Cape Shoalwater WA to Cascade Head OR out 10 NM Marine Forecast
|Today...E Wind 5 To 10 Kt With Gusts To 15 Kt Becoming Se 5 To 10 Kt By The Afternoon. Local Gusts To 20 Kt Near Gaps In Coastal Terrain. Wind Waves E 1 Ft At 4 Seconds Becoming Se. W Swell 4 Ft At 14 Seconds.|
|Tonight...S Wind To 5 Kt, Rising To 5 To 10 Kt Late. Wind Waves S 1 Ft At 4 Seconds. W Swell 5 Ft At 14 Seconds.|
|Sat...S Wind 5 To 10 Kt. Wind Waves S 1 Ft At 4 Seconds. W Swell 5 Ft At 12 Seconds.|
|Sat Night...S Wind 10 To 15 Kt, Rising To 15 To 20 Kt After Midnight. Wind Waves S 3 Ft At 5 Seconds. W Swell 6 Ft At 12 Seconds. Chance Of Rain.|
|Sun...Sw Wind 10 To 15 Kt With Gusts To 20 Kt. Wind Waves Sw 3 Ft At 5 Seconds. W Swell 7 Ft At 11 Seconds. Rain.|
|Sun Night...Nw Wind 10 To 15 Kt. Gusts To 20 Kt In The Evening. Wind Waves Nw 3 Ft At 4 Seconds. W Swell 8 Ft At 12 Seconds. Chance Of Rain.|
|Mon...Nw Wind 10 To 15 Kt. Wind Waves 3 Ft. Nw Swell 8 Ft.|
|Tue...Nw Wind 10 To 15 Kt, Becoming N 5 To 10 Kt. Wind Waves 2 Ft. Nw Swell 6 Ft.|
| Area Forecast Discussion|
National Weather Service Portland OR
936pm PST Thu Jan 27 2022
High pressure will remain over the area through the day on Friday but the weekend will bring a much awaited pattern shift. Expecting a round of precipitation beginning Sunday and persisting through Tuesday becoming showery in the middle of the week. Snow levels will drop with the incoming system on Sunday reaching around 1500 ft by Monday night.
.SHORT TERM...THROUGH SATURDAY NIGHT...Little change in the near short term forecast as the high pressure ridge remains anchored over the region. This vertically stacked area of high pressure is fairly robust and continues to keep skies clear and conditions dry. While the last several nigheights have brought widespread fog, tonight the environment seems a bit less likely to see the same outcome. Wind are slightly higher and the lowest levels of the atmosphere are much drier than in previous days which means that most likely will see frost instead of fog. The areas that may see a bit of a frost/fog mix would be the southern Willamette Valley where winds have been weaker through the day today. Speaking of winds, they have remained elevated throughout the western Columbia River Gorge and around the Portland-Metro area. Forecast pressure gradients are -8 mb between Troutdale and the Dalles through at least Friday morning, however models have been trending a bit too low with this gradient. Observed values are closer to -10 mb over the last few hours. Based on this trend, expecting this gusty winds to persist through Friday morning through the western Gorge, and easing overnight through the Portland area. With these winds in place, expecting wind chill temperatures in those areas to be in the low 20s, with higher values further south (due to almost no wind).
Interestingly today, there was a very clear boundary of where the higher winds were occurring within the Portland-Vancouver area. Values varied in a matter of 1 mile or so. Given the localized nature of these winds, decided to keep the Air Stagnation Advisory in place for all of Portland even though the winds were present. They did not cover enough of the area to justify eliminating the advisory. In addition, the inversion will likely build back in overnight bringing a return of the stagnant air conditions.
Little change into Friday and Saturday as the ridge begins to flatten and makes way for the incoming front on Sunday. Likely will begin to see clouds filling in on Saturday with more mild temperatures and lighter winds. -Muessle
SUNDAY THROUGH WEDNESDAY...A return to wetter weather is expected on Sunday as a front, stemming from the Gulf of Alaska, makes it's way southeast over the region. On Sunday afternoon will see winds transition to an onshore flow as the front makes landfall. Expecting some light precipitation on the leading edge, intensifying through the night into Monday. There is still quite a bit of disagreement in regards to the timing of the onset of precipitation on Sunday with ensemble models showing a variety of start times. However, in general it looks like the overall trend will be on Sunday evening.
As the front pushes inland, the winds will become a bit more northerly which will allow for colder air to filter into the area. This colder air will cause snow levels to drop to around 1500 ft by Monday night. While this seems like it could be the set up for widespread snow, that is not necessarily the case at this point. The big issue with the arrival of the cold air is the fact that the precipitation at that point will be showery and scattered in nature with limited accumulations. As it stands numerical ensemble models show around a less than 20% chance of low-land snow on Monday night into Tuesday, and nearly no chance south of Salem within the Willamette Valley. Now take all of that with a grain of salt as this snow potential will be greatly dependent on timing, placement, and precipitation rates. There is also a chance that the Valley, based on the wind direction becoming slightly more northwesterly, could be shadowed out of precipitation. At this point not hanging a hat on any amounts other than to say for low-lands, it looks minimal at best. The Cascades though will see accumulating snow and could see several inches between Sunday afternoon and Tuesday afternoon. Elevations above 5000 ft could see greater than 8 inches during that time frame.
Again, there is quite a bit of variability and uncertainty in the long term with confidence being fairly low. There are a lot of moving parts with this system and the picture is still fuzzy as to how they will all come together. Will continue to monitor but as it stands, not overly concerned for any significant snowfall. -Muessle
Weakening offshore flow should gradually result in winds turning from easterly to southerly tonight into Friday. Overall, expect rather benign conditions through Saturday considering it is January. A front appears likely to drop southeastward across the waters Sunday. This storm system will bring an increase winds and seas, but conditions appear likely to only top out in low end Small Craft Advisory level wind thresholds of around 20 to 25 kt Sunday. Seas may approach 10 ft behind this storm system towards Monday. An additional storm system will be possible towards the middle of next week, but many models suggest high pressure will return and bring another period of north to northeast winds to the waters. /Neuman.
NOAA Portland OR Office: Watches - Warnings - Advisories
OR...Air Stagnation Advisory until 4pm PST Friday 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.
WA...Air Stagnation Advisory until 4pm PST Friday for Central Columbia River Gorge-Greater Vancouver Area-I-5 Corridor in Cowlitz County-South Washington Cascade Foothills- Willapa Hills.