in the temperatures will be a relief to residents of the West, the change in the weather will also come along with an increase in the threat of flooding and wildfire danger. The cooler temperatures will be quite dramatic when compared to the sizzling readings to start the month of September.

How hot was it? Seattle saw the mercury hit 90 degrees late last week, the warmest that it has been in the Emerald City since mid-July. Portland recorded readings that inched up over the century mark, roughly 20 degrees warmer than the historical average for this time of the year.

It was also scorching hot throughout the bulk of California. For example, Fresno saw several days with temperatures in the triple digits. It has also been well into the 90s in normally temperate Los Angeles.

Forecasters are predicting that the temperatures will be trimmed throughout the week as an influx of cooler air takes over the western third of the country. A southward dip in the jet stream will be responsible for sending cooler air spilling to the south.

Where to Expect the Temperatures to Land

The Pacific Northwest is already experiencing the cooldown. Seattle topped out with readings in the low 70s on Monday with temperatures forecast to hover in the upper 60s for highs on Tuesday. The cool weather will hang on through the week as a shot of moisture also moves into the Northwest on Wednesday. For example, Seattle is expecting rain showers and highs in the low 60s by the middle of the week.

Heading to the south into Portland, the city just over the border from Washington in Oregon is forecast to drop from highs in the mid 70s on Tuesday to readings that max out at about 65. You have to go back nearly a month to find the last time that it has been this cool in Portland. The Rose City will also be under the threat of scattered rain showers on Wednesday.

Overall, temperatures will land about 15 to 20 degrees below the historical average for much of the Northwest. The temperatures will start to rebound by the end of the week in this region, however, readings will still remain just a bit below the norm for the middle of September throughout the weekend.

You can also expect cooler weather in the Central Valley of California. Both Sacramento and Fresno will enjoy temperatures that fall as much as 20 degrees from the weekend highs by Tuesday. This will translate to a high in the mid 80s on Tuesday and Wednesday in Sacramento. An increase in the cloud cover will help to make it feel even cooler in the capital city.

The same southward dip in the jet stream will continue to track farther to the east as the week progresses. This movement will result in cooler weather for the interior West as the focus of the intense heat lands in the Plains states.