Marine Weather and Tide Forecast for Clatskanie, OR

SHORT TERM
Now through Sunday night...The persistent weather pattern the area has been stuck under over the past week will finally come to an end today as a Pacific frontal system moves inland, bringing widespread rain and Cascade snow. Low-level flow will eventually turn back onshore today, bringing an end to easterly winds in the Columbia River Gorge. Stagnant air concerns for inland valleys away from the Gorge will also come to an end due to increased mixing and precipitation. The increased mixing has already helped fog lift over the southern Willamette Valley with observed surface visibilities now up to 5-9 miles as of 2:45am Saturday. With the improving visibilities, have decided to cancel the Dense Fog Advisory. With the increasing low level mixing and precipitation, have also cancelled the Air Stagnation Advisory that was in effect for inland valleys away from the Gorge. In response, expect air quality to gradually improve today.

How much precipitation will this weekend weather system bring? Confidence is very high for rain amounts over 0.5 inches from 4am Sat-4am Sun as NBM probabilities are now around 95%, except 80% in Eugene-Springfield, Cottage Grove, Creswell and Oakridge.
Probabilities for rain amounts over 1" have increased slightly to 10-20% in the Willamette Valley and Portland/Vancouver metro.
Meanwhile, the coast, Cowlitz Valley and lower Columbia have a 50-75% chance. In the Cascades, precipitation will eventually fall as snow down to around 3000 feet. Snow levels start off high Saturday morning at over 9000 ft before lowering to around 5000 ft Saturday afternoon and then down to 3000 ft Saturday night. Snow levels should remain nearly steady thereafter, at least through Sunday night. Confidence is high for a solid 6-10 inches of snow in the south WA/north OR Cascades above 3000 feet (80% chance for 6 inches or more). The period of heaviest snowfall is expected to occur late Saturday night through Sunday morning. With travel impacts expected at pass level, have decided to issue a Winter Weather Advisory for the south WA/north OR Cascades above 3000 feet. Minimal impacts and snow amounts are expected for Santiam Pass and Willamette Pass where only 1-3 inches of snow is likely to fall.

High pressure starts building into the area again Sunday night, bringing an end to any lingering post-frontal showers and a return to calm winds. With high pressure in place and recent rainfall, expect areas of dense fog to develop over inland valleys Sunday night. -TK


LONG TERM
Monday through Friday night...Models and their ensemble continue to suggest ridging over the northeast Pacific will begin building into western WA/OR Monday into Tuesday, bringing a return to dry weather. With a 1030-1032mb surface high in place during that time, winds will be light aside from the redevelopment of breezy east winds in the western Gorge. Chances for max wind gusts over 40 mph are around 20% in Troutdale and 50% in Corbett. Overall the strength of east winds early next week looks to be noticeably weaker than what has been observed over the past several days. Skies will likely clear out as well, aside from the Willamette Valley and Upper Hood River Valley where areas of dense fog and low clouds will develop overnight and likely persist through the day. No air stagnation concerns with this high pressure system as these conditions will be fairly short-lived. Chances for precip return late Wednesday and increase to 75-85% Wednesday night. Chances for rain then remain in that range through Friday night. These probabilities are up a bit from last night. Still no concerns in particular with the two frontal systems late in the week. Overall the weather pattern looks fairly typical for this time of year. -TK

AVIATION
Currently as of 11Z Saturday, low-end MVFR/IFR conditions along the coast with some light rain, and mostly VFR with a few terminals experiencing MVFR conditions. Easterly winds in the Columbia River Gorge continue to bring gusts up to 25-30 kt at KTTD.

An approaching front over the coastal waters continues to move eastward over the coast, bringing rain and continued MVFR conditions to coastal terminals. The front will move inland by 14-15Z Saturday, bringing similar conditions to inland terminals.
There is a 30-50% chance that conditions could occasionally lower to IFR for all terminals between 15-20Z Saturday. In addition to the frontal passage, there will be a brief period of possible LLWS at KPDX, KTTD and KUAO between 12Z to 18Z Saturday. All terminals are expected to improve back to low-end VFR by 00Z Sunday as the front passes and CIGs lift. Winds will be mostly southwesterly and just under 10 kt, with gusty winds at KTTD expected to weaken to under 10 kt by 18Z Saturday.

PDX AND APPROACHES...Currently low-end VFR conditions with breezy east winds as a result of gusty winds within the Columbia River Gorge. MVFR conditions are expected to develop around 14-15Z Saturday as an oncoming front begins pushing in. LLWS could manifest for KPDX around 12-18Z Saturday, which will coincide with the frontal passage. Conditions should improve back to VFR by 00Z Sunday. ~Hall

MARINE
A front this morning will continue to bring Small Craft Advisory conditions to the north and central waters, then all waters by 7 AM. Expect wind gusts up to 30 kt and seas around 9 to 12 feet through early today. Seas will continue to build towards 16 to 19 ft (70%-80% probability) by late tonight/early Sunday. Seas will then settle into the 11 to 14 ft range by late Sunday/early Monday and likely fall below 10 ft by Monday afternoon. Next disturbance will arrive late Tuesday, likely to bring more Small Craft Advisory conditions. ~Hall

PQR WATCHES/WARNINGS/ADVISORIES

OR...Winter Weather Advisory from 4 PM this afternoon to 4 PM PST Sunday for ORZ126.

WA...Winter Weather Advisory from 4 PM this afternoon to 4 PM PST Sunday for WAZ211.

PZ...Hazardous Seas Warning from 1 AM to 4 PM PST Sunday for PZZ210- 251>253-271>273.

Small Craft Advisory until 1 AM PST Sunday for PZZ251-252-271- 272.

Small Craft Advisory from 7 AM this morning to 1 AM PST Sunday for PZZ253-273.