Marine Weather and Tide Forecast for Mount Shasta, CA

AVIATION
18/00Z TAFs...VFR should prevail at the terminals for the through early this evening with just some fair-weather clouds.
Gusty north to northeast winds will persist through the evening (peaking at 25-30kt), then ease after sunset. Local MVFR/IFR ceilings could impact the coast or portions of the Coquille/Umpqua basins late tonight or first thing Monday morning, but with offshore flow in place tonight, confidence is low in this occurring.
otherwise, VFR prevails through the TAF period. -Spilde/BR-y

PREV DISCUSSION
/Issued 305 PM PDT Sun May 17 2026/

DISCUSSION...

KEY MESSAGES...

* Gusty afternoon/evening winds will be at a peak of strength today, strongest east of the Cascades and in the Shasta Valley (with gusts of 25-40 mph).

* Freezing temperatures are expected east of the Cascades tonight.
Monday morning will be the coldest of the week. Brief, patchy frost is possible Monday morning, in Josephine and Jackson County valleys in Oregon. Highest chances (30%) are in the southern Illinois and Applegate valleys. There is a higher probability of frost in the Scott and Shasta valleys in Siskiyou County.

* Afternoon temperatures trend warmer Monday through Friday as high pressure builds in and remains over the area. Highs of 5 to 15 degrees above normal will be common. Morning lows on Tuesday will be chilly again on the east side. Otherwise, near normal across the area this week.

* Gusty afternoon and evening north to northwest breezes of near typical strength are likely each day.

* Night and morning low clouds are expected north of Cape Blanco each day, with a chance of patches extending into the Umpqua Valley on Wednesday morning.

* Northeast winds through Friday will keep the south coast clear or mostly clear, and bring above normal high temperatures of the upper 60s to mid 70s for Brookings.

The air mass is expected to be dry and stable this week. Forecast confidence is high through Friday. The cold, broad upper trough will continue tracking southeast from southeast Oregon across Nevada tonight, while high pressure nudges into our area from the west. Clear skies and winds diminishing after sunset will aid cooling tonight. The high will remain anchored offshore through Wednesday then build slightly eastward for additional warming on Thursday and Friday.

Slight cooling is possible next weekend, with a trough likely to move into western Canada. The majority of ensemble members keep the moisture associated with a couple of cold fronts well north of our area during next weekend. But, the second front, around day 8/Memorial Day could be strong enough and near enough for a marine push and chance of showers for Coos and Douglas counties northward.

MARINE
Updated 200 PM PDT Sunday, May 17, 2026
A thermal trough will bring a typical pattern of gusty north winds and steep to very steep seas over the coastal waters much of this week. Winds will be strongest and seas will be highest during the afternoons/evenings. Through this stretch, very steep seas of 10- 12 ft are most likely south of Cape Blanco with steep seas (6-9 ft)
north of Cape Blanco. Ensembles indicate winds will strengthen Wednesday into Thursday with a potential (50-70% chance) for gales across portions of the southern waters (especially from around Gold Beach south). -Spilde

MFR WATCHES/WARNINGS/ADVISORIES
OR
CA
None.

PACIFIC COASTAL WATERS...Hazardous Seas Warning until 11 PM PDT Tuesday for PZZ356-376.

Small Craft Advisory until 11 PM PDT Tuesday for PZZ350-370.