20-degree temperature drop expected around Portland this weekend

PORTLAND, Ore. (KOIN) -- Another round of summer heat will build around Portland on Saturday as the Pacific Northwest prepares for a 20-degree temperature drop on Sunday.

Toasty temperatures continue Saturday for the first weekend of the summer season in western Oregon and Washington. Temperatures will climb into the upper 80s by the late afternoon and early evening hours on Saturday. This comes off the heals of 90-degree heat seen along the Willamette Valley for the first few days of summer.

The summer heat will start to subside on Sunday as a weak front approaches the region. Temperatures will fall nearly 20 degrees from Saturday's afternoon highs to Sunday's mid-70s that are in the forecast. The increase in cloud coverage could bring a stray rain shower or two to the region. However, no accumulative rain is expected.

The lack of rain will keep the wildfire threat high for the start of the weekend. Hot and dry conditions will push Oregon's wildfire weather threat to moderate levels. Less of a wildfire threat is expected with cooler temperatures on Sunday.

Rain-free skies will also keep grass pollen high through the Willamette Valley through much of next week. Pollen counts aren't expected to start to decrease across the Pacific Northwest until the start of July.

Summer-like heat will start to build again next week. Afternoon highs will climb back into the mid-80s by Tuesday before another weak system brings temperatures back to near-normal conditions for the end of June.