Marine Weather and Tide Forecast for Mount Shasta, CA

AVIATION
20/06Z TAFs...A stable air mass looks to keep a familiar pattern in the forecast. Valley fog with LIFR will become widespread in the valleys in Douglas and Josephine County then gradually improve to VFR Tuesday afternoon. However, expect fog or low clouds with LIFR to linger in Roseburg and Grants Pass. Fog is expected to briefly develop in Medford again early Tuesday morning. Confidence is low for got North Bend given the offshore easterly winds, so will monitor this and update the TAF as necessary.

Other areas are expected to stay at VFR levels through the TAF period.



PREV DISCUSSION
/Issued 222 PM PST Mon Jan 19 2026/

DISCUSSION...A stable air mass remains over northern California and southern Oregon. This will keep daytime highs above seasonal norms, cool nights, and uneventful weather in the forecast through much of the week. With poor atmospheric mixing continuing into midweek, a Stagnant Air Advisory remains in place through Wednesday afternoon.
Fog is lingering in the Umpqua Valley and at Grants Pass this afternoon, and redevelopment is expected in these areas as well as into the Illinois Valley this evening into Tuesday. A Dense Fog Advisory for the Umpqua Valley and a Freezing Fog Advisory for the Illinois Valley and Grants Pass are in place. A thin layer of patchy fog did reach Central Point/north Medford and North Bend this morning, but coverage was brief. This pattern may also repeat on Tuesday morning.

On Tuesday, an upper trough presses against the ridge before splitting and sending a cutoff low to the southwestern United States. This will weaken then flatten the ridge, bringing a period of northwest flow. This pattern change will help to cool daytime highs across the area to nearly seasonal levels, and some upper level disturbances may help to mix out stagnant air. Other effects look unlikely. At the very most, there's a slight chance (10-20%)
for light coastal showers on Friday.

While a general pattern is noticeable in guidance for the weekend and beyond, uncertainty reigns in the details. An upper ridge looks to return towards the end of the weekend, but forecast 500mb heights are lower than current ones, indicating weaker high pressure and cooler temperatures. Long-term deterministic guidance shows variations in where the ridge axis is, as well as fronts either flattening or pushing the new ridge to the east in the following days. With those variations as well as unclear signals in ensemble meteograms, there's little confidence to offer for when precipitation will return. -TAD

MARINE
Updated 200 PM PST Monday, January 19, 2026
Below advisory seas remain in the forecast for area waters. Northerly winds increase slightly over outer waters into Tuesday morning, but are not expected to build steep seas. Winds turn southerly on Tuesday then back to the north on Wednesday, with gusts increasing into Thursday. This period of gusty winds may build steep seas for waters south of Coos Bay on Thursday morning, with areas of steep seas looking to last into Saturday morning as winds ease. -TAD

BEACH HAZARDS
Updated 300 AM PST Monday, January 19, 2026
A low amplitude (3-6 ft), but long period (18-20 seconds) swell is expected to move into the coastal waters tonight and persist through Tuesday afternoon. This will increase the risk of sneaker waves on area beaches, especially on the incoming tide Tuesday morning.

If you plan to visit area beaches, please be aware of the dangers sneaker waves pose to beach goers. Sneaker waves can run up significantly farther on beaches than normal, including over rocks and jetties. These waves can suddenly knock people off of their feet and sweep them into the ocean. The waves can also move logs or other objects which could crush or trap anyone caught underneath. While sneaker waves can occur at any time, the greatest risk is on an incoming tide. Please be aware of the tides if venturing out onto the beaches. NEVER turn your back on the ocean!

MFR WATCHES/WARNINGS/ADVISORIES
OR...Beach Hazards Statement through Tuesday afternoon for ORZ021- 022.

Air Stagnation Advisory until 4 PM PST Wednesday for ORZ023-024- 026-029>031.

Dense Fog Advisory until noon PST Tuesday for ORZ023.

Freezing Fog Advisory until noon PST Tuesday for ORZ024.

CA...None.

PACIFIC COASTAL WATERS...None.