Marine Weather and Tide Forecast for Rainier, OR

DISCUSSION
Now through next Saturday...The short term forecast remains highlighted by onshore flow, seasonable temperatures, varying degrees of morning cloud cover and the continuation of dry weather.
Low to mid level clouds were stubborn to clear out Friday afternoon, with little to no clearing observed for most locations. The latest hi-res model guidance is not handling the extent of cloud cover well.
Nudged the sky cover forecast to the NBM 90th percentile to bump up coverage of clouds through Saturday morning. Expect at least some clearing Saturday afternoon, however cloud cover may struggle to clear again in some locations. If cloud cover lingers through most of the day, high temps will only top out in the 60s rather than the lower 70s.

Sunday is shaping up to be similar to Saturday, albeit several degrees warmer due to more sun breaks in the afternoon and a 2-4 degree Celsius increase in 850 mb temperatures. Expect widespread highs in the 70s, except 60s at the coast. With very little change to the weather pattern thereafter, conditions will be nearly the same on Monday with mostly cloudy skies in the morning becoming partly cloudy by the mid to late afternoon. Note a weak shortwave trough is set to move over northwest OR and southwest WA Monday morning, bringing mid to high clouds and virga or sprinkles, but most likely virga as model soundings show a layer of dry air from the surface up to 4000 ft.

Chances for rain actually making it to the ground increase late Tuesday through Wednesday morning as a weak Pacific cool front moves inland. With the airmass already primed with lingering mid-level moisture from the aforementioned shortwave trough, this front will likely be able to produce at least some measureable rain (under 0.1") across much of southwest WA, and a trace to 0.05" over the Portland/Vancouver metro. Locations from Salem to Eugene only have a 10-20% chance of rain with this front, with conditions most likely staying dry. Even if rain does occur in the central/southern Willamette Valley, only expect a trace to 0.01".

Beyond this system, persistent onshore flow will maintain near normal temperatures on Thursday with below normal temperatures Friday through next Saturday. Models and their ensembles remain in good agreement a cool upper level low will move directly over Washington and Oregon Friday into Saturday, bringing widespread chances for showers both days. The vast majority of ensemble guidance shows at least some measurable rain across all of northwest OR and southwest WA with this system (only ~5-10% of the total ensemble space from the ENS/GEFS/GEPS is showing no rain at all). With the cool air aloft, fairly steep mid-level lapse rates and abudant mid-level moisture, the grand ensemble mean is showing around 200 J/kg SBCAPE during peak heating hours on both days. If enough sunbreaks occur and surface heating is sufficient, some showers will have the potential to produce locally heavy rain. Note NBM thunder probabilities are currently under 10%, but nonzero. For rain amounts, there is a 20- 40% for 0.25" or more, except 45-55% along the coast, western slopes of the Coast Range, Willapa Hills and Cascades/foothills. If rain amounts this high do occur, it would be the most rain the area has seen thus far this month. -TK

AVIATION
A broad upper level trough remains over the region, continuing north to northwesterly winds at the surface through the TAF period. Inland winds will remain around 5-10 kt through the period, highest during the afternoon. Along the coast between 18Z Saturday and 06Z Sunday, winds will range between 10-15 kt with gusts up to 25 kt, then decrease to 5-10 kt thereafter.

Conditions will stay VFR through most of today, with CIGs remaining around FL035 to FL050. By 06-08Z Sunday, MVFR conditions will likely return to the coast (mostly KTMK and northward). There is a 30-50% chance of MVFR conditions for KAST, while only a 10-20% chance at KONP.

*KTTD ASOS is currently INOP except for altimeter and will be AMD NOT SKED.

PDX AND APPROACHES...Expect VFR conditions to persist through the TAF period. Low end VFR CIGs around FL045 this morning will clear out by this afternoon, around 21Z Saturday. North to northwesterly winds 5-10 kt, highest in the afternoon.
~Hall

MARINE
North/northwesterly flow continues, with diurnally driven peaks in the afternoon. Winds 15-20 kt expected with gusts to around 25 kt south of Cape Falcon to Florence this afternoon and evening. A short, low end Small Craft has been issued and is in effect from 2 pm to 11 pm today. Seas are generally wind driven at 3 to 5 ft. This pattern is expected to persist through the weekend.

A weak disturbance is expected to cross the region on Monday, supporting southerly winds. A westerly swell is also expected to move into the waters late Monday, generally around 5 ft at 10 seconds. Combined seas still remain 7 ft or less. -Batz

PQR WATCHES/WARNINGS/ADVISORIES

OR...None.
WA...None.
PZ...Small Craft Advisory from 2 PM this afternoon to 11 PM PDT this evening for PZZ252-253-272-273.