James Island to Point Grenville WA out 10 NM Marine Forecast
|Tonight...Nw Wind 5 To 15 Kt Becoming 10 To 20 Kt After Midnight. Wind Waves 1 To 3 Ft. W Swell 4 Ft At 10 Seconds.|
|Wed...W Wind 5 To 15 Kt. Wind Waves 1 To 3 Ft. W Swell 4 Ft At 10 Seconds.|
|Wed Night...Nw Wind 5 To 15 Kt Becoming 10 To 20 Kt After Midnight. Wind Waves 1 To 3 Ft. W Swell 4 Ft At 10 Seconds.|
|Thu...Nw Wind 15 To 25 Kt Easing To 10 To 20 Kt In The Afternoon. Wind Waves 1 To 3 Ft. W Swell 4 Ft At 10 Seconds.|
|Thu Night...Nw Wind 15 To 25 Kt. Wind Waves 3 To 5 Ft. W Swell 4 Ft At 10 Seconds.|
|Fri...Nw Wind 10 To 20 Kt Rising To 15 To 25 Kt In The Afternoon. Wind Waves 1 To 3 Ft. W Swell 7 Ft At 11 Seconds.|
|Fri Night...Nw Wind 15 To 25 Kt. Wind Waves 2 To 4 Ft. W Swell 6 Ft At 11 Seconds.|
|Sat...Nw Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 6 Ft.|
|Sun...Nw Wind 5 To 15 Kt Becoming 10 To 20 Kt. Wind Waves 1 To 3 Ft. W Swell 7 Ft.|
| 245 PM PDT Tue Jun 22 2021 |
Northern and Central Washington Coastal and Inland Waters - PZZ100
High pressure over the northeastern Pacific will remain in place with lower pressure inland resulting in onshore flow. Thermally induced low pressure will be over the region this weekend with light pressure gradients.
| Area Forecast Discussion|
National Weather Service Seattle WA
210pm PDT Tuesday Jun 22 2021
Onshore flow and marine air will moderate temperatures across Western Washington through Thursday. An extended period of hot weather is on tap for the end of the week and into early next week. Record highs are likely over the weekend.
Short Term - Tonight Through Thursday
Clear skies over much of W WA this afternoon although still have a little bit of coastal stratus lingering with a wedge of clouds still present running from Hoquiam to Shelton. Current satellite trends show this area thinning, so partly cloudy to clear skies may be possible for these locations this evening...just in time for the next round of stratus to start moving in.
Current temps over W WA show a significant difference in temps today compared to yesterday. Depending on the location, temps at this hour are anywhere from 5 to 20 degrees cooler than this time yesterday. Sea-Tac is showing about 11 degrees cooler than 24 hours ago. The big winner here is Shelton, being 20 degrees cooler than yesterday, thanks to the aforementioned still lingering stratus. Still may see some additional heating today which would again put temps above normal for this time of year.
This onshore flow will persist into Wednesday resulting in more widespread morning marine stratus and the coolest temperatures of the week, but in context that still puts highs in mid to upper 70s for interior lowland locations. Given that normal highs this time of year are generally in the upper 60s to lower 70s, even this coolest day is still anywhere from 5-10 degrees above normal depending on location.
The combination of a building upper level ridge and weakening onshore flow will allow temps to rise again for Thursday, with highs expected to be similar to what is expected for today /that being upper 70s to around 80/. Morning marine stratus will still be present, but likely hanging closer to the coast and burning off earlier. 18
Long Term - Friday Through Monday
The aforementioned ridge will not be in an hurry to go anywhere...and this is the portion of the discussion where it is important to remind the reader not to shoot the messenger. The lingering ridge is expected to drive temperatures upward significantly as it slowly plods eastward throughout the entire long term period. High temps for coastal locations look to climb into the upper 70s Friday and the mid 80s Saturday before cooling back down to upper 70s to low 80s Sunday and Monday. For the interior lowlands, Friday should see highs in the upper 80s to lower 90s, Saturday and Sunday in the upper 90s to low triple digits before easing into the 90s for Monday. Ensemble forecasts remain in good agreement regarding this heatwave with quite a number of members dragging the ensemble mean upward. Also disconcerting during this time frame will be overnight lows as inland locations will see low temps only falling to the mid to upper 60s. The coast looks to be spared this as overnight lows during this period will sit generally around 60. With all of that being said, have collaborated with surrounding offices and agreed that given this high degree of confidence, an Excessive Heat Watch would be prudent and will go out with the afternoon forecast package, running from Friday afternoon all the way through Monday. This will also allow for room for future shifts to adjust the watch area as needs be as well as determine if and how this should be upgraded, whether to a heat advisory or excessive heat warning. 18
Marine air will continue to push into Western Washington through Wednesday and the westerly push in the Strait should be pretty strong through this evening with a good 20-30kt. Onshore flow will ease Thursday and thermally induced surface low pressure will be over the area for the end of the week and through the weekend as a strong upper ridge moves over the area--so gradients will be light with hot weather especially over the weekend. 19
The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated as needed until then.
.SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory until 11am PDT this morning 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.
Small Craft Advisory until 5am PDT Wednesday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 5pm this afternoon to 5am PDT Wednesday for Admiralty Inlet-Northern Inland Waters Including The San Juan Islands.