A strong marine layer of clouds will hang around through late morning or early afternoon on Monday helping to cool things a bit from Sunday's temperatures in the mid 80s.
Forecasters with the National Weather Service see a stronger onshore pressure gradient from about Salem north than to the south, and predict it will take longer for clouds to clear in the Portland area than south of the Salem area. Portland's high on Monday will be 78 degrees.
Beginning July 4 and heading into the rest of the week, the Northwest region will come under a broad south to southwesterly flow aloft with pressure gradients remaining well off the coast. The result will be fewer morning clouds and warmer temperatures into midweek. Both Tuesday and Wednesday look mostly clear with highs in the mid-to-high 80s.
The one exception to the continued heating will be the Oregon Coast. Forecasters see some of that marine air continuing to linger along the coastal area with temperature remaining in the low-to-mid 60s. If you need a break from all this sun, the beach is your best bet for most of the week.