952 FXUS66 KPQR 150956 AAA AFDPQR Area Forecast Discussion National Weather Service Portland OR 256 AM PDT Mon Oct 15 2018 .SYNOPSIS...High pressure over the region will produce an extended stretch of mild days, cool nights and clear skies through the week. The high pressure looks to break down next week for a decent chance for rain. && .SHORT TERM...Today through Wednesday...A high amplitude upper ridge continues over the NE Pacific. Storm systems over the north Pacific are being steered northward along the periphery of the ridge. The ridge will flatten some over the next several days as a deep trough over eastern north America shifts east. While dry weather will remain with us, the low level offshore flow will weaken. This will result in more widespread valley lows in the 30s since winds will ease. But with the dry air mass - dewpoints in the mid 20s to mid 30s - in place and shallow inversions expect lowland highs in the 60s to low 70s. Given growing season for most of our valley locations typically holds out until Oct 20th or Nov 1st depending on the zone there is a a Freeze Warning through early this morning for the central and southern Willamette Valley and the Lower Columbia River/I-5 corridor between Vancouver and Castle Rock. Admittedly a few of these locations have already experienced frost with low temperatures dropping down into the 33-35F range a couple times already this fall, but they have yet to officially hit 32F. /mh /Neuman .LONG TERM...Wednesday night through Sunday...Strong high pressure appears likely to continue across the Pacific Northwest into next weekend. More subtle details of whether or not the flow will be onshore or offshore Thursday and Friday remain somewhat uncertain so kept temperatures near to slightly above average during this time. Models do suggest upper level high pressure will begin to shift east of the region towards next weekend, which should open up the region to increasing southwesterly flow aloft and eventually allow cooler marine air to filter into the region. /Neuman && .AVIATION...VFR conditions under clear skies continue today. Winds have eased and will remain light/variable at most locations away from the Columbia River Gorge, with the exception of around KONP where breezy east winds also continue. Some of the sheltered valleys may see some shallow fog form, but the chance of this occurring at any terminal remains around 5 percent at best, so will continue to exclude any mention from the TAFs. KPDX AND APPROACHES...VFR through Monday. Surface winds light/variable overnight, but will again be east to 10-12 kt during the daylight hours on Monday. Cullen && .MARINE...High pressure maintains over the waters through much of this week. Surface thermal low pressure pushes inland, which will allow winds to ease over the waters. Small craft advisory will expire at 3 AM as planned. The offshore pattern weakens early this week with gusts dropping back down to the around 15 kt Monday and generally light winds across the waters for the remainder of the week. Sea conditions remain rather choppy with a pair of small swells and the residual offshore winds. The largest seas will be over the outer waters for the next day or two, but a larger westerly swell looks to arrive midweek. This swell will push seas back to 7 or 8 feet, before seas again subside to 5 ft late in the weekend. Cullen && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Freeze Warning until 9 AM PDT this morning for Central Willamette Valley-Lower Columbia-South Willamette Valley. WA...Freeze Warning until 9 AM PDT this morning for Greater Vancouver Area-I-5 Corridor in Cowlitz County. 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 CWA or forecast area.
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