Marine Weather and Tide Forecast for Coos Bay, OR

AVIATION
20/00Z TAFs...VFR conditions will prevail into this evening, then a weak impulse will pass over the region tonight, with a marine push expected through the morning hours. This will result in IFR/MVFR ceilings over the marine waters and along the coast, and eventually the coastal valleys and Umpqua Basin, including at North Bend and Roseburg. Marine layer depth (up to around 5000 feet)
allows for the potential for some clouds to form and bank up against the Siskiyous Wednesday morning. These may cause local terrain obscuration but should be VFR above Medford. Elsewhere, VFR conditions will prevail through Wednesday morning. -Spilde

PREV DISCUSSION
/Issued 1259 PM PDT Tue May 19 2026/

KEY MESSAGES...

- Warm, dry weather prevails through late this week and into this weekend. Warmest days Thu-Sun with temperatures about 10-15F above normal.

- Afternoon/evening breezes should be fairly typical, though occasionally gusty along the coast.

- While the warm, dry conditions elevate fire weather risk, fuels are still in green-up/curing process and present generally low to moderate fire danger.

- Potential for a stronger trough early next week (Memorial Day)
bringing precipitation potential, gusty winds and a cool down.

DISCUSSION...High pressure and dry NW flow aloft will keep dry weather going through the remainder of this week along with a warming trend. Overall, high temperatures today and Wednesday will be a few to several degrees above normal, but warmer air aloft will bring temperatures around 10-15F above normal Thu-Sun.
The air mass is pretty dry, but we'll get marine pushes from time to time that will bring bouts of nighttime/morning stratus to the coast, coastal valleys and Umpqua Basin. One such marine push is coming tonight, which could be deep enough to cause some spillover clouds around the Rogue Valley Wednesday morning, but that's about it. By Friday pm/eve, models are showing a weak impulse offshore and some moisture/weak instability near the NorCal mountains (mainly south of here -- Sierra). This raises the idea of thunder, but the probability of anything occurring this far north is 10% or less. Same goes for Saturday pm/eve.

Looking ahead, there are indications that the ridge will begin to break down over the weekend, with the potential for a more robust trough to enter the Pacific Northwest around Memorial Day that could bring precipitation and cooler temperatures to the forecast area. Model suites still are not in solid agreement with this scenario, with several differences primarily in trough strength, but also its timing, so confidence is also still on the low side.
This will warrant a close eye for those with plans for the Memorial Day holiday. Most inland areas should have a 5-10F cool down along with enhanced to locally gusty winds, and a chance of showers. -Spilde

MARINE
Updated 200 PM PDT Tuesday, May 19, 2026
A thermal trough will bring gusty north winds and steep to very steep seas over the coastal waters through Friday night. 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. Guidance shows winds will strengthen Wednesday/Thursday with the potential (35-55% chance) for gales (gusts) across portions of the southern waters, especially from around Gold Beach south.

The pattern will ease some this weekend as an upper trough pushes in from the NW. This should bring lighter winds and lower seas, especially by Sunday. Model scenarios indicate another trough moving through Sunday night into Monday, but the strength of the trough is the main source of uncertainty at this time. We should get a better handle on this in the coming days. -Spilde

MFR WATCHES/WARNINGS/ADVISORIES
OR
CA
None.

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

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