Marine Weather and Tide Forecast for Grapeview, WA

SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/
Temperatures this afternoon running 10 to 15 degrees cooler than yesterday -aided by the stronger onshore flow and mid level clouds that have settled over the interior. This will translate into near normal overnight temperatures with a few lingering clouds especially during the evening.

The cooldown will be shortlived as upper level heights build quickly behind todays weak system as it moves into the Intermountain area overnight. Low level onshore flow also weakens and becomes northeasterly as a thermally induced surface trough works northward along the Oregon coast. Hires models - including the ensembles consistently show the surface trough remaining over the Oregon and SW Washington coast, if not slightly inland. This will help keep the low level more northerly than easterly for much of Western Washington.
Nonetheless, highs in the interior will reach the 80s to low 90s on Tuesday, with widespread 90s on Wednesday - leading to widespread moderate HeatRisk levels over much of the interior. The immediate coast will remain in the 60s with a sharp gradient to 70s and even 80s a few miles inland. Overnight lows will also remain relatively warm especially Tuesday night into Wednesday morning, with many areas showing 50 to 70% probabilities of lows remaining in the low 60s. These odds are higher for the metro area from Tacoma to Seattle where the odds are over 90%. In addition, the N/NE winds aloft which may bring Canadian wildfire smoke into western WA Tuesday remaining generally aloft except for higher elevations in the north Cascades.
The flow will turn westerly on Wednesday for less smoke intrusion over the westside.

LONG TERM /THURSDAY THROUGH MONDAY/
The pattern begins to transition Thursday with weaker low level onshore flow bringing cooler conditions to the coast Thursday- Friday. Warmer conditions will likely linger in the interior, especially the metro area where high temperatures will remain warm and in the 80s. More developed onshore flow this weekend looks to finally brings temps back to normal - but remaining dry.

AVIATION
Northwest to northerly flow aloft as an upper level ridge remains offshore. VFR conditions at most terminals this morning as stratus wasn't as expansive than initially forecast. But, stratus remains along the coast and parts of the interior and should linger until 18z (with the exception of KHQM). Northerly surface winds this morning turning somewhat southwesterly this afternoon.
Winds will turn back northerly tonight and lighten.

KSEA...VFR this morning and into the day. N winds this morning around 3 to 6 kt. Winds will gradually lessen early this afternoon as winds turn southwesterly for a couple of hours. Northerly winds will return around 00z between 5 to 10 kt.

McMillian

MARINE
High pressure remains offshore giving way to light onshore flow across the area waters. Diurnally driven westerly pushes down the strait will continue over the next several days with various strengths. A Small Craft Advisory will continue for the coastal waters for elevated winds and steep seas. Thermal troughing looks to build along the coast through midweek, with periodic increases of northerly winds through the area waters.

Coastal seas 8 to 10 feet and will generally remain through the first half of the week.

McMillian

FIRE WEATHER
As high pressure returns to the area beginning Tuesday, expect to see afternoon RH values dip down critical thresholds Tuesday afternoon with a thermal trough building north over the Cascades. While some uncertainty remains with respect to how far north and west this builds, expect to see at least some light east component to the surface winds near the Cascade gaps in zone 659 and portions of 657 and 658. Confidence is lower in seeing more widespread easterly wind, but this may serve to further reduce RHs. Additionally, depending on the placement of the thermal trough, expect to see a deeper mixed layer and increased instability over the Cascades with mixing heights potentially rising into Wednesday.
While confidence in the specific timing of elevated fire weather concerns is still lower, the mid week period will have the worst of the fire weather conditions for existing incidents and for the potential for any new ones were to begin. Looking ahead to the end of the week, expect conditions to moerate but remain warmer and drier than normal. However, forecast guidance continues to exhibit a large range of potential scenarios that leave confidence lower than normal. Cullen/JBB

SEW WATCHES/WARNINGS/ADVISORIES
WA...Fire Weather Watch from Tuesday morning through Wednesday evening for Black Hills and Southwest Interior Lowlands- West Slopes of the Central Cascades Generally above 1500 Feet-West Slopes of the North Cascades Generally above 1500 Feet.

Heat Advisory from noon Tuesday to 10 PM PDT Wednesday for City of Seattle-Downtown Everett / Marysville Area-Eastern Kitsap County-Eastside-Foothills and Valleys of Central King County-Foothills and Valleys of Pierce and Southern King Counties-Foothills and Valleys of Snohomish and Northern King Counties-Foothills and Valleys of Thurston and Lewis Counties-Foothills and Valleys of the North Cascades-Lowlands of Lewis and Southern Thurston Counties- Lowlands of Pierce and Southern King Counties-Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Middle Chehalis River Valley- Northern Hood Canal-Olympia and Southern Puget Sound- Shoreline / Lynnwood / South Everett Area-Southern Hood Canal.

PZ...Small Craft Advisory until 5 AM PDT Tuesday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm- Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.