Point Grenville to Cape Shoalwater WA out 10 NM Marine Forecast
15 - 25
|Tonight...Ne Wind To 10 Kt Becoming 5 To 15 Kt After Midnight. Wind Waves 1 To 2 Ft. Sw Swell 10 Ft At 10 Seconds Subsiding To 7 Ft At 10 Seconds After Midnight. A Chance Of Showers In The Evening.|
|Wed...E Wind To 10 Kt Becoming Sw In The Afternoon. Wind Waves 1 Ft. Sw Swell 7 Ft At 10 Seconds Subsiding To 5 Ft At 10 Seconds In The Afternoon.|
|Wed Night...Nw Wind To 10 Kt. Wind Waves 1 Ft. S Swell 4 Ft At 9 Seconds Becoming Nw At 8 Seconds After Midnight.|
|Thu...W Wind To 10 Kt. Wind Waves 1 Ft. Nw Swell 5 Ft At 9 Seconds.|
|Thu Night...Sw Wind To 10 Kt Becoming 5 To 15 Kt After Midnight. Wind Waves 1 To 2 Ft. Nw Swell 5 Ft At 9 Seconds.|
|Fri...Sw Wind 15 To 25 Kt Becoming S 20 To 30 Kt In The Afternoon. Wind Waves 2 To 4 Ft Building To 5 To 7 Ft In The Afternoon. W Swell 4 Ft At 8 Seconds.|
|Fri Night...Sw Wind 15 To 25 Kt. Wind Waves 3 To 5 Ft. Sw Swell 5 Ft At 7 Seconds.|
|Sat...W Wind 15 To 20 Kt Easing To 5 To 15 Kt. Wind Waves 1 To 3 Ft. W Swell 7 Ft.|
|Sun...W Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 8 Ft.|
| Area Forecast Discussion|
National Weather Service Seattle WA
950pm PDT Tuesday Mar 28 2023
Mostly quiet this evening as an upper-low continues to track southward tonight. Scattered reflectivity is showing on area radars but with dry air present at the surface given offshore flow, conditions should be mostly dry tonight aside from sprinkles/drizzle for the southern half of the CWA. Overnight lows are to be in the upper 30s to low 40s.
Mostly cloudy and dry conditions will persist through tonight as weather impacts from a strong area of closed low pressure near OR/CA remain to the south. Wednesday will be the warmest day of the week as weak high pressure sets in ahead of a shift back to cooler and wetter conditions the latter half of the week and through the weekend. A seasonally strong front will cross the area late Friday into Saturday, with showers continuing through the weekend. Additional rain chances and cool weather will then persist through early next week.
Short Term - Tonight Through Friday
The upper level low and its associated surface reflection will weaken some and slide south towards the N CA Coast tonight, allowing a weak ridge of upper level high pressure to approach the area. This should help begin to clear skies from the north tonight, with any moisture over the southern half of the area pushing further south towards the WA/OR border. Expect skies to then clear more from north to south Wednesday morning as high pressure arrives, with lingering moisture mostly confined to central and eastern Lewis County, particularly the southern Cascades. Weak subsidence aloft and clear skies should allow Wednesday to become the warmest day of the week with high temps reaching the low 60s. Some cloud cover is expected to advect in as a subtle shortwave approaches the southern BC Coast.
Wednesday night will be dry with ridging slowly becoming replaced by weak troughing in the mid/upper levels. More cloud cover and the development of isolated showers (mostly along the coast and higher terrain) will lead to an overall cooler day with highs in the mid/upper 50s. Current forecast could still be a bit aggressive with rain chances given the shortwave trough's largely continental trajectory and overall lack of impressive dynamics and moisture.
Conditions will then noticeable change on Friday as the next organized, seasonally strong frontal system approaches the area. Pre-frontal showers should increase in coverage Thursday night into Friday with rain arriving along the Coast sometime Friday afternoon or evening. Precip will then spread inland overnight and through Saturday morning, resulting in measurable lowland rain and heavy mountain snow. Winter headlines appear likely to be issued in future forecast updates for this system, with travel impacts likely across the Passes.
Long Term - Saturday Through Tuesday
The local area will be in an unstable post-frontal environment in the wake of Friday night's frontal system to begin the long term. Upper level trough influence will increase as the day progresses on Saturday, resulting in widespread shower activity across the area. This activity is likely to be convective, resulting in the potential for a few lightning strikes and small hail. This general pattern will hold strong through Sunday, likely enhanced at times by subtle vort maxes within the broader trough, resulting in widespread showers through the entire weekend. Colder air aloft and the cooler post-frontal airmass will result in weekend high temperatures in the upper 40s to around 50, with lows back in the 30s.
Ensemble guidance is in good agreement with upper level troughing continuing to be the primary weather influence through early next week. There is some discrepancy in the strength of the trough, but despite this, it is a fair bet that the weather will remain cool and wet through at least Tuesday.
Moderate offshore flow will gradually weaken overnight as a surface low west of the OR/CA border continues to shift southward and fill over the next 24 hours. The flow will turn onshore Wednesday afternoon as surface ridging builds into the coastal and offshore waters. This might be enough to produce small craft advisory westerlies in the central/eastern Strait of Juan de Fuca Wednesday evening. A weak surface trough over the interior waters on Thursday will keep winds across the waters under advisory levels. The next in the series of fronts emerging from the Gulf of Alaska will reach the area by later Friday and is likely to generate additional headlines for area waters. The active pattern will persist into the coming weekend.
S/SW swell over the coastal waters will approach 10 feet over southern areas this evening before subsiding later tonight and Wednesday. Coastal seas are then expected to remain below 10 feet before building again this weekend. 27
No river flooding is expected through the next seven days.
NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...None. PZ...Small Craft Advisory until 9pm PDT this evening for
Central U.S. Waters Strait Of Juan De Fuca-
Coastal Waters From Cape Flattery To James Island Out 10 Nm-
West Entrance USA Waters Strait Of Juan De Fuca.
Small Craft Advisory until 5am PDT Wednesday for
Northern Inland Waters Including The San Juan Islands.
Small Craft Advisory until midnight PDT tonight 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.