SYNOPSIS
High pressure will maintain dry weather with temperatures more typical of late September through the start of next week. A weak front will bring a chance of showers Sunday into Monday for northern parts of the forecast area, with a slightly stronger front during the middle of next week. Warm, dry weather likely to return for the latter part of next week.

SHORT TERM
Tonight through Saturday night...High pressure will continue to be the dominant synoptic feature over the Pacific NW through the weekend. This will maintain variable onshore flow and result in clouds returning overnight and scouring out each afternoon/evening. Overall, expect a slight warming trend though the latter part of this week and into the weekend as the aforementioned upper level high slowly drifts inland. This scenario will also result in the development of a thermally induced trough. Which looks to set up along the southern Oregon coast and slowly stretch northward through Saturday. This will also aid in maintaining northwesterly flow, which will result in breezy west/northwest winds for Friday, especially over the higher terrain and through the middle and eastern end of the Columbia Gorge. For the start of the weekend expect less wind, less clouds and tad warmer conditions. Daytime highs will generally be around seasonal norms or just a touch higher. So, expect daytime highs through Saturday to be in the mid to upper 70s across the inland portions of the forecast area and temperatures along the coast running about 10 degrees cooler IE the mid to upper 60s. /42

LONG TERM
Sunday through Thursday...Sunday looks to feature a fairly zonal upper level flow regime across the Pacific Northwest, maintaining dry and seasonable weather with inland high temperatures in the mid to upper 70s. A weak upper level disturbance skirting the Canadian border will bring a slight chance of rain across southwest Washington and far northwest Oregon Sunday evening into Sunday night, but expect most locations to ultimately remain dry. Medium range guidance continues to converge on a warmer and drier solution for the start of next week, with ensemble clusters and 12z deterministic models both showing good agreement on an upper level ridge building over the Pacific Northwest on Monday and shifting inland on Tuesday. This will bring well above normal temperatures to the area on Tuesday as highs climb into the mid to perhaps upper 80s in the interior valleys. The potential for temperatures higher than that appears rather minimal as latest probabilistic guidance gives only about a 10 percent chance to reach 90 degrees in the Portland area and closer to a 30 percent chance from Salem to Eugene. Any heat concerns look to be limited to just Tuesday as the ridge shifts east of the region and temperatures trend back down mid to late week. Guidance also depicts a short lived period of offshore flow developing late Monday into early Tuesday. Not overly concerned about east winds at this time given the progressive nature of the pattern and fairly modest offshore pressure gradients, but will be something worth keeping an eye on for those in the fire weather community as roughly half of European ensemble members depict wind gusts reaching 25 mph in the vicinity of the Columbia River Gorge late Monday into early Tuesday. Still some uncertainty beyond Tuesday as the ridge shifts east to the Rockies, with guidance remaining split on the strength and timing of an upper level trough arriving Wednesday into Thursday. NBM mean solution depicts temperatures moderating to near seasonal norms with chance to slight chance PoPs returning to coastal and northern parts of the area during the middle of the week. /CB



AVIATION
Upper level ridge with fairly dry northwest flow aloft persists tonight into Friday. Coastal stratus has begun to build north of Tillamook this evening and we'll likely see a similar repeat of stratus redevelopment after 12-13z inland terminals(40-70%), especially across northern parts of the forecast area around the Portland Metro area. Any low stratus dissipates by the afternoon. Generally expect north to northwest winds, increasing during the afternoon.

PDX APPROACHES...VFR expected with variable high clouds tonight.
There is around a 50-70% chance of MVFR CIGS redevelopment between ~13-19z Friday followed by a return to VFR. Expect northwest winds to around 6-8 kt Thursday afternoon. -Schuldt/DH

MARINE
Not much change as high pressure persists over the coastal waters, resulting in a summer like pattern of northerly winds today through Friday. As the thermal trough strengthens over the southern Oregon coast, winds will likely gust up to 20-25 kt over the outer coastal waters this afternoon through tonight. Also expect winds to gust up to 25 kt across the inner coastal waters south of Cape Foulweather through this evening. The Small Craft Advisory continues to cover the increased winds and choppy seas expected through tonight. Pressure gradients across the coastal waters weaken somewhat over the weekend, likely resulting in a decrease in north to northwest wind speeds.

A persistent northwest swell will maintain seas around 6 to 8 ft through Friday, with a dominant period of around 8 to 10 seconds.
Seas then expected to subside back to around 5 to 6 ft for the weekend. /DH

PQR WATCHES/WARNINGS/ADVISORIES
OR...None.
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ253.
Small Craft Advisory until 5 AM PDT Friday for PZZ271>273.