Cascade Head to Florence OR from 10 to 60 NM Marine Forecast
| Rest Of Today...S Wind To 5 Kt. Wind Waves S 1 Ft At 4 Seconds. Nw Swell 3 Ft At 9 Seconds. Widespread Dense Fog In The Morning. Areas Of Dense Fog In The Afternoon. |
| Tonight...N Wind To 5 Kt. Wind Waves N 1 Ft At 4 Seconds. Nw Swell 3 Ft At 9 Seconds. Areas Of Dense Fog In The Evening. Patchy Dense Fog After Midnight. |
| Wed...Ne Wind 5 Kt, Backing To Nw To 5 Kt In The Afternoon. Wind Waves Ne 1 Ft At 4 Seconds, Shifting To The Nw At 4 Seconds In The Afternoon. Nw Swell 3 Ft At 9 Seconds. Patchy Dense Fog In The Morning. |
| Wed Night...Nw Wind 5 Kt, Backing To Se After Midnight. Wind Waves Nw 1 Ft At 4 Seconds, Shifting To The Se At 4 Seconds After Midnight. Nw Swell 3 Ft At 9 Seconds. |
| Thu...S Wind 5 Kt. Wind Waves S 1 Ft At 4 Seconds. Nw Swell 3 Ft At 10 Seconds. |
| Thu Night...N Wind 5 To 10 Kt. Wind Waves N 2 Ft At 4 Seconds. Nw Swell 3 Ft At 10 Seconds. |
| Fri...N Wind 5 To 10 Kt. Wind Waves 2 Ft. Nw Swell 4 Ft. |
| Sat...Nw Wind 5 To 10 Kt. Wind Waves 2 Ft. Nw Swell 4 Ft. |
| Area Forecast Discussion ...UPDATED National Weather Service Portland OR 1006am PST Monday Dec 15 2025 ...Updated aviation discussion... Synopsis A series of complex frontal systems will move through the area this week each bringing chances for strong winds, heavy rain, and river flooding later in the week. Each system has the potential to be impactful in it's own way. In the short term, the main concerns lie with rain on Monday, and wind on Tuesday. There are increasing probabilities of some interior areas meeting Wind Advisory criteria on Tuesday. Heavy rain returns on Thursday but is shifting further south to areas that did not receive as much rain the last time around. .SHORT TERM...Now through Wednesday...The next 48 hours will be quite dynamic with widespread rain and gusty conditions. Current radar and satellite shows widespread rain over the region with totals ranging from 0.1-0.4 inch of rain since midnight with the northern portions of the forecast area seeing more rain than south of Newberg. Rain will continue today with heavier accumulations along the coast this morning and shifting eastward through the day. The bulk of the front will have passed by sunset. The threat today continues to be wind as strong southwesterly flow takes over. Aloft a very strong jet stream at 35,000 ft is passing over. This jet is coupled with a low level jet at right around 5000 ft. This jet has the potential to mix strong winds down to the surface. At 3500 ft and above winds are currently around 40-50 mph but that will amplify through the morning and early afternoon. There is one factor about this front that may assist in keeping the interior valleys less windy. This is a warm frontal passage and therefore an inversion is in place as it moves over. This inversion can act like a barrier keeping the wind from mixing down. However, as it breaks down in the afternoon there is the potential for gusts up to 40 mph inland. There is around a 10-15% chance for gusts up to 40 mph within the Willamette Valley and around a 50-60% chance of gusts up to 40 mph along the Cascade Foothills. The NBM 24-hr maximum gusts is showing around a 60-70% chance of gusts greater than 45 mph this afternoon, however that is likely an instantaneous gust. Even with those probabilities have decided against issuing a Wind Advisory for the northern Oregon Cascade Foothills given the lack of confidence in the prolonged period of time. With all that being said though, the rain from the past several days have made soils incredibly saturated and therefore cannot rule out tree damage from even instantaneous gusts. As higher resolution models arrive we will continue to monitor. Overnight conditions will ease slightly allowing for a brief period of recovery. It will be short-lived though as yet another frontal system approaches. Looking at the ensemble low locations, there is high confidence in a concentrated low center moving up and over Vancouver Island. This low will drive the weather on Tuesday which has shifted a bit since previous forecasts. Again, this frontal system appears to move fairly quickly across the area Tuesday night, with the heaviest precipitation expected between 4pm Tuesday - 10am Wed. Total rainfall amounts are likely to be similar to or slightly higher than today's system. The change comes in regards to wind. Concern continues to rise regarding the potential for another round of strong wind on Tuesday. A component to watch for in these scenarios is the low level jet. Typically at around 975-850 mb, the stronger these winds the higher probability of mixing down to the surface. The flow aloft is westerly while surface flow is southwesterly. At 850 mb (around 5,000-7,000 ft) wind speeds between 7PM Tuesday and 4am Wednesday range from 55-70 mph. Again, there is an inversion in place that could inhibit their ability to reach the surface. Increasing confidence in Gusts greater than 45 mph along the Coast Range and even inland. There peak wind gusts shows up to a 20-30% chance of wind gusts up to 58 mph around the highest points of the Coast Range and along the coast on Tuesday. Easily will see gusts exceeding 60 mph along the Cascades and above 3000 ft. Given the variable nature in this system and the pace/strength of the low, will wait for the next round of higher resolution models to give a bit more details to determine if any hazards are needed. Wednesday is almost a recovery day from the two bouts of rain and wind. Now that's not to say that we won't see active weather, but the overall impact appears to be lower. Snow levels are expected to drop significantly by Wednesday morning with the passage of the upper trough. This will allow for snow to begin accumulating at pass level on Wednesday. The weather setup on Wednesday will feature onshore flow with zonal flow aloft, likely maintaining showers enhanced by orographic effects. There still remains some uncertainty regarding snowfall amounts through Wednesday night, as probability for more widespread mountain snow of 12 inches or more have come down except on the volcanos. There is still a period of time on Wednesday into Thursday where 6+ inches of snow may fall around the passes. Ultimately it will come down to when the cold air and precipitation mesh. -27 As the synoptic pattern progresses into late next week there is a trend for yet another atmospheric river on Thursday into Friday. At this point, confidence remains low as there remains significant differences between ensembles, but these have gradually been coming into better agreement over the past 48-hours. The WPC (Weather Prediction Center) has maintained a slight risk of excessive rainfall across most of western Oregon, which means there is increasing probability of exceeding flash flooding guidance. With our soils very saturated and rivers full, adding the Thursday- Friday system, local area rivers could see potential flooding. There remains quite a bit of variability as to where the plume of moisture and highest IVT values set up, but indications are that these 24 to 48-hr rainfall amounts Thursday into early Friday are likely to be the highest of the week. Latest model runs have shifted the system farther north with more west-southwest flow. This would also push snow levels higher in the Cascades through Thursday night. With the potential for heavier rainfall late in the week, probabilities for local tributary rivers reaching at least minor flood stage have increased to around 30-50%. Moderate flood stage remains low around 10-20%. Again, still quite a bit of uncertainty. But moving into the weekend, conditions likely ease with clusters showing low amplitude troughing likely over the Pacific NW. Showers will likely continue with lower snow levels. There is around a 10% chance that snow flakes or a snow/rain mix falls to around 1500 ft in the foothills. /DH Long Term Thursday through Sunday...Now as we transition into the later half of the week the weather appears to ramp back up with a trend towards another atmospheric river. On Thursday we will experience the highest precipitation of the long term forecast as it bleeds into Friday. The challenge with this specific system is that there is a lack of consistency with the synoptic flow. The atmospheric river has a high probability of occurring, but models are showing several shortwaves and lows trailing behind it in the flow. This would lead towards a more prolonged system vs a short burst of rain like the Monday/Tuesday systems. However, if you look at the guidance we typically use for atmospheric rivers, they show similar features to that of the earlier events. At this point, confidence is incredibly low but if we maintain the cold air with lowered snow levels, we could be looking at our first heavy snowfall of the season. In fact, the mean of the NBM 48-hr snowfall amounts shows as much as 35 inches of snow for Thursday & Friday combined at Mt Hood. There is a 10% chance of nearly 4 feet in those 48 hours. However, if the snow levels rise like they may do if the atmospheric river shifts further north, then we would see significantly less snow with a 10% chance of only 15 inches of snow. If you're planning on traveling over the passes this weekend, please continue to track the forecast shifts as this system develops further. With the influx of additional heavy precipitation flooding again rises as a concern. While the extent of the flooding is not forecast to be as widespread at this point, we must still be diligent as there are still a number of rivers that are forecast to reach flood stage. Therefore, if you live near any rivers, please visit www.water.noaa.gov/wfo/pqr for localized forecasts. Precipitation remains through the weekend. -27 Marine A strong cold-frontal system is slated to pass through the waters today (Monday) leading to fairly impactful conditions across the waters. Gale Warnings are in effect for the inner and outer waters, including the Columbia River Bar, through the daytime hours with high confidence in sustained winds of 25-35 kt with gusts of 40-50 kt. At this point isolated storm-force gusts associated with a coastal jet accompanying the frontal boundary can't be ruled out Monday morning with a 35-45% chance of occurring somewhere along the southwest Washington or northwest Oregon coasts, and only 10-20% chances across the outer waters. While winds peak Monday morning, seas continue to build into Monday afternoon before slowly easing on Tuesday. Seas will most likely reach into the 15-18 ft range Monday afternoon, with a 10-35% chance of surpassing 18 ft beyond 30 NM north of Cape Falcon - 10% or less elsewhere. By Tuesday afternoon, significant wave heigheights are likely closer to 11-14 ft with a dominate period of 11-12 seconds. Going forward a rather active weather pattern, even by December standards, continues through the work week bringing additional winds and wave hazards to the coastal waters. Seas are very likely to remain elevated above 10 ft (greater than 90% confidence) from Wednesday through Friday as additional weather systems move onshore. At least models are beginning to hint as some larger breaks between weather disturbances next weekend into the following week, but at this 7-8 day time-scale, the confidence in this slowdown materializing is only low to moderate at this time. -99/36 NOAA Portland OR Office: Watches - Warnings - Advisories OR...High Wind Warning until 1pm PST this afternoon for ORZ101-102. Wind Advisory until 4pm PST this afternoon for ORZ106-107. WA...High Wind Warning until 1pm PST this afternoon for WAZ201. Wind Advisory until 4pm PST this afternoon for WAZ203. PZ...Gale Warning until 4pm PST this afternoon for PZZ210-251>253- 271>273. Hazardous Seas Warning from 4pm this afternoon to 4am PST Tuesday for PZZ210-251>253-271>273. Small Craft Advisory from 4am to 4pm PST Tuesday for PZZ210- 251>253-271>273. |
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