551 FXUS66 KPQR 111706 CCA AFDPQR Area Forecast Discussion National Weather Service Portland OR 902 AM PST Mon Nov 11 2019 .SYNOPSIS...Drier weather is expected today with high pressure back over the Pac NW. Offshore flow will lead to above normal temperatures and less cloud cover. Another weak cold front is likely to clip the region Tuesday with some rain, mostly north. The latter half of the week may see additional frontal systems moving through for a return to more seasonable wet weather. && .SHORT TERM...Today through Wednesday...High pressure over eastern Washington/Oregon will maintain increasing offshore flow today. Area of fog and low stratus still to the north of Portland/Vancouver, and to south of Portland. But, offshore winds have brought somewhat drier air to the low levels into the Willamette Valley. This drier air leading to clearing skies to in the Portland/Vancouver metro, and to the south to the west of I5 as far south as Albany. Low clouds and fog still hugging areas east of I5 to south of Aurora, with most widespread fog/stratus covering the south Willamette Valley southward through Cottage Grove into the Umpqua Valley. Coast has best conditions, under mostly clear skies, with just variable high clouds. Offshore pressure gradient across the Columbia Gorge, from The Dalles to Troutdale, near 7.0 mb offshore at 9 am. This will maintain breezy east winds in the western Columbia Gorge, with gusts 35 to 45 mph but locally to 55 mph such as at Crown Point. Closer to the metro, gusts generally 20 to 35 mph, with strongest at Troutdale. Winds will gradually east tonight into Tue. Models have been fairly consistent in showing a short wave topping the upper ridge late tonight and Tuesday, allowing a cold front to push east across the forecast area Tuesday. Not unlike the previous front from late last week, some tropical moisture has been entrained into this system as seen in satellite imagery, and GFS continues to suggest precipitable water values on the order of 1.0" to 1.2" as the front moves through Tuesday. Best dynamics will be across the north part of the forecast area, with chances for rain ranging from categorical in the north to slight chances in the south. After slightly above normal temperatures for many areas today, clouds and precipitation will bring temperatures back to near or even a little below normal during the daytime Tuesday. The clouds will also tend to limit diurnal temperature swings Tuesday night, keeping the low temperatures above normal. By Wednesday models are quick to restrengthen the upper ridge over the region, allowing an offshore flow to redevelop. Strong subsidence along with initially moist low levels suggest plenty of fog or low clouds are likely to develop Tuesday night and persist into Wednesday morning. /Rockellson .LONG TERM...No Changes. Previous discussion follows...Wednesday night through Sunday...Upper level ridging builds back across the forecast area Wednesday night and Thursday, though not quite as strong as the ridge building in tonight/Monday. Forecast models also suggest some baggy troughing somewhere in the vicinity of the California coast Thursday, which appears likely to encourage split flow with the next front expected for Friday. This seems to suggest Friday's front will be fairly weak for this time of year. Longer range guidance suggests the pattern should become more active either during the weekend or the following week, which makes sense considering the active phase of the MJO is currently entering the West Pacific. This can often be a sign of a pattern change toward more active weather 7 to 10 days out as the north Pacific jet strengthens and becomes more zonal. Weagle && .AVIATION...Westerly flow aloft will maintain variable high clouds across the region today into tonight. Areas of IFR stratus remain in the lower Columbia River between Clatskanie and Vancouver, with IFR stratus/fog also along to east of I5 from Aurora southward to Albany, then more extensive stratus on to south through Eugene and Cottage Grove. Tops generally 1000 to 1500 feet, so think should burn out for most areas between 19Z and 21Z. Then, VFR through tonight. Moderate offshore pressure gradient of 7.0 mb across the Columbia Gorge, with east winds 25 to 40 kt in that area. East winds less degree continue along the coast, inland areas and over the higher terrain. Gradients weaken somewhat tonight, and likely to get areas of fog/stratus reforming to south of Salem as well as the Cowlitz Valley after 05Z tonight. KPDX AND APPROACHES...Cross-Gorge pres gradient now near 7.0 mb offshore, which keeps easterly winds 15 to 25 kt at KTTD, and 10 to 15 kt across rest of PDX ops area today. But, still have lee side trough along I205, which is keeping winds at KPDX and downstream to KVUO and KSPB as light westerly. East winds staying just above KPDX. This pattern will hold til 18Z, then will see east wind surface at KPDX as trough shifts to west a bit more. /Rockey && .MARINE...Surface high will gradually build over the inland Pac NW, with increasing east to northeast winds across the coastal waters into Mon. Think most gusts stay in the 5 to 15 kt range at most, but could see a few gusts 20 to 25 kt in gaps of the coastal terrain and near larger bays later today. Winds relax on Tue and gradient weakens thanks to the warm front slowly approaching and lifting to the north of the region. Southerly winds stay in the 10 to 15 kt, with 4 to 6 ft seas. Models continue to show another front arriving late Thu. But, models have had inconsistency in strength and timing of the front. Will see a boost in westerly swell behind the front, with swell getting up to 10 to 13 ft. Another front will arrive later next Sat into Sun, with stronger potential for 25 to 35 kt winds and building seas. /mh - Rockey/Muessle && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Air Stagnation Advisory until noon PST Tuesday for Cascade Foothills in Lane County-Central Columbia River Gorge- Central Willamette Valley-Greater Portland Metro Area- Lower Columbia-Northern Oregon Cascade Foothills-South Willamette Valley-Upper Hood River Valley-Western Columbia River Gorge. WA...Air Stagnation Advisory until noon PST Tuesday for Central Columbia River Gorge-Greater Vancouver Area-I-5 Corridor in Cowlitz County-South Washington Cascade Foothills- Western Columbia River Gorge. 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.