112 FXUS66 KPQR 031012 AFDPQR Area Forecast Discussion National Weather Service Portland OR 303 AM PDT Mon Sep 3 2018 .SYNOPSIS...Warmer weather will return this week before a frontal storm system brings a decent chance for light rain and cooler temperatures late Friday or Saturday. && .SHORT TERM...Tonight through Thursday...Water vapor satellite imagery early this morning shows a rather distinct shortwave trough dropping southeastward into the Rocky Mountain states. Models have been suggesting this storm system would drag a weak front southeastward into our northern zones later this morning. However, satellite imagery suggests this feature is almost indiscernible at low levels given the lack of clouds associated with it. As a result, trimmed mentionable PoPs for this morning and may further do so in a couple more hours depending on satellite and radar trends. Temperatures for this afternoon were nudged upward a degree or two given the cloud cover may not be extensive as previously anticipated. Models are in good agreement shortwave ridging will shift eastward across the Pacific Northwest Tuesday and Wednesday. Thermal low pressure over northern California will shift northward into northwest Oregon and southwest Washington Tuesday and Wednesday, which should lead to warmer temperatures and plenty of sunshine. Would not be surprised to see a few inland sites flirt with 90F on Wednesday. As a shortwave trough slowly moves southeastward into the northeast Pacific and Pacific Northwest late in the work week, expect increasing southwesterly flow to overspread the region Wednesday night and Thursday. This should allow marine clouds to return to the coast and perhaps even inland. This should cool temperatures for inland locations a bit when compared to Wednesday, but these transition days have a tendency to not cool as much as modeled days in advance. /Neuman .LONG TERM...Thursday night through Monday...Models are in general agreement a shortwave trough over the northeast Pacific will push a front into the Pacific Northwest late Friday and early Saturday. This should bring a good chance for some light rain and cooler temperatures to the region. However, there still remain some notable differences between the individual operational runs that affect exact timing, coverage, duration and total rainfall amounts so kept PoPs in the chance category for now. Overall, it appears the bulk of the storm system will swing north of the region and rainfall amounts should remain rather light across our CWA. As we move into Sunday and Monday, models continue to diverge significantly with the latest GFS producing a warmer and dry scenario while the latest EC suggests a more substantial frontal storm system could bring wetting rains to a sizable portion of the forecast area. Given the uncertainty among the models generally kept PoPs near climatology with the highest PoPs centered across our northern zones where even northward shift in the EC solution could still result in some rain Sunday or Monday. /Neuman && .AVIATION...Shallow stratus layer mainly over the coastal waters but ashore north of KTMK bringing IFR cigs. A weak front was to move into the area this morning to bring more widespread low MVFR to IFR cigs along with some rain. This front has all but dissipated so expect less clouds and pcpn. MVFR cigs should fill in up the Columbia River to the KPDX area shortly after sunrise, then dissipate by midday. Do not see much in the way cigs in the valley, but may have MVFR cigs along the Cascade foothills for a few hours this morning. Otherwise VFR inland and the coast this afternoon and evening. Stratus should return to the coast in the evening but not push very far inland. KPDX AND APPROACHES...VFR should give way to MVFR cigs 1000-1500 feet 14Z-18Z, then return to VFR. Breezy NW winds will pick up again Mon afternoon and evening. /mh Pyle && .MARINE...A fairly persistent pattern is expected for the next several days. High pressure will reside over the NE Pac, with thermal low pressure over the northern CA and southern OR coast. This will result in periodically gusty N winds over the coastal waters, particularly over PZZ255/PZZ275. Gusts of 25 to 30 kt are, with the strongest winds during the afternoon and evening hours. The current Small Craft Advisory for winds for PZZ255/PZZ275 has been extended through Tue night. Will also need to watch for occasional gusts to 25 kt over PZZ250/PZZ270 this afternoon and evening, but at this time do not an advisory is warranted. Current models show much of PZZ250/PZZ270 should have gusts to 25 kt Tue and Tue night. The strongest winds should be beyond 5-10 NM at night and early morning, then reach the coastline in the afternoon and evening hours. Winds are expected to gradually subside for the latter half of the week. Seas are currently around 5 to 6 ft, but they will increase another 1 to 2 ft over the next few days in response to the gusty northerly winds. Seas will occasionally be steep due to the gusty northerly winds, but a persistent northwesterly swell around 9 to 11 seconds should prevent the need for a Small Craft Advisory for square seas. /mh /64 && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory for winds until 5 AM PDT Wednesday for Coastal Waters from Cascade Head OR to Florence OR out 60 NM. && $$ 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 CWA or forecast area.