Marine Weather and Tide Forecast for Long Beach, WA

SHORT TERM
Now through Sunday Night...So far this afternoon the bulk of the rainfall has been hung up over far NW Oregon and SW Washington just north of the Portland/Vancouver Metro as the an Atmospheric river coupled with a cold-frontal boundary begins its slow and final journey southward. Helping to drive this progression is a the arrival of a shortwave trough from over the eastern Pacific which is expected to arrive overnight.
High confidence among model guidance this'll further accelerate the front and rainfall through and then our of the region.
Exploring high resolution guidance like the HRRR shows moderate probabilities (40-50%) for a period of elevated rainfall rates greater than 0.25in/hr this evening into the overnight hours across the coast range and western slopes of the Cascades as the atmospheric river and strong cold front swing through the area.
While it's within the realm of possibility to see these higher rates over the valleys and I-5 corridor along the immediate frontal boundary, there are much better chances (50-80%) for rates closer to 0.10in/hr, especially around and east of I-5.
From 5pm this afternoon to 5am Saturday moderate to high confidence the Portland metro will see between 0.70-1.25 inches of rain, 0.60-1.10 inches in Salem, and 0.40-0.75 inches in Eugene. Obviously higher amounts are expected over the coast range (generally 1-2 inches) and Cascades (1-3 inches). This'll come into play when looking at the flooding treat, especially for urban, low-lying or other poor drainage areas and flashier small creeks/rivers as they remain highly sensitive to additional rainfall - see the Hydrology section for additional details regarding flooding concerns.

Headed through Saturday morning conditions rapidly improve as almost all deterministic and ensemble guidance show the last remnants of the atmospheric river exiting Lane County by 0700-1000. The remainder of the day appears mostly dry outside of some lingering shower activity primarily confined to terrain features like the Coast Range, Cascades, and adjacent foothills. Our attention turns to a ridge of high pressure attempting to establish itself over western CONUS Saturday night through Sunday into early next week. While this feature and a switch to broad southwesterly flow aloft is likely robust enough to raise our temperatures well above normal for early next week, it won't be strong enough to prevent the southern periphery of another atmospheric river headed into British Columbia from facilitating chances for light rain across far north Oregon and southwestern Washington starting Sunday afternoon into Sunday night. The overall pattern sees little progression from this point through the end of the long term period. -99

LONG TERM
Monday through Thursday...Looking into the start of next week, ensemble models show yet another Atmospheric River aimed at the Pacific Northwest and British Columbia however most ensembles maintain a northerly trajectory with a focus towards the Vancouver Island and northwest Washington.
That said, the latest guidance has shifted precipitation just a touch further south than what has been shown prior forecast cycles but it won't be enough to be impactful at this point. What dictates the placement of the axis of moisture next week will be the ridge amplitude to our south that is expected to slowly push eastward with time. IF the ridge weakens, then that would result in our area getting more precipitation than forecast. The ridge and southwesterly flow also push 850 mb temperatures to around 10 to 12 degrees C, which would lead to daytime highs into the 60s to near 70 for inland locations, 50-60s along the coast, Coast Range and Cascades through the middle of next week.
With temperatures this high snowmelt in the Cascades is probable. Looking at the latter part of Wednesday and towards the end of next week, another round of precipitation appears to be on deck. So, Spring 2026 looks to be in full swing for the Pacific NW. -99/42

AVIATION
A band of precipitation associated with an atmospheric river is moving southeast through SW WA and NW OR ahead of a surface front. The front and associated rain band will continue moving southeast overnight. Rain has already ended in a line from around KAST to KTDO and is expected to end for Portland area terminals around 09-12z Sat and KEUG by 12-14z Sat. Expect mainly MVFR conditions at all terminals while precipitation persists, with brief periods of IFR cigs/vis in heavier rain. The exception is KONP where LIFR/IFR conditions prevail. Conditions will then improve at each terminal to VFR around an hour or two after precipitation ends.
South to southwest winds continue around 10-15 kts with gusts up to 25 kts for inland terminals and up to 30 kts for coastal terminals.
Winds will weaken and shift northwesterly behind the frontal passage.

KPDX AND APPROACHES...Rain continues over the terminal, moderate at times, through 09-11z Sat. Southwesterly winds 10-15 kt with gusts up to 25 kt will weaken and become more northwesterly around 08-10Z Sat. -03

MARINE
Seas and southerly winds will remain elevated through late Saturday, therefore the Small Craft Advisory for all waters will be maintained until 11 PM Saturday. Winds will become northerly late tonight and through Saturday. Seas around 9 to 10 ft today will slowly ease below 9 feet by early Saturday. Beyond Saturday, conditions will remain rather benign until the start of next week. A quick moving system could result in seas briefly returning to 10 to 11 ft on Tuesday for all waters. At the moment, there is a 50-60% chance for seas to exceed 10 ft on Tuesday for the outer waters (beyond 10 NM) north of Cape Falcon OR and a 30-50% for the outer waters between Cape Falcon and Cape Foulweather OR. ~12

HYDROLOGY
Moderate rainfall associated with an atmospheric river across southwest Washington and far northwest Oregon is beginning to shift back south this afternoon and will continue to slowly move south tonight. Rain is expected to end for most locations by Saturday morning, except for some lingering precipitation across the central Oregon Cascades. With increasing rainfall rates, rivers are expected to rapidly rise, especially the flashier rivers that are already swollen near or at action stage. These include Johnson Creek near Sycamore, the Grays River near Rosburg, the Cowlitz River near Kelso, and the Wilson River near Tillamook, which are all currently in or forecast to go into Minor Flood stage. Another 6-8 rivers are forecasted to go into action stage.

As the next round of moderate rainfall moves through, minor flooding of urban, low-lying or other poor drainage areas remain possible Small creeks and streams remain highly sensitive to this additional rainfall. The Flood Watch remains in effect through Saturday afternoon, but may be able to be dropped as soon as the front pushes through early Saturday morning. Continue to monitor the latest river forecasts at water.noaa.gov as updates to forecast rainfall may dramatically affect forecast river levels. The majority of flood deaths occur in cars, and drivers should never attempt to cross a flooded roadway. Please heed any road closures posted by local authorities.

PQR WATCHES/WARNINGS/ADVISORIES
OR...None.
WA...None.
PZ...Small Craft Advisory from 2 AM to 11 PM PDT Saturday for PZZ210.

Small Craft Advisory until 11 PM PDT Saturday for PZZ251>253- 271>273.