794 FXUS66 KPQR 282138 AFDPQR Area Forecast Discussion National Weather Service Portland OR 237 PM PDT Mon Aug 28 2017 .SYNOPSIS...Hot weather continues today as strong upper level high pressure resides over the Pac NW. A surface thermal trough will push east of the Cascades tonight and Tue, bringing onshore flow and slightly cooler temperatures. Wed and Thu are cooler yet as an upper level trough moves through the region and onshore flow strengthens. Then warmer temperatures return for Fri into next weekend. && .SHORT TERM...Today through Wednesday...Wildfire smoke appears to have subdued heating a few degrees below guidance as expected. Still expect many locations to top out in the mid to possibly upper 90s, but any sites reaching 100 degrees appears unlikely at this time. Will leave the expiration time of the heat advisory at 8pm this evening as temperatures should be below 90 degrees everywhere by that time. The other major story is the wildfire smoke which has overtaken the entire area. The worst surface smoke conditions are south of Salem where air quality has decreased to unhealthy. Therefore, the Lane Regional Air Protection Agency decided to issue an air quality alert through 4pm tomorrow. Increasing onshore flow should clean out most of the smoke from the area by tomorrow afternoon/evening, especially for the north Willamette Valley as winds become more westerly. Temperatures will cool through mid week as troughing moves into the area and onshore flow strengthens. Unfortunately, this will be short lived as a return to the hot, dry weather returns into the long term period. /Bentley .LONG TERM...Thursday night through Monday...A trough later this week will bring temperatures back up a couple degrees through the weekend and into early next week. Still no rain in site. -Bishop && .AVIATION...Expect predominately VFR conditions in the interior the next 24 hours. However, areas of MVFR cigs and vsbys due to smoke are possible, especially south of KUAO. Light surface winds may exacerbate flight conditions in the southern interior and preclude smoke from leaving the area once it settles in. Areas north of KUAO may see brief periods of reduced vsbys through late this evening as smoke aloft mixes to the surface. Conditions look to improve Tue as onshore flow strengthens. Conditions at the coast remain mostly VFR this afternoon, with occasional smoke impacting the terminals. A southerly wind reversal will likely bring IFR/LIFR stratus to the coast later today and tonight from south to north. Expect reduced flight conditions to continue at the coast into Tue with some improvement expected Tue afternoon/evening. KPDX AND APPROACHES...Predominately VFR the next 24 hours. Brief periods of reduced vsbys due to smoke possible through late this evening. /64 && .MARINE...Winds over the central waters have become southerly this afternoon. Expect these southerly winds to continue to spread north this afternoon and tonight, with gusts to 20 kt possible tonight and early Tuesday. A weak front moving across the waters Wednesday and Wednesday night will bring another batch of southerly winds to the coastal waters, but will likely stay below advisory criteria. Winds will turn northerly and likely exceed 20 kt late Thursday and continue into the weekend. A northwesterly swell between 10 to 12 seconds will continue for a few days. Seas are currently around 6 ft this afternoon, but will fall to around 4 to 5 ft tonight and remain in this range through most of the week. Seas may climb to 6 to 8 ft late this week and into this weekend with the increasing northerly winds. /64/pt && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Red Flag Warning until 8 PM PDT this evening for Central Oregon Cascade Foothills-Mt. Hood National Forest West of Cascade Crest-North Oregon Cascade Foothills-Willamette National Forest-Willamette Valley. Heat Advisory until 8 PM PDT this evening for Cascade Foothills in Lane County-Central Coast Range of Western Oregon- Central Columbia River Gorge-Central Willamette Valley- Coast Range of Northwest Oregon-Greater Portland Metro Area-Lower Columbia-Northern Oregon Cascade Foothills- South Willamette Valley-Upper Hood River Valley-Western Columbia River Gorge. WA...Red Flag Warning until 8 PM PDT this evening for Clark County Lowlands-Eastern Gifford Pinchot National Forest Mt Adams Ranger District-Extreme South Washington Cascades and Foothills. Heat Advisory until 8 PM PDT this evening for Central Columbia River Gorge-Greater Vancouver Area-I-5 Corridor in Cowlitz County-South Washington Cascade Foothills-Western Columbia River Gorge-Willapa Hills. PZ...None. && $$ Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland This discussion is for Northwest Oregon and Southwest Washington from the Cascade crest to 60 nautical miles offshore. This area is commonly referred to as the forecast area.