Cape Shoalwater WA to Cascade Head OR out 10 NM Marine Forecast
| Rest Of Today...Sw Wind 5 Kt. Wind Waves Sw 1 Ft At 4 Seconds. Nw Swell 2 Ft At 9 Seconds. Widespread Dense Fog In The Morning. Areas Of Dense Fog In The Afternoon. |
| Tonight...Nw Wind To 5 Kt. Wind Waves Nw 1 Ft At 4 Seconds. Nw Swell 2 Ft At 9 Seconds. Areas Of Dense Fog In The Evening. Patchy Dense Fog After Midnight. |
| Wed...N Wind 5 To 10 Kt. Wind Waves N 1 Ft At 4 Seconds. Nw Swell 2 Ft At 9 Seconds. |
| Wed Night...N Wind 5 To 10 Kt. Wind Waves N 2 Ft At 4 Seconds. Nw Swell 3 Ft At 9 Seconds. |
| Thu...Ne Wind To 5 Kt, Backing To Nw 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 10 Seconds. |
| Thu Night...Nw Wind 5 Kt. Wind Waves N 1 Ft At 4 Seconds. Nw Swell 3 Ft At 10 Seconds. |
| Fri...Nw 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 National Weather Service Portland OR 254pm PDT Tuesday Mar 17 2026 Synopsis Through the remainder of the work week the region remains on the northern periphery of an upper-level ridge of high pressure facilitating much warmer than normal conditions. However, an atmospheric river aimed at northern Washington and Vancouver Island will occasionally wobble southward from time to time giving portions of the region chances for rain, especially in Pacific/Wahkiakum County and along the north Oregon coast. Then over the weekend we'll trend cooler as a trough swings into the Pacific Northwest although forecast confidence degrades from this point onward due to increasing model uncertainty. .SHORT TERM...Now through Friday...This afternoon current radar and satellite data shows light rainfall attempting to push inland but surface observations show little accumulation so far away from the coastline. Thanks to a very dry airmass aloft highlighted on the morning KSLE sounding, it's likely most of the precipitation around the I-5 corridor is falling as virga as it gets eaten away/evaporated by the much drier airmass above the surface. In sharp contrast, portions of far western Pacific county have clocked upward of 2 inches of rainfall over the last 12 hrs. Moving through the next several days the large scale pattern of an upper-level ridge to our south-southeast and troughing over the north half of British Columbia will hold in place with fairly similar conditions day to day. While the upper-level ridge almost certainly facilitates "warm" conditions over the area, our focus remains on the an Atmospheric River (AR) taking aim at the western Olympic Peninsula and Vancouver Island. The push and pull of both the aforementioned trough and ridge feature will help to modulate the placement of the AR. Overall, rain will be most persistent over Pacific County and the far north Oregon coast; these areas have additional rain totals ranging between 0.60-3.50 inches between 5pm today through 5PM Friday - highest totals north Pacific County. Otherwise conditions remain dry most hours inland through Friday, particularly south of the Portland/Vancouver Metro area. Given the broad southwesterly flow aloft and 850mb temperatures above the surface at 10-13C (anomalously warm for this time of year) Portland southward, high temperatures respond in-kind likely rising into the the mid to upper 60s across the lowlands. Can't rule out lower to mid 70s around Lane County as well. The primary piece of uncertainly in regards to temperatures will be the amount of mid to high cloud cover from the system to our north, if skies are clearer than forecast particularly Thursday afternoon, the north Willamette Valley and Portland metro have a better shot at meeting/exceeding 70 degrees - a 30-40% chance according to the latest NBM. It's also worth quickly noting the dry airmass aloft will be sticking with us aloft leading to poor daytime and nighttime relative humidity values for the higher peaks in the Cascade foothills and central Oregon coast range. -99 Long Term Friday night through Tuesday...This weekend the large scale pattern finally shows signs of progressing although it remains to be seen how exactly this will play out in the forecast as deterministic and ensemble model uncertainty begins to grow. The current consensus is for an upper-level shortwave and accompanying cold front to kick westward into the Pacific Northwest Friday night and/or Saturday leading to increasing precipitation chances across the inland valleys. However, models do show a spread in the potential amplitude and strength with this system and given the dry airmass in place near the Cascades would tend hedge towards the lower-end rainfall solution. Uncertainty grows further early next week as ensembles struggle resolving the large scale pattern aloft. By late Monday into Tuesday, around 50% of the ensemble space shows a trough sitting just of the coastline with closer to normal temperatures remaining in place and better rainfall chances. Another 30% of ensembles have the ridge to our east a bit more overhead which would keeps the inland areas drier and warmer, and then the remaining 20% put the ridge of high pressure directly overhead leading to much drier and warmer conditions than currently forecast. In any case the majority of ensemble members hint at another trough arriving around the middle of next week. -99 Marine Southerly winds across all waters expected through the middle of the week. Increased wind gusts will be possible through the evening as a cold front sags southward toward the northern Oregon and southern Washington coasts. Wind gusts up to 25 kt will be possible for zones north of Cape Foulweather, including the Columbia River Bar through early tonight. Seas of 8 and 11 feet at 10 to 13 seconds as winds increase and a southwesterly to westerly swell moves into the waters. Conditions subside below Small Craft conditions on Wednesday. Chances for Small Craft conditions remain low for the weak system that moves through on Thursday. -19/42 NOAA Portland OR Office: Watches - Warnings - Advisories OR...None. WA...None. PZ...Small Craft Advisory until 5am PDT Wednesday for PZZ210-251-252- 271-272. |
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