Marine Weather and Tide Forecast for Idaville, OR

SHORT TERM
Now through Sunday night...Our latest upper-level shortwave trough and accompanying frontal boundary are pushing eastward tonight with lingering showers rapidly decreasing and tapering off. This is followed by increasing upper-level heights Saturday morning as the overall longwave pattern amplifies due in part to a strengthening low over the eastern Pacific - this’ll come in play late in the day. In the mean time, much of Saturday ends up fairly pleasant for early November, especially across the interior valleys. Thanks to the warm southerly flow aloft, daytime temperatures jump into the mid 60s along the I-5 corridor, around 7-11F degrees above normal for this time of year. Enjoy it while it lasts, because the conditions abruptly come to an end in the late afternoon and evening hours.

As alluded to, our attention shifts to another weather system that will push a stronger front eastward into the region late Saturday afternoon leading to stronger southerly winds and more widespread rainfall. For additional context, this front is on the far southern periphery of rapidly strengthening extra- tropical cyclone, and deterministic model guidance like the GFS, ECMWF, ECMWF AIFS, etc. have surface pressure values falling more than 24mb in 24hrs, so this front is technically the product of one these highly vaunted “bomb-cyclones”. Anyway, I digress. At least the confidence is high the core of this strong low pressure passes well north into British Columbia, but confidence is high we’ll still feel the impacts all the way down here in the Pacific Northwest.

As far as these impacts are concerned, the latest NBM guidance still has a 30-55% chance for wind gusts greater than 58 mph along the coast, and the REFS guidance has probabilities of 50-65% along coastal beaches and headlands. The overall set-up appears to support these probabilities as well, 925mb winds (~1800ft) right along the coast maxing out around 55-65 knots along the frontal boundary. Without a notable temperature inversion to keep these winds pinned above the surface, heavier precipitation and more convective elements along the the front will definitely have an opportunity to mix towards the surface.
Winds along the coast likely ramp up Saturday afternoon 1-4pm, peaking in the evening, then remain elevated through the overnight hours. The highest gusts along the coast likely fall between 4-11PM. A High Wind Watch remains in effect from 1 PM Saturday through 4 AM Sunday for the coast with the focus on exposed beaches, headlands, and other windy sites such as Clatsop Spit and Cape Disappointment.

Winds also increase across the interior lowlands Saturday evening and overnight, albeit not nearly as strong as the coast.
Both the latest NBM and REFS guidance indicate there is a 10-40% chance along the I-5 corridor for peak wind gusts above 40 mph Saturday evening, though the majority of wind gusts will likely be in the 20-35 mph range. A few downed tree limbs and isolated power outages are possible if gusts to exceed 40 mph, especially with trees with full compliment of leaves.

Rainfall totals with this late Saturday storm system do not appear concerning for river flooding given the quick moving nature of this disturbance. Confidence is high the region breaks to showers the second half of Saturday night into Sunday morning, followed by showers ending near sunset Sunday evening.
That said, there is a notable signal for an intense cold frontal rain band to materialize, but at this point, it still only appears there is a 10-25% chance for hourly rainfall totals exceeding a 0.25" per hour Saturday evening. This is typically the hourly rainfall amounts that are needed to produce nuisance urban flooding in October-December timeframe. With so many trees still leafed out, fallen leaves from this and our recent weather systems could clog storm drains and allow lower rain rates to produce isolated roadway flooding. Once showers end Sunday evening dry weather returns overnight with patchy fog across the inland valleys. -99/03


LONG TERM
Monday through Friday...Looking at next week, ensembles are in agreement that the progressive pattern will continue, but there is high uncertainty in the details on potential weather systems and therefore exact timing and magnitude of winds and rainfall. Euro and Canadian ensemble members are in general agreement that the next weather system will return rain sometime Monday into Tuesday, but the GEFS members are much more uncertain. There's another signal with all three ensemble systems in another weather system sometime late week or in the weekend. Fortunately, any signs of an overly impactful wind or rain event in the global ensembles is still relatively low (10-20% chance or less) at this point, though will need to keep an eye on flooding concerns depending on the strength of these weather systems as soils become more saturated from multiple rounds of rain. -03

AVIATION
Through 06Z Saturday...The frontal boundary has passed overhead with drier conditions quickly returning overnight.
Satellite observations show ample cloud breaks moving over the region and with the recent moisture confidence and lightening winds, the chance for fog formation have increased tonight, especially in the Willamette Valley. The REFS and NBM give KPDX, KUAO, KSLE, and KEUG around a 50-80% chance for IFR conditions by 10-18z with LIFR conditions possible as well (30-55%). Once southerly winds begin to slowly increase late Saturday morning into the afternoon hours, any IFR/LIFR conditions should scour out of the region with VFR conditions returning. Southerly winds increase further headed into the evening with gusts around 30-40+ knots along the coast by 00z onward. A band of rain shortly follows near the very end of the TAF period.

KPDX AND APPROACHES...Late this evening MVFR conditions are overhead, however, confidence is increasing for degraded conditions come 11-13z with a 60-80% chance for IFR conditions or lower 13-17z Saturday morning. Conditions likely improve back to VFR after this point although confidence is only low to moderate in the 17-19z timing currently in the TAF. Southerly winds increase ahead of an approaching frontal boundary Saturday late afternoon and evening. -99

MARINE
An active weather pattern will continue across the waters into next week. Southerly winds with gale force wind gusts up to 35 kt continue through this afternoon as the current front pushes through the waters. Afterwards, winds will quickly weaken below 15 kt behind the front this evening and overnight.
However, a persistent westerly swell will maintain steep and hazardous seas of 14 to 17 ft through Saturday morning.
Therefore, a Hazardous Seas Warning remains in effect through 10 AM Sat across all waters including the Columbia River Bar.

The next stronger front moves eastward across the waters late Saturday morning through late Saturday night. There is high confidence (>90% chance) for high-end gale force wind gusts of 40-45 kt across the waters Saturday evening. For the waters north of Cape Falcon there is a 50-70% chance at any given hour between 3-9 PM Sat for storm force wind gusts up to 50-55 kt. A result, a Storm Force Warning has been issued for all waters north of Cape Falcon including the Columbia River Bar from 10 AM Sat to 4 AM Sun. Behind this front, winds quickly die off and fall below 20 kt after 10 AM Sun.

A large westerly swell will also push into the waters on Sunday with high confidence for seas exceeding 20 ft. Latest guidance suggests seas peak between 20 to 25 ft between 1 AM to 7 PM Sun.
There is a 20-40% chance for seas exceeding 25 ft in the outer waters beyond 30 NM and north of Cape Foulweather. Seas gradually subside Sunday night into Monday. A series of weather systems will continue next week, impacting the waters and bringing additional rounds of small craft and gale conditions. -10

PQR WATCHES/WARNINGS/ADVISORIES
OR...High Wind Watch from Saturday afternoon through late Saturday night for ORZ101>103.
High Surf Advisory from 4 AM to 10 PM PST Sunday for ORZ101>103.
WA...High Wind Watch from Saturday afternoon through late Saturday night for WAZ201.
High Surf Advisory from 4 AM to 10 PM PST Sunday for WAZ201.
PZ...Hazardous Seas Warning until 10 AM PST Saturday for PZZ210- 251>253-271>273.
Storm Warning from 10 AM Saturday to 4 AM PST Sunday for PZZ210-251-271.
Gale Warning from 10 AM Saturday to 4 AM PST Sunday for PZZ252- 253-272-273.