090 FXUS66 KPQR 151803 AAA AFDPQR Area Forecast Discussion...UPDATED National Weather Service Portland OR 1002 AM PST Sun Nov 15 2020 Updated Aviation and Marine Sections .SYNOPSIS...Classic, unsettled November weather will prevail across the Pacific Northwest for much of the upcoming week. Expect seasonably cool temperatures and scattered showers today. The cold front which moved south of the forecast area late Saturday will lift back northward as a warm front, bringing another round of rain and mountain snow later tonight and Monday. Monday afternoon and evening will be mild and mainly dry, potentially with a few breaks in the clouds. Another strong front will push into the region for wet and breezy weather Tuesday, followed by another round of cool and unsettled weather through Thursday. Drier weather looks possible by next weekend. && .SHORT TERM...Today through Tuesday...As of 3 AM, the latest NOAA satellite and radar imagery shows our frontal zone sagging south of the forecast area, taking the steadiest precipitation with it. This front produced another decent round of rain and wind, with several inches of snow above the Cascade passes. Rainfall totals over the past 24 hours generally ranged from around 1 inch in the lowlands up to 3 inches for some of the wetter spots in the Oregon Coast Range and Cascades. The associated runoff continues to fill our rivers, most of which again saw modest rises from this system. Fortunately the heaviest rain remained south of the Willapa Hills, sparing the Grays River from any flooding. Snow showers continue in the high Cascades with mixed rain/wet snow at pass level. We allowed the Winter Weather Advisory to expire for the North Oregon Cascades, as we're only expecting a couple more inches of snow, and mostly above 4500-5000' elevation. Meanwhile, low-level cool air remains locked in the Hood River Valley, where there are likely some icy spots this morning. West winds should break through shortly, allowing temperatures to rise well above freezing today. Otherwise, today will be a fairly typical November "break" day between weather systems. Enough instability exists below 700 mb to support scattered showers, but there will probably be some shadowing to the lee of the Coastal Ranges and Cascades. Overall, today should be more dry than wet for most of the forecast area. Despite yesterday's front technically being a cold front, it should be a few degrees warmer today for most of the forecast area, with seasonable highs in the lower to mid 50s for the lowlands. A few patches of shallow morning fog will dissipate fairly quickly after sunrise. Models now showing the front lifting back north as a warm front Sunday night, with rain spreading northward overnight. Not expecting heavy rain with this system, but mostly 0.25 to 0.50 inch of rain for tonight through Monday morning. This warm front will lift north quickly Monday morning, with rain well north of the Columbia River by mid to late afternoon. Still decent amount of clouds across region. But, with no rain and some breaks in the cloud cover, seems reasonable to get afternoon temperatures into the upper 50s to lower 60s, especially for areas south of Salem. Dry weather on tap for Monday night. But, with high pressure east of the Cascades, and deepening low pressure well offshore, will see increasing easterly winds. Next system arriving Tuesday, with rain spreading inland early in the day. But, some uncertainty with this system. At moment, models trending with rather strong low offshore that will lift north- northeast towards Vancouver Island during the day. With that in mind, will likely stay on lighter precipitation side for most of the day, along with somewhat breezy east to southeasterly winds. But, if low tracks more eastward, then we could easily get into more rain and better potential for breezy south winds. For now, will go ahead with a High Wind Watch for this system Tuesday for the South Washington and North Oregon Coasts. Oregon's Central Coast may eventually need a watch if some of the more southern and eastern low tracks within the ensemble suite pan out. This system has the potential to produce very strong winds along the coast, or not, and much will depend on the track. Historically, models tend to be a bit too far south and east with rapidly intensifying lows off our coast, but not always. Either way, looks to be another wet day for the region. Another concern will be the potential for tidal overflow along the south Washington coast on Tuesday afternoon. Given uncertainty of wind speeds and seas, will have to watch this as draw closer. Weagle/Rocket .LONG TERM...No Changes. Previous discussion follows...Tuesday night through Friday...Cluster analysis shows a high probability that the region will continue to be on the leading edge of a deep upper level trough Tuesday night. The deep upper level low will shift north and dissipate by Wednesday night. The surface low will continue to strengthen Tuesday as it moves northeast towards Haida Gwaii. By Tuesday evening surface winds will likely shift onshore bringing stratiform rain within the warm front across the region. Gusty southerly winds are expected Tuesday night as gradients tighten within the warm front. NBM shows a 40% chance that KPDX will see wind gusts up to 35 kt, wind gusts will likely stay between 20 to 25 kt. These stronger gusts are possible if this low continues to strengthen like the models are depicting at this time. The 12Z GFS and NAM both show a weak shortwave ahead of the cold front which will likely support another rise in QPF Wednesday afternoon. Cold front will likely push onshore Wednesday night bringing showers across the area into Friday. Potential for a transitional period Friday as a transient upper level ridge moves across the Pacific NW. Weak surface ridging is likely to build Friday night which could bring a brief pause in the rain. But, as this is so far out confidence is low. /BPhillips && .AVIATION...Generally VFR over the area as of 18Z. Westerly orographic flow into the Coast Range and Cascades will maintain lower conditions at times through the day. The coast and interior lowlands will remain primarily VFR through at least 06Z Mon. However, as is typical in a post-frontal air mass, there will be brief periods of MVFR in showers. A warm front over southwest Oregon early this evening shift north tonight. Expect MVFR conditions to develop south of a KS12-KONP line after 06Z Mon, with IFR likely along the coast south of KONP. Conditions improve to VFR over the south part of the forecast area late Mon morning. MVFR conditions reach the northwest Oregon late tonight. For detailed regional Pac NW weather information, go online to: http://weather.gov/zse KPDX AND APPROACHES...VFR through the period. There will be brief periods of cigs around FL040 this afternoon through early evening, with a 20-30% chance of MVFR cigs associated with showers. Cigs 060-080 late evening into early Mon morning, then lowering after about 10Z as a warm front reaches the area. East wind 15g25kt to develop at the west end of the Gorge Mon morning. Weishaar && .MARINE...Wind speeds continue to subside this morning, generally 10-15 kt with gusts to 20 kt. Wind backs to southwest this afternoon and then southeast to south tonight. Models in decent agreement indicating a return to gale force wind over PZZ255 and PZZ275 mid to late Mon morning with a warm-frontal passage. East wind persists over the north zones into early Mon afternoon, followed by gale force south wind. Will maintain the current gale watch, but feel these conditions will be most prevalent over the outer waters. There is still plenty of model disparity regarding the strength and location of the surface low Tue. Specifically, the 06Z ECMWF ensembles show quite a bit of variability with surface low placement. In any event, latest models continue to suggest storm force wind Tue. Exact timing and magnitude remain in doubt due to the model variability. The ECMWF and ENP wave guidance show seas 20-22 ft over the northern waters this afternoon, with the highest waves along the south Washington coast. Buoy 46005 registered 30-ft wave heights at 02Z. This decays to around 22 ft at buoy 46029 early this afternoon. See no reason to adjust the forecast with no new information. Not having buoy 46089 makes it difficult to time the peak waves into the north Oregon coast. Seas ease into the mid- teens by 08Z Mon and to the low teens Mon morning. The ENP model shows 20-25 ft seas along the coastline Tue morning. The ECMWF model is 2-3 ft lower. Both models show this to be more of a southwest swell with relatively short periods. Expect somewhat more benign conditions during the second half of next week as higher pressure likely returns to the northeast Pacific. This looks like seas will drop below 10 ft for a multi- day stretch beginning Thursday. Weishaar && .PQR WATCHES/WARNINGS/ADVISORIES... OR...High Surf Advisory until 7 PM PST this evening for Central Oregon Coast-North Oregon Coast. High Wind Watch from Tuesday morning through Tuesday afternoon for North Oregon Coast. WA...High Surf Advisory until 7 PM PST this evening for South Washington Coast. High Wind Watch from Tuesday morning through Tuesday afternoon for South Washington Coast. PZ...Gale Watch from Monday morning through late Monday night for coastal waters from Cape Shoalwater WA to Florence OR out 60 NM. Storm Watch from late Monday night through Tuesday afternoon for coastal waters from Cape Shoalwater WA to Florence OR out 60 NM. Small Craft Advisory until 10 AM PST Monday for coastal waters from Cape Shoalwater WA to Florence OR out 60 NM. Small Craft Advisory until 10 PM PST Monday for Columbia River Bar. && $$ Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland