James Island to Point Grenville WA out 10 NM Marine Forecast
|Today...Nw Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. Nw Swell 5 Ft At 8 Seconds.|
|Tonight...Nw Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 4 Ft At 8 Seconds.|
|Sat...Nw Wind To 10 Kt. Wind Waves 1 To 2 Ft. Nw Swell 3 Ft At 7 Seconds.|
|Sat Night...Nw Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 4 Ft At 9 Seconds.|
|Sun...Light Wind. Wind Waves 1 Ft. W Swell 4 Ft At 11 Seconds.|
|Sun Night...Nw Wind To 10 Kt. Wind Waves 1 Ft. W Swell 5 Ft At 11 Seconds.|
|Mon...Nw Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 4 Ft.|
|Tue...Nw Wind 5 To 15 Kt Becoming Sw To 10 Kt. Wind Waves 1 To 2 Ft. W Swell 4 Ft.|
| Area Forecast Discussion|
National Weather Service Seattle WA
929am PDT Fri May 20 2022
No changes to the overall forecast. Morning clouds over much of the area will lift and scatter out with some sunshine this afternoon. The only exception will be the Olympics and Cascades where afternoon showers are expected. See the aviation and marine sections for updates to those forecasts.
/issued 347am PDT Fri May 20 2022/
SYNOPSIS...Weak upper level trough over the area through Saturday. Trough shifts east Saturday night with weak upper level ridge Sunday. Front dissipating offshore Monday. Another weak ridge moves through Tuesday with the next weather system moving inland to the north Wednesday. Another trough arriving Thursday.
SHORT TERM /TODAY THROUGH SUNDAY/...Satellite imagery shows cloud cover along the coast and over the mountains and Cascade foothills this morning. No precipitation echoes on the doppler radar. Temperatures at 3 am/10z were in the upper 30s to mid 40s.
Weak trough overhead today into Saturday will keep a few showers in the forecast in the afternoon and evening hours both days for the mountains. Light northerly flow aloft could push a few of these showers off the Olympics down to around Shelton late today. For most of the interior lowlands plenty of sunshine both days. The exception to this will be this morning with some cloud cover over the Cascade foothills. Light low level onshore flow today will become flat Saturday. With the trough overhead temperatures today will still be below normal with highs in the upper 50s to mid 60s. A little warmer Saturday with highs mostly in the 60s. Lows Saturday and Sunday morning in the upper 30s to mid 40s.
Trough shifts east Saturday night with a weak ridge of high pressure moving over Western Washington Sunday. Shower activity over the mountains will end quickly Saturday evening. Light flow in the lower levels continuing into Sunday afternoon making for a mostly sunny day. Highs Sunday near or slightly above normal, in the 60s and lower 70s.
Long Term - Monday Through Thursday
Some differences in the extended models Monday with the ECMWF (European Centre for Medium-Range Weather Forecasts) bringing a weak system into Southern British Columbia while the GFS dissipates the front offshore. Because of this GFS ensemble mean for highs Monday are at least 5 degrees warmer than the ECMWF. Both models have low level onshore flow. Because of this will keep highs near normal, in the 60s, for Monday which is closer to the ECMWF forecasts. Weak upper level ridge building over the area Monday night into Tuesday but low level onshore flow will keep highs in the upper 50s to mid 60s. Next system riding over the top of the weak ridge into British Columbia Tuesday night into Wednesday. System close enough to have a slight chance of rain along the coast and over most of the interior Wednesday. More consolidated upper level trough arriving Thursday for the best chance of rain in the next week. Highs in the 60s Wednesday and upper 50s to mid 60s
Winds have eased over the waters with light surface pressure gradients as high pressure builds offshore over the eastern Pacific. Seas holding at 6 to 8 feet and remain somewhat steep, but expect seas to subside today and especially over the weekend. This will maintain rather light winds through the start of next week and while diurnally driven pushes of west winds through the Strait of Juan de Fuca develop, they are expected to remain below advisory
The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated as needed.
NOAA Seattle WA Office: Watches - Warnings - Advisories