San Juan Islands and Northern Inland Waters Marine Forecast
| Tonight...Sw Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. A Slight Chance Of Rain After Midnight. |
| Sun...S Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. |
| Sun Night...S Wind 5 To 10 Kt, Easing To Around 5 Kt After Midnight. Waves Around 2 Ft Or Less. |
| Mon...Se Wind Around 5 Kt, Rising To 5 To 10 Kt In The Afternoon. Waves Around 2 Ft Or Less. A Chance Of Rain. |
| Mon Night...S Wind Around 5 Kt. Waves Around 2 Ft Or Less. A Chance Of Rain In The Evening, Then Rain Likely After Midnight. |
| Tue...Sw Wind 5 To 10 Kt, Rising To 10 To 15 Kt In The Afternoon. Waves Around 2 Ft Or Less. Rain Likely, Mainly In The Morning. |
| Tue Night...Sw Wind 10 To 15 Kt. Waves Around 2 Ft Or Less. A Chance Of Rain. |
| Wed...Sw Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. A Chance Of Rain In The Morning. |
| Wed Night...Sw Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. |
| Thu...Sw Wind Around 5 Kt. Waves Around 2 Ft Or Less. |
| Thu Night...Sw Wind Around 5 Kt. Waves Around 2 Ft Or Less. |
| Area Forecast Discussion National Weather Service Seattle WA 139pm PDT Sat Jun 6 2026 Synopsis An upper level trough over Western Washington today will shift eastward tonight. A weak upper ridge will produce a brief drying trend on Sunday before a series of systems produce cool and unsettled conditions for the first half of the coming week. A pattern shift toward dry and considerably warmer conditions is expected late next week as strong high pressure aloft builds into the region. Short Term - Tonight Through Monday Night Daytime heating coupled with an upper trough axis over Western Washington will produce scattered showers, isolated thunderstorms and unseasonably cool temperatures into this evening. The higher terrain of the Cascades and Olympics above 4500 feet will see some light snowfall, but it is not expected to produce any travel impacts across the passes. The trough will shift eastward tonight and a weak shortwave ridge will slide onshore on Sunday allowing the area to briefly dry out though temperatures will remain below normal. The next in a series of troughs will spread additional clouds and showers into the region Sunday night into Monday. It's eastward progression will, however, be hindered as a weak surface low developing off the Oregon coast splits the system apart and takes the focus of the bulk of the precipitation into Oregon. Long Term - Tuesday Through Saturday The cool and unsettled pattern continues into the middle of the coming week as another upper trough digging southward along the British Columbia coast keeps showers and cool temperatures in the forecast. The narrative takes a decided turn from that point forward. Ensembles are virtually unanimous that we'll see a substantive change in the synoptic pattern heading into late next week and the days that follow. A building upper ridge will produce a warming trend that will result in temperatures climbing back to just above normal levels swiftly on Thursday. The climb upward continues as we round out the week and likely beyond. High temperatures by the beginning of next weekend could run 10 to 15 degrees above seasonal averages as anomalously strong upper ridging takes up residence just to our west. Longer term guidance strongly suggests that the upward trend in temperatures will persist beyond the 7 day period. Probabilistic HeatRisk suggests a 90-100% chance of Minor HeatRisk across much of the lowlands by Friday and Saturday and a 40-70% probability of Moderate HeatRisk on Saturday for the interior lowlands of south Puget Sound and the Southwest Interior. Though it's early yet, current probabilistic data has a considerable portion of the CWA (County Warning Area) likely reaching Moderate HeatRisk as we enter the June 14th/15th period with potential daytime temperatures in the mid 80s to mid 90s for interior areas from Seattle southward. Stay tuned. 27 Marine A weak trough over the coastal waters will shift inland tonight as weak high pressure builds just offshore. Another trough and associated frontal system will approach the outer coastal waters Sunday evening then slow and dissipate in response to a weak surface low moving toward the Oregon coast. Onshore flow will increase Tuesday and Wednesday as broad high pressure gradually expands into the coastal and offshore waters. Onshore flow weakens late next week as thermally induced low pressure begins to expand northward across Western Oregon. Coastal seas are expected to remain below 10 feet through the period. 27 Fire Weather Although lightning will be possible today and rainfall amounts may not quite make it up to the 0.25 in threshold separating wet and dry storms, Min RH values exceeding 60 pct should limit any fire weather concerns today. As the generally troughy pattern remains in place over W WA in the first half of the upcoming week, again, some limiting moisture is expected to remain in place. As upper level ridging builds into the area starting Thursday, conditions, including fuels, will need to be monitored as temperatures are expected to climb to above normal values entering into the week 2 time period. NOAA Seattle WA Office: Watches - Warnings - Advisories WA...None. PZ...Small Craft Advisory from 5pm this afternoon to 5am PDT Sunday for Central U.S. Waters Strait Of Juan De Fuca- East Entrance U.S. Waters Strait Of Juan De Fuca. |
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