Marine Weather and Tide Forecast for Etna, CA

AVIATION
16/06Z TAFs...Two fronts will move through the region over the next 24 hours. One is pushing through now and the next is expected Wednesday morning into the afternoon. As each front passes through, expect a mix of MVFR/VFR cigs, including east of the Cascades, with local areas of reduced visibilities under any heavier precipitation. Overnight tonight, areas of IFR/LIFR are likely along the coast and into the Umpqua Basin once the current front passes through the region. These lower conditions will improve in advance of the next front on Wednesday. /BR-y

PREV DISCUSSION
/Issued 843 PM PDT Tue Oct 15 2024/

DISCUSSION...RADAR imagery is showing a band of precipitation associated with a frontal boundary moving across the coast at this moment with additional showers ahead of the front. This frontal band has produced some higher reflectivities offshore, and this may produce some higher rainfall than what is in the forecast. Have adjusted the forecast to reflect this better, however had to dust off my art and computer design skills as none of the models--including the high resolution models-- are handling this front particularly well. As a result, we may still be underdone on coastal rain; but time will tell. Please see the previous discussion below for more details. -Schaaf

MARINE
Updated 830 PM PDT Tuesday, October 15, 2024
Sub- advisory conditions under northwest swell dominated seas will persist through Wednesday. Multiple fronts will pass through the area between tonight and Thursday, brining rounds of precipitation and the potential for thunderstorms on Thursday north of Cape Blanco. Conditions could approach advisory criteria on Thursday as northwest swell briefly increases by a few feet, and seas steepen.
Seas lower again Thursday night into Friday, though moderate north winds will continue. High pressure builds in Friday into the weekend, bringing a break in the weather. /BR-y

PREV DISCUSSION... /Issued 250 PM PDT Tue Oct 15 2024/

SHORT TERM
This afternoon through Thursday night
An approaching upper trough has brought cooler temperatures and cloud cover across areas west of the Cascades this afternoon, with a few light showers observed in coastal areas this morning. This initial front will bring 30-60% chances for precipitation over inland areas as it continues eastward, with a slight increase to 60-80% chances over Modoc and eastern Lake counties early Wednesday morning. These eastern areas may get between 0.1 and 0.2 inches of precipitation.
Also on Wednesday morning, a weak disturbance trailing behind the initial front will bring another round of precipitation to the Oregon coast, Douglas County, and the Cascades. There are lesser 20- 50% chances for measurable rainfall (At least 0.01 inches) over other inland areas through the day Wednesday.

A second front will bring more widespread precipitation across the area on Thursday morning. Forecast rainfall amounts for Thursday are largely unimpactful, with coastal areas ranging from 0.15 inches at Brookings to 0.4 inches at Reedsport. Umpqua Valley areas are forecast to get 0.25 inches of rain, while other west side valleys will get 0.15 inches or less. Areas east of the Cascades could get between 0.01 and 0.1 inches of rainfall on Thursday. Precipitation chances start to decrease Thursday evening and are largely absent by Friday morning.

Cold air moving behind the front is expected to bring snow levels down to 4500-5000 feet on Thursday morning, making snowfall possible along the Cascades. Total snowfall at Crater Lake, Diamond Lake, and similar elevations is expected to be between 1 and 4 inches through Thursday morning and afternoon. NBM probabilistic guidance has a 25% for totals exceeding 4 inches, but most individual models stay in the lower ranges. Snow accumulation on roads is not expected, given residual surface warmth. However, slick roads and wet slush may be present on pass roads on Thursday. Extra caution is encouraged for anyone traveling over mountain passes, including Willamette Pass.

Gusty northerly winds will develop over areas east of the Cascades on Thursday afternoon. While advisory products are not expected, wind gusts of 25 to 35 mph across broad east side are noteworthy and worth acknowledging.

Finally, the cold air mass behind the second front will bring a significant drop in nighttime lows to most areas, especially east of the Cascades. Temperatures will be at or below freezing for east side areas on Wednesday and with additional cooling on Thursday.
Frost-bringing temperatures (33 to 36 degrees) are a possibility for west side valleys on Thursday night as well, excluding the Umpqua Valley. Additional guidance will help to determine of frost products are needed for these west side areas. -TAD

LONG TERM...Friday through Tuesday, Oct 18-22, 2024...Confidence in the weather pattern across the PacNW is high during the long term. Models are in agreement on an upper ridge building back into the area Friday with the ridge axis shifting overhead on Saturday.

This will be the first true taste of fall weather around these parts with cold nights/early mornings. In fact, this will probably be the first more widespread frost for the west side valleys from the Rogue- Umpqua Divide southward with areas of freezing conditions in portions of NorCal from Mt. Shasta westward Friday morning. Some uncertainty exists in the amount of cloud cover and/or fog that develops during the night, so this could have an impact on frost/freeze duration, but we'll have a better idea on this in the next couple of shifts. Another cold morning is expected Saturday.
Saturday morning could be just as cold since the air mass will have had an opportunity to dry out a bit. So, if you have sensitive plants/vegetation, both Thu/Fri nights are when you'll want to cover them up or move them inside. Other than some morning fog/low clouds, days will be sunny both Friday and Saturday with daytime high temperatures getting back to near and above seasonal normals. For Medford, this is upper 60s/low 70s and for Klamath Falls, Yreka and Alturas and Roseburg, this is the mid to upper 60s.

The ridge settles south and east of the Cascades Saturday night into Sunday allowing another front from the northeast Pacific to move into the area with increasing rain chances west of the Cascades, and especially coastal areas Sunday afternoon. The front moves through Sunday night into Monday morning with most precipitation fizzling before reaching our far SE zones (far southern Lake, Modoc and eastern Siskiyou counties) Monday afternoon. Still, there's another fairly high probability of rain (60-90%) from the Cascades west during this period.

Models have also come into better agreement regarding energy forming into a closed low offshore Tue/Wed of next week. While a very small number of ensemble members bring this trough onshore, the vast majority keep it far enough offshore to allow at least minor upper ridging to the east resulting in a dry period for the PacNW. We'll have to see how this evolves over the coming days, since closed lows are notoriously difficult to track (even during the near term).
-Spilde

MFR WATCHES/WARNINGS/ADVISORIES
OR...None.

CA...None.

PACIFIC COASTAL WATERS...None.